How to improve the quality of AMR audio recordings in Windows?

Question: How to improve the quality of AMR audio recordings in Windows?
Answer: What are you recording? I guess you are talking about the material you were referring to in your previous questions. If so, then you can't really improve the quality.
To be more general: You can't improve the objective quality of a recording after it is done.
You could improve:

The microphone used for recording
The signal chain altogether (cables, shielding)
The analogue to digital converters
The file format (i.e. using uncompressed WAV instead of AMR or MP3 files)

If you have a small voice recorder, as I would guess from your questions, you obviously can't change anything of this except for using a directional external microphone which would help make voices stand out from ambient noise.

A super-cardioid microphone is similar to a hyper-cardioid, except there is more front pickup and less rear pickup. These three patterns are commonly used as vocal or speech microphones, since they are good at rejecting sounds from other directions.

In my previous answers however I mentioned equalizing as a proper technique to filter noise out and improve voice recognition. This might help you subjectively improve the quality.
Comment: This file is a different one and it has some recordings which is recorded using AMR format I tried increasing the kbps(knowing it might not help) and it didnt. And I need to understand the audio recordings in it so manually itself i couldnt understand it so need to find ways to give more clarity ,etc to it
Comment: For future recordings I can use all of your great suggestions, but i need to process this file somehow and hear it and understand the recordings... some how the mic sensitivity or something got messed up while recording so it became less quality than other files...


Prevent metasploit meterpreter process migration

Question: Is there any way to prevent meterpreter process migration.?
Comment: Are you talking about the endpoint that has been compromised?
Comment: Yes....Like the attacker has already got the shell or else he somehow get access to open(unlocked) unattended machine...
Answer: Based on this question, process migration requires the SeDebugPrivilege to create a thread attached to a remote process, so denying it should block the migration process. Sadly, there is no clear definition on how to do it, but seems like this privilege is part of the user / group privileges so using a non-admin user without this privilege should block process migration.
Also any advanced AV-System should be able to detect and block process migration, but I only tested it on Kaspersky which did block mirgration.
Comment: In my case Kaspersky could not block.!! Though have not checked with any other yet.
Comment: I've tuned my Kaspersky settings to do extensive behavior analytics, maybe that's required to block migration.


Full Screen background slideshow that allows image placements

Question: Ok i have tried 2 different full screen/full width slideshow .
http://nicinabox.github.com/superslides/
http://buildinternet.com/project/supersized/slideshow/3.2/demo.html
but those don't work as i need them to.
I'm looking for a full width content slider, that adjust with screen size and allows me to place images above it.
Something like -----------> Taylorswift.com
See how there is a background slideshow and she can place images on top on the background with each slide.
When i tried doing that with those two sliders it didn't work. With the first slider the image just stretched. and the second slider isn't an html slider.
I even tried adjusting the css myself.
Anyone know where i can find a slider like the one on ----> Taylorswift.com
Answer: I think what you are looking at is the there in Royal Slider. http://dimsemenov.com/plugins/royal-slider/
you can check various implementation here http://dimsemenov.com/plugins/royal-slider/templates/
I use this slider and it's kinda cool. I am no way affiliated to them just make sure you check other alternatives before buying


Having a meeting with my senior manager and my direct manager over work future

Question: I just started in this company full time as a software engineer 3 months ago. I was an intern for 2 years before I came in full time. The job is in the defense industry so I was required to get a clearance in order to do my job. So coming into the job as a level 1, I thought about asking for a level 2 position because my active clearance already gave me access to do real work versus being paid for a year to do nothing on our off base location. I also worked and have taken on projects that full time engineers would have taken. When I inquired I was told they don't promote that way and I would have to wait. However, a friend of mine just got hired on with no prior military clearance at a level 2. This means he will get increased pay and benefits, but I feel a bit cheated considering I will be paid less while actually doing work.  I wish I had known sooner so I could better prepare, but now I am not sure how to approach my meeting tomorrow. Should I wait for the end of the year to discuss a possible promotion? Is this the proper meeting to discuss a promotion? Any input would be great.
Comment: Possible duplicate of [How should I properly approach my boss if I'm feeling underpaid?](https://workplace.stackexchange.com/questions/1025/how-should-i-properly-approach-my-boss-if-im-feeling-underpaid)
Answer: You came in at entry level because you are entry level. Having a clearance doesn't change that. Your friend may have lied to you as to what he came in at or he may have some experience that makes him seem more than entry level or they may feel he has better technical skills or maybe he just wouldn't accept the offer until they upped it (or he had another offer on the table at a similar level). Who knows. It is irrelevant.
There is almost always someone who is higher than you who you may not feel is as good as you are. In every large company, in pretty much every medium company and even in many small companies. That is because some people are better negotiators, some people have skills you don't know about, some people have better political skills and many people overestimate their own skill level. You need to simply accept that and not let it bother you. Instead concentrate on what you can do to get promotions and better or more interesting projects.
What you need to do before asking for a promotion is have some accomplishments to prove your value to the business. What you can do right now is ask your boss what he feels you need to do in order to be promoted to the next level. Then go out and do those things and do them well. Then you ask for the promotion.
Answer: Don't ask for a promotion yet. It's okay to feel frustrated and underpaid, if are qualified for a higher level position. The problem is that you don't seem to have really planned this out, especially with your boss. The two of you should work together to outline what they want you to accomplish to be successful at your job and how you can grow to learn and take on greater responsibility. The result should include specific action items that will help you work toward promotion (not guaranteed promotion, but progress toward it). Using this approach will allow you to ask your boss whether they think you are qualified for the promotion now or what it would take to get there.


What causes muscle stiffness contraction and tension during stress

Question: What causes muscle contraction in times of stress? People say it's caused because of fight or flight response is activated, but this not exact. I am looking to find the direct cause, i.e is it a direct effect of adrenaline or maybe a direct effect of cortisol? Maybe is because glucose levels rise and it's the way of our body to use that extra energy? I don't really know and searching doesn't help.
Answer: Presumably you to mean to ask what pathway mediates muscle tension. muscle tension is controlled by the reticular formation (in the brain stem), so it doesn't require anything special to happen in the bloodstream. The reticular formation is connected to many other areas of the brain.
To save this question from triviality and relate it to your prior one (which was about anxiety), muscle tension is the most common (if not the defining) feature of GAD, yet muscle tension cannot be understood in terms of the autonomous nervous system (ANS) response to stress (according to a 2009 review of Pluess et al.) That's basically a coy of saying we don't know what exactly causes muscle tension in GAD. Furthermore, some studies of GAD reported that the typical ANS responses to stress are not present in many GAD patients (according to the aforementioned review citing in Hoehn-Saric et al.). The latter issue is more controversial because a later (and more cited) study of Thayer et al. did find some correlates with ANS in terms of cardiac activity, but this still doesn't quite provide a complete explanation. Another 2009 GAD review discussed 5 different conceptual models of GAD, yet none of these theories does much to explain muscle tension in GAD.
Comment: Yeah I guess more research needs to be done to the subject. After some googling I came to my own theory where I think the tension may occur because adrenaline makes blood vessels constrict, which results in less oxygen to travel to the muscles and that may cause them to contract .


When Marty travels back to the future, why are not there two of him in 1985? Or they indeed are?

Question: When Marty travels back to 1985 from 1955 at the end of the 1st BTTF movie (and meets his all new present), aren't there two Marties in that moment (the one that has just arrived and the one that was born thanks to his collaboration in making their parents to fall in love one with each other in 1955)? If not, why?
Comment: Um, maybe you didn't watch the end of the movie, where Marty watches his other self go back in time, just before he gets to Doc?
Answer: OK, now I realize of it. It has to do with this other question: What happens to the second Marty at the end of Back to the Future?
There are not two Marties in 1985 except during the moment in the shopping mall, when the newly arrived Marty sees the other Marty travelling back to the past, which closes the circle.


data format changed when importing data from Mysql to Hbase

Question: I am using sqoop to import data from Mysql into Hbase.
It works fine but there is one issue.
As i read from Sqoop documentation , sqoop converts mysql data into String and then store it in Hbase.
However this would be problem for me as i will have to export data back from Hbase to Mysql and at that time , how will sqoop deduce data type information for the Hbase data ?
Someone please help for solution to this problem.
Comment: Can someone please reply.
Answer: What you can do is - during export, just export it to a temporary table in MySql side. At that point the datatype will be different. Then write a query to insert them to the original MySql table from the temp table and during this time filter out unexpected data or convert datatype.
I faced pretty similar issue with timestamp datatype as in Hive I was storing it as bigint. During export I first inserted them as it is to make Sqoop export works. If its successful then I run a query that actually load those data from temp table to original table while converting the data at the same time. Hope it helps.


Are Arista SFP Transceivers Compatible with Cisco Switches?

Question: Are the Arista SFP transceivers compatible with Cisco switches?  For example, if I go to the CDW site they show multiple transceivers that vary in price.  How can I know that they will work in the Cisco 2960 switch I have?
Answer: If the media is supported the SFP(+) will most likely work, note that Arista SFP+ SR-lite is only supported by Arista.
On the Cisco device you must enter this command to enable use of 3rd party optics:
service unsupported-transceiver
Answer:
It depends of the brand and model of the SFP/Gbic
It depends of the model of the switch.

Some routers and switches will refuse to use a Non-cisco SFP (eeprom check), while some others will need the following commands to make it work (and some others just work):
switch(config)# service unsupported-transceiver
switch(config)# no errdisable detect cause gbic-invalid

On IOS-XR:
RP/0/RSP0/CPU0:ios#sh run int te0/0/0/0
interface TenGigE0/0/0/0
 transceiver permit pid all

Some Finisar's are known to work, while some Zycko's works even without "service unsupported-transceiver".
You can also browse through Cisco-nsp mailing-list archive to find more informations about (compatible or not) vendors.
Answer: I don't have any direct experience with arista SFP and cisco switches but the SFP interface is standardized such that it is supposed to work.
For instance, I use an Avici SFP module in a Linksys switch.  I have used Juniper SFP modules in enterasys switches and Extreme branded modules in Juniper firewalls.
I have also seen weird things with copper sfp 1g modules (generic modules from CDW and Juniper branded) not working in an enterasys sfp+ interface, so it isn't 100% certain, but for something like a cisco 2960, cisco would have to have gone out of their way to break SFP compatibility, and they're big enough that I suspect they'd avoid doing that to avoid scrutiny from regulators.
Now, if it works or doesn't work, it won't be supported.  It won't void your warranty or anything, but if you have weird problems related to that link, I wouldn't advertise that you're using a non-cisco branded module.
Comment: Good answer, I typically keep one legitimate supported SFP on hand I can swap in, in case support has a gripe about the physical link.
Answer: I keep running into this more and more. Swapping branded SFP's around will always cause problems, it depends if the device is checking EEPROM and what the EEPROM is holding in memory.
Rather than swap out 2 different brands of SFP I would just go for a low cost compatible. Finisar SFP's are usually a generic code to work in 'most' devices. You need to get SFP's specific to the device to be sure.
Please see this document regarding the compatibility of SFP's and also a FAQ I put together in an attempt to straighten out some of the confusion on this topic.
http://www.netwerking.co.uk/sfp
Answer: Yeah,Compatible SFP with Cisco switch is available,just write the EEPROM accourding to cisco switch's model.


Magento 1.x custom block with dynamic content

Question: Is it possible to add a block to Magento page which has dynamic content.
Let's say I want to create a block in which a product is displayed. And after a certain period time 15 seconds for example the product changes and another one is displayed.
Answer: Yes, you have to create your phtml file then you include it in the page that you want, with xml or directly in a page code, then you customize it with js for exemple.
To include it:
1) You create the phtml file app/design/frontend/{package}/{theme}/template/catalog/product/homeproducts.phtml then you add your custom code
2) to include it via cms page:
{{block type="core/template" name="home.product" template="catalog/product/homeproducts.phtml"}}

via xml:
app/design/frontend/{package}/{theme}/layout/local.xml
<your_layout_handle> //where you want to display your block
        <reference name="root">
            <block type="core/template" name="home.product" template="catalog/product/homeproducts.phtml"/>
        </reference>
</your_layout_handle>

3) Go to your phtml that you want to display this new block then add this:
<?php echo $this->getBlockHtml('home.product'); ?>


How do I restrict the users from installing applications from being installed on the linux machine?

Question: How do I restrict the users from installing applications from being installed on the ubuntu linux machine? I have root privileges and there are three users in the ubuntu linux machine. I would like to restrict the users from installing any "web browsers" or specific web browsers from being installed. (These users have sudo access)
Comment: restricted sudo access I hope you mean, since with full sudo access, they can undo anything you can do as root.
Answer: If the users have sudo privileges, it is almost impossible to restrict them from doing something unless you specify a whitelist of specific commands they are allowed to use.
If asking the users not to do something is not good enough, then look at this SuperUser SE answer for other possible solutions.
Answer: Since Google Chrome can be installed without sudo, there is no reasonable way to prevent users from running it no matter how hard you try. This may apply to other browsers as well.


Black screen Kali Linux 2016.2 on VirtualBox

Question: Does anyone know the solution to the dreaded black screen on Kali Linux when booting from VirtualBox? I imported the ova appliance straight from Kali's website (Kali-Linux-2016.2-vbox-i686.ova) and, set the video memory to 128MB, switched the USB 2.0 to USB 1.0 as instructed (to get it to boot at all).
I've tried the "root"/"toor" combo as suggested by other posts, but nothing seems to work. It looks like it's running, however. Never had this problem with other versions of Linux to date.
Any ideas?
Comment: I have the black screen problem with the latest Kali VirtualBox Image 2019.2 with Virtualbox 5. I updated to Virtualbox 6, and the problem is solved. Kali VirtualBox Image is usually made with the latest virtualbox, so it's a good idea to keep your Virtualbox up to date, if you encounter any problems.
Comment: Did you properly install the Grub boot loader?You have to click `yes` in the option which appears in the end of installing the kali VM - "Install the Grub boot loader to the Master boot record"
Comment: I think your problem is in video memory. Go to Settings->Display and give it at least 32 MB
Answer: I just had this issue.  It turned out, after trying a bunch of other stuff, that it was caused by the OS being set to Ubuntu 32 bit instead of 64 bit.
I turned back on the stuff I had turned off, like PEA/NX, 3d acceleration, etc. from the default.  Seems to work fine now that it has the correct OS.
Worked for me, hope it helps someone.  BTW - host system is Windows 10 Pro 64 bit.
Answer: I had a black screen running Kali in Virtualbox just after installing it and installing all the updates and was able to fix it by  going into system settings in Virtualbox and just unchecking the Enable 3d acceleration box in the Display settings.
Answer: Kali Linux on Virtual Box - I think this is the same question. I just answered this guy too. I had the same problem. I had a black screen because kali was running, but I couldn't see it. So, click view at the top and select switch to scaled view. This should adjust the display so that kali recognizes it and shows you what you should be seeing.
Comment: That worked but screen not updating, just got stuck
Answer: I've been struggling with the black screen issue for a LONG time.
Here's how I was able to fix it the other day.

Launch virtualbox, go to help > about virtualbox

Take a look at your current version. If you're running a 5x version, then you have found your issue.

Remove virtualbox from your machine. If you're on linux, use the following commands(your vms shouldn't be deleted when doing this)
sudo apt-get remove virtualbox; sudo apt-get purge virtualbox*;

Once you've uninstalled virtualbox, go and download the latest version from the website : https://www.virtualbox.org/wiki/Linux_Downloads  Make sure that you get the one for your current version of linux. Find your current version with this command  uname -a

After downloading the virtualbox deb package, install it with the following command(replace the file path with that of your specific deb package) :
dpkg -i ~/Downloads/virtualbox-.1_6.1.18-142142~Ubuntu~bionic_amd64.deb

Once done, you should be able to launch virtualbox and run kali without issues.
I figured out that this was the issue for me after learning that kali is developed and tested using the most recent versions of virtualbox and vmware.
Hope this resolves the issue for someone else too!
Comment: this one works for me. My version was 5 and now it works
Answer: The problem is that the laptop VirtualBox is installed does not have hardware virtualization as an option (a low end dual core intel B960 CPU) which explains a lot.  The solution is to tell Kali to not look for Xen at boot.
These instructions will solve this little problem.
Press "e" at the boot menu, scroll to the line that starts with "linux" and remove "quiet" and add "noreplace-paravirt" to the line, hit ctrl-x and let it finish booting (may take a couple of minutes), then login.
Open a terminal and edit the /etc/default/grub w/editor of your choice and change GRUB_CMDLINE_LINUX_DEFAULT="quiet" to "GRUB_CMDLINE_LINUX_DEFAULT="noreplace-paravirt"
Run "update-grub" and reboot.
Comment: Note: the low end CPUs are so slow, it's better to just either boot from a USB or create a dualboot system, rather than using a VM.
Comment: In my Kali Linux version (2017.1) I scrolled to the line in the boot screen (for me it was Graphical Install), then hit the Tab key to edit the line, replacing "quiet" with "noreplace-paravirt". Then the install worked.
Answer: I've installed Kali 2019 using having enabled EFI mode for the VM. Reinstalling without that option enabled did the trick.
Answer: Enable PEA/NX in settings -> system -> Processor
Comment: C'mon for real... Provide a whole lot more detail than just this like explaining what these options do perhaps or otherwise....You might need to be converted to a comment, feel free to flag a mod and ask for this to be done until you earn enough rep to write comments... this is an easy and simple task too by the way.


MP1584 step down short circuit efficiency

Question: If I use MP1584 step down IC and short circuit appears how can I calculate the efficiency or the total power dissipation for the IC?
Answer: You are asking two questions: efficiency of regulator into a short circuit and power loss in regulator in short-circuit condition.
The first is easy:
Efficiency is give by formula \$ \eta = \frac {P_{OUT}}{P_{IN}} \$ and power can be calculated from \$ P = VI \$.
For the short-circuit case \$ V_{OUT} = 0 \$ so we have
$$ \eta =  \frac {P_{OUT}}{P_{IN}} = \frac {V_{OUT}I_{OUT}}{V_{IN}I_{IN}} = \frac {0 I_{OUT}}{V_{IN}I_{IN}} = 0 $$
The chip power dissipation is not so easy to calculate as it may depend on inductor saturation, etc., but we don't have to.

Figure 1. Maximum continuous power dissipation is given in the datasheet.
In any case the regulator will shut down at 150°C and turn back on at 135°C.
Comment: Thanks. If the input voltage 24V and short circuit apperars on the output how much will the power dissipation if the inductor is 10uH and saturation current is 6A, diode is schottky diode 40V 5A (SK54), Vf: 0.5V (at 5A)
Comment: You measure it, or you simulate using very detailed models.


Can a property's value be set according to another property of the same element?

Question: I want to set the padding-bottom property of an element like this:
padding-bottom: 100% - height;
where height is the height of the object which I'm going to set it's padding-bottom.
I'm not changing the height and it will be automatically set according to the contents of my element.
For example given the properties of element elemID:
#elemID {
    margin: 10px;
    border: 2px solid #111;
}

How can I set it's padding-bottom according to it's height and more generally how can I access "the value" of other properties of an element in CSS.
I saw this question but it's not what I want as in my case the value of height can't be predicted and I don't want to use variables but properties. I know that this problem can be solved in JS but I want to know if there is a way to solve it in CSS?
Comment: What do you really want to do?  In other words, why do you want to set the padding of one element to the height of another?   Perhaps it can be done a different way.
Answer: The answer, sadly, is no. The cascading style sheet language offers no way to reference properties on elements. Variables are the best native CSS work-around, but you already said that won't do. JavaScript will be the best and easiest way to get a "dynamic" reference to height.
Here's a reference to a similar question asked where the answer kind of addresses yours. The solution was to use SASS and have a list of potential heights that could fit, however that doesn't really answer your question. I thought I'd leave it for reference, though:
Creating or referencing variables dynamically in Sass
Comment: Thank you @lua_python_java . It seems like there isn't any way in CSS and the best option is to run JS onload to change the style that way.


Need a list of all the people in Buddhas life

Question: I need a list of all the people mentioned in the Pali canon who were in the story of the historic Gautama the Buddha. For e.g. Angulimal, Ananda etc. I did a google search for the same but did not find the answer. Also, if you can provide sutta reference for their mention that will be great.
Answer: Please try AccessToInsight (ATI)'s Index of Proper Names.
On this page, please search for the following phrases:

"Buddha's"
"of the Buddha"

You will find phrases like "Buddha's father", "Buddha's cousin", "son of the Buddha", "Buddha's first meditation teacher", "half-brother of the Buddha", "Buddha's chief personal attendant" etc.
The ATI page will provide sutta references, if available.
For a description, please next refer to Palikanon's Buddhist Dictionary of Pali Proper Names.
For example, on the ATI page, you can find:

Suddhodana (Buddha's father): Sn 3.11

Then on Palikanon:

Suddhodana

A Sākiyan Rājā of Kapilavatthu and father of Gotama Buddha.
He was the son of Sihahanu and Kaccānā. His brothers were Dhotodana,
Sakkodana, Sukkodana and Amitodana, and his sisters were Amitā and
Pamitā.
Māyā was his chief consort, and, after her death her sister Pajāpatī
was raised to her position (Mhv.ii.15f.; Dpv.iii.45; J.i.15, etc.).

and it continues with further description on the Buddha's father, his life and background.


How to get enough Sepolia eth to test staking?

Question: The Sepolia faucets prescribed here dispense a limited amount of eth each day. However, in order to test solo staking, one needs a non-trivial amount of eth. What is the most efficient way to procure enough eth for a solo staking setup so that multiple validation keys can be tested?
Answer: Sepolia is a permissionned testnet which mean you cannot test solo staking there.
It's still possible to test solo staking on Goerli but getting the required Goerli ETH might be problematic. At EthStaker, we have a <code>#cheap-goerli-validator</code> channel and process that can guide anyone from having zero Goerli ETH to performing the required Goerli validator deposits in a few minutes with a Discord account. Simply join the EthStaker Discord.
This process will not get you any meaningful amount of Goerli ETH no matter what but you'll still end up with a full validator on Goerli. We also have minimal checks and delays in order to prevent abuses.
Comment: @tezette The plan is to move to a new network called Holešky (Holešovice Testnet) which is going to be permissionlesss like Goerli.
Comment: What happens when Goerli is deprecated later this year? Where can one test solo staking then?
Comment: More testnets are being implemented to help with new stakers testing their setup before going on Mainnet. Ephemery is another testnet that can be used for that but it currently requires more efforts to use. We are working to help in making this easier for everyone.


Firebase Vision confusing characters

Question: I'm using Firebase Vision, from MLKit, together with CameraX for text recognition in Android. The problem is that the results are not very consistent. Depending on the font, these recognitions may vary. For example, sometimes it's confusing the character 'b' with the digit '6'. This is not a problem if you only need digits in your result. But sometimes it's confusing digit '7' with digit '1', which is quite annoying for a digit detector.
Is there any way to improve these results? Larger bitmaps could help? Any ideas on what can I do?
Answer: I suspect the image resolution is the issue here. It's that or you are hitting the limit of what the detection algorithm is capable of.
Could you try CameraX's MlKitAnalyzer API? It automatically configures MLKit to give you the best result.

Firebase Vision confusing characters


Where can I find a good guide for The Guild II?

Question: Where can I find a good guide for The Guild II?  Preferably one that would address all four professions, and even the expansion (Pirates of European Seas).
Answer: This blog contains a guide on The Guild II. I skimmed over it, and it covers the four classes, basic mechanics of the game, AI, and a few other things.


Setting up Openfire in MAC OS X

Question: I have installed openfire 3.9.3 on MAC OS X Yosemite Version 10.10.2.
having trouble in setting up openfire. After installing openfire I am getting the error like could not start openfire.
Answer: To get latest version of java (jdk) and install it and install latest version of openfire .its working fine for me
Answer: To get started on the installation and setup, you need to grab the most current version of Openfire from the Ignite Realtime web site.
Click here! and follow step by step

Setting up Openfire in MAC OS X


Create a multicast router

Question: How can i make my laptop to act as a multicast router.
I need to stream video content to other computers with in same network. How can i make my laptop to work as a multicast router.
Answer: There are some tools like that iou,iou2net.pl
Answer: It's simple - write a simple app to recieve multicast on one network card and simply re-send it on another one. One packet in - one packet out. And this way you can make userspace multicast router. Very easy. Just dont forget to register IGMP on these sockets.
This way you can also send it to multiple networks at once, etc etc.
Answer: Say you install Cisco IOU on a VM (ubuntu) or directly if you already use ubuntu.
Every instance you run (level 3 bin files for routers and level 2 for switches) is dealt with as a seperate physical machine.
This way you can:

create a network within one machine.
save up on memory as IOUs don't really take that much (64mb by default)
do any type of testing you need locally and for free.

iou2net.pl for instance is a tool you use to link an IOU instance to external networks.
This way you can use a real router/switch or network setting up the IOU either as one or a group or client OR your server itself.

Create a multicast router


Are there any established direct eigensolvers for sparse hermitian matrices?

Question: I have experience with LAPACK (direct solvers) and ARPACK (sparse iterative solvers), but are there any sparse direct solvers? I am concerned more with preserving space than with fast solutions. ARPACK is fast when it converges, but seems to struggle when many eigenvalues are degenerate.
Comment: There is a very fine line between direct and iterative in the end. Lapack's eigenvalue algorithms based on QR/Francis iteration are iterative, but so fast and effortless that they 'feel' direct. And even "direct" algorithms to solve linear systems like `DGESVX` include an iterative refinement step.
Comment: ARPACK is implementing $iterative$ solvers. It does not require or assume any sparsity.

IMHO, a better distinction is whether you need a subset of approximations to the eigenpairs (i.e. < n, the matrix dimension) or a complete set of approximations (i.e. = n, the matrix dimension).

- How many modes do you need?

- If you know the maximum size of degeneracy, then a block implementation of Arnoldi (or Lanczos) could handle the degeneracy.
Comment: @DJames A reference discussing these aspects is https://doi.org/10.1137/S0895479888151111
Section 4.5 discusses the block size: "[...] it is best to choose a blocksize as large as the largest expected multiplicity if eigenvalues of moderate multiplicities are expected. This is particularly important if many clusters of eigenvalues are expected (Table 12). A blocksize of 6 or 7 works well in problems with rigid body modes. We rarely find that p > 10 is cost-effective."
Comment: I suggest you provide the details of how you are using arpack. Among other things, it is not clear to me what you mean by direct and iterative "solvers".
Comment: @user7440 The number of modes is significantly less than n. Your comment on a block implementation is interesting. Could you expand on that?
Answer: There cannot be. The problem of finding eigenvalues is nonlinear, and it can be shown that finding eigenvalues of a matrix is a problem that is equivalent to finding roots of polynomials. We know that the latter only has solutions that can be computed in a finite number of steps for polynomial degree $\le 4$ in general. If there was a direct solver for the eigenproblem, it would also provide a way to find the roots of arbitrary-order polynomials.
In other words, any algorithm to find the eigenvalues of a matrix beyond size 4 must necessarily be iterative.


Can't make Gtk.TextView () fill whole parent Gtk.Box

Question: Can't make Gtk.TextView () hexpand. Only expands to like 2/3 of parent and wraps words too early.
Source: https://github.com/stsdc/monitor/blob/d3685a314712e263987da942724432c3469108e6/src/Widgets/ProcessView/ProcessInfoView.vala#L52-L61
Answer: A lovely application you built here, I particularly like the native indicator!
Looking into your Application.css:
.command_wrapper {
    background-color: #fdf6e3;
    border-radius: 3px;
    box-shadow: 0 1px 1px rgba(0, 0, 0, 0.12), 0 1px 2px rgba(0, 0, 0, 0.20);
    padding: 5px;
    padding-right: 190px;
}

In ProcessInfoView.vala (58:59), you are applying the 'command_wrapper' class to the command_wrapper Box widget:
var command_wrapper = new Gtk.Box(Gtk.Orientation.VERTICAL, 0);
command_wrapper.get_style_context ().add_class ("command_wrapper");

Commenting the padding-right: 190px line will result in the TextBox 'expanding' horizontally:

Also, I believe it is worth mentioning that in dark mode, the text in the TextBox is unreadable:
Comment: stupid mistake. Thank You. I will definitely add a dark style.
Also do You maybe know how to fix glitches when resizing the pane?


Dishonored - Daud's shared powers

Question: When Billie Lurk turns against Daud, if she were to kill Daud would that mean all of his assassins would lose there powers since they only have them because he shares them?
Answer: Although it is never explicitly mentioned there are several opportunities here. It could be the powers Daud's assassins have gained from him and through his training have become learned and do not depend on him being alive, this may at least be true for some of the basic abilities like Blink if not more advanced powers.
The other possibility is that Billie is able to gain power from another source, either from  Delilah who has a link to the outsider, or from the Outsider himself. Given his perchance for drama, the outsider would be most entertained if Daud were to fall to the hands of one of his closest allies and may reveal himself to Billie to offer her the same powers he did to Daud allowing the assassins to keep there powers under a new master.
If the outsider chooses not to reveal himself it almost certain the Billie Lurk would seek him out given her fascination especially if it now fell to her to lead and empower the other assassins.
This is all hypothetical by it is mostly inline with what we do know from the lore.
Comment: Interesting answer, I assumed the answer would be speculation, thanks a lot, I never thought about the outsider maybe marking Billie but it adds up, I doubt Billie would ask Delilah for power share since she turned the assassins in to the overseers. Thanks a lot.

Dishonored - Daud's shared powers


How can i connect the frontier template node to my Metamask on localhost?

Question: I tried connecting the localhost node by adding the port number along with the ip in Metamask the problem is with the chainId it shows error if i put any chain id in there and even if i define a chain id in chain_spec.rs and its still the same it says check your rpc url we cannot find chain id. Or something like that. So is it possible to connect to Metamask on localhost and if it is then how can i do it please leave some steps behind thank you.
Answer: You must configure your pallet-evm with a ChainId which will later be used by metamask to connect to your chain. After you've set up that and successfully run your node, you need to add the network to your metamask, along with the rpc port number and chain-id. Following these steps should give  you a metamask connection. Let me know if this works out for you.
Answer: Similar to what Purple_Turtle shared, here is a more verbose version, just find the section that talks about ChainID:
https://medium.com/@bernardoaraujor/nft-letter-substrate-frontier-73594b1424c
Answer: See this previous answer on StackExchange explaining how to include it, or change the Chain ID: How to connect substrate node to metamask?.
But per default the frontier template has a ChainID specified, you can try this:
pub const ChainId: u64 = 42;

Answer: Hey thank you everyone the problem was that i thought my chain was running on the port 9944 which in my case was not right so what i did was simply specify a port while starting the chain.


Late 70's or early 80's horror anthology?

Question: Trying to find the name of a late 70's or early 80's tv horror anthology show. One story I remember was about a baseball pitcher who loses his hand or arm in car crash and gets the arm of an executed murder. The pitcher then starts to get the urge to kill.
Comment: http://blackholereviews.blogspot.co.uk/2009/08/body-parts-1991-gory-horror-car-chase.html
Answer: It sounds like you're referring to the anthology horror film "Body Bags" starring Mark Hamill.
The third segment ('EYE') features a baseball player who receives an eye transplant and slowly evolves into a serial killer;

Brent Matthews is a Major League Baseball player whose life and career takes a turn for the worse when he gets into a serious car
  accident in which his right eye is gouged out. Unwilling to admit that
  his career is over, he jumps at the chance when a doctor tells him
  about an experimental surgical procedure to replace his eye with one
  from a recently deceased person which can restore his sight. After the
  surgery, Brent can see through his new eye, and is overjoyed at this
  miracle. But, soon after, Brent begins to see things out of his new
  eye that others cannot see, and it puts him and his wife Cathy in
  danger as Brent begins having nightmares of killing women and having
  sex with them. Brent seeks out the doctor who tells him that the donor
  of his new eye was a recently executed serial killer and necrophile
  who killed several young women, and then had sex with their dead
  bodies. Brent becomes convinced that the spirit of the dead killer is
  slowly taking over his body through his eye and enabling him to resume
  killing women. After Brent blacks out and wakes up near a crime scene
  where another young woman is killed, he flees back to his house where
  he tells the skeptic Cathy about what is going on with him. Just then
  the spirit of the killer emerges and attempts to kill Cathy as well.
  Cathy fights back, subduing him long enough for Brent to re-emerge.
  Realizing that it will only be a matter of time before the killer
  reemerges again, Brent cuts out his donated eye, severing his link
  with the killer, but he dies afterwards from bleeding to death.
Answer: Thanks, but I finally found out the name of the show. It was Quinn Martins Tales of the Unexpected(1977). The pitcher was played by Ricky Nelson.


In which section of the thesis should I give information about formatting? How?

Question: I am writing my Ph.D. thesis in mechatronics field. I used some notions from mechanical engineering and control engineering, but my work is mostly about a software solution. As the content is really multidisciplinary, it is possible that some of the readers do not know the even the basics of software-related practices. I want to inform them about the formatting of the text, for example an XML-element looks like <element>, or I have written a class name like Class. Where is the right place to do that? Introduction? And any examples how?
Comment: How about an appendix with the details, and a paragraph in the introduction about how you chose to present the software solution. Then, a short sentence can be used (as needed) nearer to any place you think the reader might need a refresher?
Answer: It is frequently the case that a scientific work will explicitly introduce its notational conventions to the reader.  Sometimes this is done inline, but if there is a significant amount to explain, it's nice to set it aside in an easily identifiable portion of the document with a name like "Notation."
If the conventions will be used throughout the thesis (as it sounds will be the case for you), then a good place to do this is following the introduction, either as a subsection or as its own chapter, depending on the size and complexity of what you write.


The Professors I want to work with are almost all in a different department to the one I want to apply to, is that a problem? This is for US unis

Question: I am in the process of contacting potential advisors at various universities, and finding out if they would be willing to take me on as a student, and then mention this in the application. However, I have run into a problem. The area of research I am interested in (desalination & water treatment) typically comes under the Civil and Environmental dept. in the US, and so do the faculty. Where I am from, this topic comes under Chemical Engineering. I have done my bachelors and masters in ChemE and want to do my PhD in it as well.
So now I would like to know if I mention that I want to work with professors from these departments in my ChemE PhD application, will it hurt my chances? Do I now have to consider applying to CEE Department instead?
Comment: This will depend very much on the particular university and its policies.
Comment: Are they listed on the ChemE department web pages as associated faculty? Not that uncommon. Perhaps there is a research center or center of excellence. If so, it would not be a problem at all.
Answer: If you have already made contact with some professors, seek their advice on the best way to do things. I think you are likely to find problems, however.
One solution you might suggest is to have more than one advisor, one in each department. This would be more likely to be acceptable to both departments.
The other issue is that if you have TA funding then it would probably come from the department you are formally associated with and they probably would want you to be a formal student in that department.
Good luck, but the best source of information and a solution is the professors you've already contacted.
Comment: (+1) This nails it. There are typically far fewer funded TA positions than applicants, the promised financial support is significant and multi-year, and departmental faculty do not want to de facto have TA slots used to support students who do not want to work with faculty in the paying department. That said, this kind of thing happens, but it gets scrutinized closely and the admitting department does not have to grant permission for its grad students to be primarily advised by grad faculty in other departments. At least that is how my department worked.
Answer: From my experience (US, biomedical engineering) this is actually quite common. There are many professors whose primary appointment is in a different department than the one you've signed up for. Again, from my experience, this actually tends to be a good thing; you get exposure to a wider range of faculty, students, collaborators, techniques, and ideas.
The specific department through which you're enrolled is mostly going to dictate your required course load, secondary degree-granting requirements (submission/publication counts, qualification exam differences), and possibly some thesis details. (Aside from the obvious "the actual degree you receive".) With respect to the first point—course load—I've found that departments are generally quite willing to work with you on non-core courses so long as its relevant to your work.
So to answer your specific question, so long as the professor is doing vaguely related work to your specific area of interest, I don't think it's likely to hurt your chances significantly. That said, this is something pretty specific to the university, so definitely just reach out and ask... this isn't an uncommon question.


Free todo software that allows repeat tasks both on given dates and on arbitrary timeframes

Question: I am looking for a free todo software that lets me set repeatable tasks both by date (1st of every month, January 1st every year) and more arbitrary timeframes (daily, seven days from prior completion, every 3 days). Preferably libre as well as gratis.
Answer: Not libre, but Google Keep allows you to create task lists with repeating reminders, which are synced with Google Calendar.


How might an ancient culture have discovered germ theory?

Question: In the real world, the germ theory of disease was only discovered in the 1800s, preceded by the theory of miasma and the four humors. Is there any way a civilization could have stumbled on this knowledge earlier, and what kind of environment/society is necessary for that discovery to take place?
Comment: The way people conducted science pretty much until the 1800s would've made this impossible, however: What the ancient Greeks (I'm sure amongst others) were good at was random guessing and sometimes not being completely wrong about it. Could've happened the same way
Answer: Depends on the definition of germ theory. Does it need a concept of single-celled bacteria and non-self-replicating viruses?

Start with a concept that dirt brings disease. They don't really ask why, it seems obvious.
Add the concepts that animals bring dirt if they are not cleanly/cleansed. Dogs are OK if they are washed regularly, rats are not OK. This includes insects. Bees are OK, they live in orderly hives. Fruit flies are not OK.
They note that there are big and small insects, from butterflies to lice. Lice range in size from 5 mm to 0.5 mm. Their eggs are smaller.

If a society concludes that there is no minimum size to disease-bearing insects, does that mean they have a germ theory?
Comment: I'd say guessing right counts for my purposes. This line of thinking might even lead scientifically-minded members of that culture to test the theory and discover microbes once the right tools are available.
Comment: This is a delightfully clever way to have something *like* germ theory without any real vigorous science to back up the notion.  Definitely the sort of thing a very primitive culture would come up with and innately understand.
Comment: That is basically how germ theory formed anyway. Germ literally referred to tiny eggs or spores. What germs are was only discovered much later.
Comment: This is a good point - is it "discovered" if they guess the right answer?
Answer: They'd need:

A culture of curiosity.  (Islamic Golden Age or Europe starting with the Renaissance.)
Knowledge sharing (aka "science") instead of researchers who horde their knowledge (aka "alchemy").
A concentrated-enough energy source to have:
Sophisticated metallurgy and metal-working, and
sufficiently developed glass-making, which leads to
Optics, which leads to:
Microscopes.

EDIT: good ideas from user535733:

Mathematics developed enough to have created statistical analysis.
Enough wood/bamboo to make lots of cheap, durable paper.
The industrial chemistry to whiten that paper, and
make lots of ink, for
Printing the results of epidemiological studies in Journals. (Another need for "knowledge sharing").

Bottom line is that the ancient culture won't be very "ancient".
Comment: Consider adding statistics and data management to the list - epidemiology provides clues where to start looking. That also means cheap-enough paper (and perheps printing) to store the data and transmit the knowledge.
Comment: @RonJohn Hold it right there... the Germ Theory of Disease does not require us actually **seeing** bacteria or fungus or anything like that. Seeing the pathogens only makes us understand the mechanics of the theory in an intuitive way, but the theory that there is something communicable that transmits disease do not require seeing them. In other words: **you do not need Microbiology to work out The Germ Theory of Disease**, that only makes it easier. Compare for instance Maxwell's Equations and the Theory of Electromagnetism... you do not need to physically see a photon to work that one out.
Comment: @MichaelK On the contrary it does. Pre-germ theory ideas did involve contagion. Why else did they believe in miasma (especially)? That was in essence a theory about contagion. They needed to see & know the microbes were there. I'm sure historical research into how Semmelweiss came up with germ theory would confirm it
Comment: 9. isn't necessary I reckon but the rest of that seems right (although not quite *as* modern as you think)
Comment: Microscopy enabled scientists to observe microbes. That enabled the idea to be formed that microbes could be the source of disease. Good answer because you established the steps necessary for the development of microscopes. Plus one, and deservedly so.
Comment: @a4android thank James Burke's 1978 TV series *Connections* for the idea.  We could drill this down for a week, expanding the list of dependencies upon dependencies.
Comment: I was also thinking of James Burke when I wrote my comment.. I have the book of the series too. Seeing microbes enable the connections to be made. *Viola!* germ theory!
Answer: I've read a number of medieval medical treatises (for fun!). These writings tend to combine classical information, some practical experience, and random bits of info. I always get the feeling that they were so close to getting it. Cleaning hands before procedures is mentioned more than  you'd think. The effectiveness of wine for cleaning wounds is remarked on in a medieval military medicine treatise. Of course there is crap (literal and figurative) mixed in with the useful stuff and a new practitioner coming upon the treatise has no way to judge.
In reference to @RonJon'a list Optics as a science did fairly well in the Middle Ages. Spectacles receive their first mention in the mid 13th century. Clockworks with gears start appearing in tows around that time as well.  Paper as well though you could use wax tablets for note taking. (I just spent an hour collecting oak galls from fallen branches to experiment with medieval ink recipes.)
The sharing of good information is of course a limiting factor. Medieval Europe knew how to hold a conference, they did that all the time for Church Councils, but there was little will for a natural science conference.
A plausible way for this germ theory information to spread in a 13th century environment would be through a military campaign. A secular ruler would have a very good reason for useful information to be shared and used on his (elite) soldiers. As the physicians return home they'd spread this knowledge.
I'm not sure if the Middle Ages is ancient enough for your question for it is my lens of information.
Answer: People and their livestock have pests including those that make them (and their animals and crops) "sick".  People discover poisons to deal with them.
Some pests are tiny.  In particular, some mites or aphids or other important pest for agriculture has two properties: it makes the crops wither rather than just looking chewed, and it's so small that it's near the limit of human vision: some people can see them, some can just barely notice dots if they are moving, others cannot see at all.  And clearly the juviniles are too small to see.
So, people are aware of the idea that animals can be too small to see, with no known limit to how small they may become.  And they are known to be some diseases.
Since the same idea of hygene and steralization seems to work to prevent disease, and that's how cleaning and killing tiny pests works.  So it would be a hypothesis that many more (if not all) diseases are caused by pests too small to see.
Answer: I'm not sure whether it counts as theory, but there seem to be some psychological mechanism in religion development that mixes up goodness, religious purity and cleanliness.
I mean Baptism in Christianity... Ritual washing in Islam before prayer... Or Hindus that pilgrimage to wash in Ganges...
Yeah, there really seems to be some kind of automatic association.
If you want to have an ancient society that get such theory roughly right:

they have to have some vague commandment concerning cleanliness and purity
they should suffer from some parasitic disease and think in this direction

(But it would be like Democritus atom hypothesis - guess in good direction, but not based on any hard data https://en.wikipedia.org/wiki/Democritus#Atomic_hypothesis)


Magento 1.9.1 Cron Jobs

Question: Is it possible not to use the cron jobs to send my sales confirmation email? I am on a shared hosting with hostgator and they don't allow cron jobs to be less than every 15 minutes. I don't want my customer to see an order confirmation after 10 or 15 minutes. IS there a way to change this?
Comment: I see no reason on why they should put such archaic limit in place. One better way is to consider another provider who allows you to set a shorter interval for your Cron Jobs.
Comment: Shared hosting really isn't cut out for Magento, whatever the hosting provider might tell you - would really recommend you upgrade to VPS or better.
Comment: Thankyou for the suggestion
Answer: Well, if you don't want to jump hosts, just set up multiple entries in crontab which do the same thing and are offset by the frequency you want the mail sent out.
But, really, this is an indication of a host which is not well-suited for Magento.
Comment: This might sound stupid but do you mean in my hostgator cpanel - cron jobs? or in my cron.php file?
Comment: I went to my hostgator cpanel and offset the time to */15+5 in the minute, it says "Cron field not formatted correctly."
Comment: If you want Magento cron executed every 5 minutes, then (given the 15 minute limitation) you can try `0,5,10,15,20,25,30,35,40,45,50,55 * * * *`. Or you can specify each entry individually if that doesn't work.
Comment: Cool! I did one job with */15 (every 0, 15, 30 and 45). Made a second one with 5,20,35,50 and a third one with 10,25,40 and 55. Everything works! so far so good, they have not removed it yet! Thanks for the tip
Answer: I'ts possible to achieve that by modifying the Magento Core.
In the class Mage_Core_Model_Email_Template you can find the method send(...) in around line 371, and inside this method, find this line:
$subject = $this->getProcessedTemplateSubject($variables);
in my version its in line 392, there you can catch the content of the email in $text and the $subject, and send the email using PHP's mail() function.
I admit that this is not a clean way to do that, but this will fix the issue.

Magento 1.9.1 Cron Jobs


Can two iPhones access the same iCloud content?

Question: My wife and I have iPhones. We have separate Apple accounts on the phones. Can we share the same iCloud music and pictures?
Comment: iCloud PhotoStream sharing is an announced feature of iOS 6.  It's weeks away.
Answer: Nope. The same account would need to be signed in on both devices.
Answer: You would need to both use the same iCloud account in order to share photos across Photo Stream. You can sync both devices with the same iTunes library to share music, while still using seperate Apple ID's within the iTunes store under the phone settings. (if you wish to continue using separate IDs for downloads)
iCloud does not sync music, so if the end result is to share all music downloads and photos the best advice I can give is to stop using one Apple ID and simply start using the same ID. There is no way to merge two IDs, only to both share the ID that contains more downloaded music and apps.
Answer: Now it's possible:
You can set up shared albums on iCloud for pictures, and Family Sharing for music bought on the iTunes Store; you can also subscribe to a Family Plan on iTunes Music.
Answer: If you have a shared account for iTunes and individual accounts for Mail/Calendar/etc. it is possible to access iCloud music from several devices. Just make sure to log in to iTunes with the shared account on both iOS devices (and on the Mac).


What is the point of the `cd` external command?

Question: As referenced in this fine answer, POSIX systems have an external binary cd in addition to the shell builtin. On OS X 10.8 it's /usr/bin/cd. You can't use it like the builtin cd since it exits immediately after changing its own working directory. What purpose does it serve?
Comment: My Fedora 19 includes `/bin/cd` however.
Comment: Debian (I checked several releases, including current testing) has neither `/bin/cd` nor `/usr/bin/cd`.
Comment: I guess that makes these systems not strictly POSIX. Just like everyone else. :)
Comment: Note that Ubuntu and CentOS (and therefore presumably Red Hat) don't have `/usr/bin/cd`, only the shell built-in.
Answer: It serves primarily as making sure the POSIX tool-chest is available both inside and outside a shell (see the POSIX rationale for requiring those).
For cd, that is not tremendously useful but note that cd changes directories but has other side effects: it returns an exit status that helps determine whether you're able to chdir() to that directory or not, and outputs a useful error message explaining why you can't chdir() when you can't.
Example:
dirs_i_am_able_to_cd_into=$(find . -type d -exec cd {} \; -print)

Another potential side-effect is the automounting of a directory.
On a few systems, most of the external commands for the standard shell builtins are implemented as a symlink to the same script that does:
#! /bin/sh -
"${0##*/}" "$@"

That is start a shell and run the builtin in it.
Some other systems (like GNU), have utilities as true executable commands which can lead to confusions when the behavior differs from the shell builtin version.
Comment: +1 for the observation about side effects and error messages. It is not always well explained to new users that a lot of clever idioms in Unix come from careful use of side effects. And the man pages themselves have never been good at describing the bigger picture.
Comment: @ffledgling, see https://en.wikipedia.org/wiki/Automounter
Comment: To unpack Stéphane Chazelas's thought a little: if you need to ensure that an automoutable directory is in fact mounted without making any changes on it and without making an attempt to read any files, you could use the external `cd` command. Might be useful in monitoring the availability of an automountable remote filesystem, or perhaps before doing something time-critical with one.
Comment: Came here from a similar question on SO, could you elaborate what you mean when you say "automounting of a directory" ?
Comment: "without making any changes on it" - It may update its access time if that option is enabled in the filesystem.
Answer: The fact a non builtin cd command is available is essentially due to the POSIX requirement for all regular builtins to be callable by the exec family commands env, find, nice, nohup, time and xargs combined to the fact some of these commands are not being themselves implemented as builtins.
That doesn't make much sense for cd though as combining it with these commands is quite pointless. Here are more or less tenable examples though:
find . -type d -exec cd {} \;
env HOME=/foo cd

Comment: @Kevin I wrote it is a requirement for all **regular builtins**, the exempted ones are **special builtins**: `break, :, continue, . , eval, exec, exit, export, readonly, return, set, shift, times, trap, unset` would be irrelevant as external commands while `cd` is a regular builtin that has some documented use cases as a command.
Comment: A number of built-ins are actually [exempt from that rule](http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_14).  Bizarrely, cd is not one of them.
Answer: In addition to checking whether a path corresponds to an accessible directory, the cd executable will process and use the CDPATH variable, and will print out the absolute path of the resolved directory if it was used successfully.
$ export CDPATH=/usr
$ echo bin lib | xargs -n 1 cd
/usr/bin
/usr/lib

This is only very occasionally useful, but would save reimplementing the same logic for searching for matching directories. A concrete use case is finding the first existing directory of a particular name under several possible parents.
cd also processes OLDPWD for cd -, but that is less concretely useful since the environment variable would already be available.


The role of maps in algebraic structures?

Question: In group theory we have encountered the concepts of homomorphisms as maps from one group to another, and the same thing with ring and field theory and we ave called them respectively homomorphisms of groups (of rings, and of fields). Also in linear algebra we have linear maps.
So my question is this:
What is the role of such maps in this algebraic structures?
Comment: Congratulations!  You have just discovered category theory!
Comment: Relevant: http://en.wikipedia.org/wiki/Morphism
Answer: One of my professors once said this about ring theory:

To study rings, you have two choices. You can take a particular ring, and stare at it intently for a long period of time until you discover interesting things about that ring. Then you write them down.
Or you can study how the rings "acts" on other structures, by studying the collection of all modules on that ring, and thus deduce interesting things about the ring. It turns out that the latter method is more fruitful, easier to generalize, and allows one to go from one ring to another ring more easily.

Studying the modules of a ring can be seen as a special case of studying homomorphisms (an $R$-module structure on an abelian group $A$ is equivalent to a ring homomorphism from $R$ to the endomorphisms of $A$, which are a ring under pointwise addition and composition. (Which is why I mention it)
The example of vector spaces is very apt. Vector spaces are nice objects,  no doubt; but if all you do is stare at a particular vector space, you can say some interesting things (dimensions, subspaces, and so on), but it's not until you bring in linear transformations that the full power of vector spaces really becomes apparent. It is through linear transformations that we can actually do things with vector spaces: use them to solve systems of equations (linear and differential), to study Markov systems, to solve least squares problems (which amount to constructing certain kinds of projections, which are types of linear transformations), etc.
There is a whole philosophy of mathematics that says that the best way to study objects is to study the maps that "respect the structure", and not only for algebraic objects: topology is not just the study of topological spaces, it's the study of topological spaces and continuous maps between them. Analysis is not just the study of the real numbers, it is the study of the real numbers and real valued functions. Differential geometry concerns itself with differentiable maps. Etc. Turns out that maps give you a fruitful way of studying the structure.
In algebra, an important role is played by "congruences", which are equivalence relations on the underlying set that are compatible with the operations. For example, in the ring of integers, the usual modular congruences, $a\equiv b\pmod{n}$, give an equivalence relation that "respects" the ring structure on $\mathbb{Z}$, in the sense that if $a\equiv b\pmod{n}$ and $x\equiv y\pmod{n}$, then $a+x\equiv b+y\pmod{n}$ and $ax\equiv by\pmod{n}$ (the sum of classes is the same as the class of the sum; the product of classes is the same as the class of the product). Congruences correspnd, via the isomorphism theorems, to surjective morphisms.
Morphisms let you take one particular structure and study it from other points of view, in other contexts; it allows you (via "quotients") to focus on particular details while ignoring other part of the structure that may be "in the way" (e.g., the study of "parity" is made simpler by considering the quotient $\mathbb{Z}/2\mathbb{Z}$, rather than $\mathbb{Z}$ itself).
Morphisms let you understand inherent symmetry in an object; Klein proposed studying geometry almost exclusively in terms of certain kinds of symmetries and certain kinds of morphisms (projective transformations). Galois theory is founded on the idea of understanding the "symmetries" that may exist between different roots of the same polynomial (in the form of automorphisms).
All in all, morphisms are just a very rich way of studying objects. You can think of them as a way of letting you poke, examine, cut open, x-ray, fold, and generally manipulate your objects of interest so that you can get a better sense, not only of what they are, but how they interact with other objects and other contexts.
Answer: Homomorphisms do a lot of things:

They can be used to show two structures are identical (isomorphism)
They can be used to show one structure is a substructure of another (monomorphism)
They can be used to show one structure is a quotient of another (epimorphism)
General homomorphisms are kind of a mixture of the above, carrying a certain amount of data about the relationship between the domain and codomain.

This list is not exhaustive, it's just meant to sample some of what homomorphisms do.
Comment: Any homomorphism of [groups, rings, modules] is an epimorphism followed by a monomorphism, so it is a **precise** mixture of the above. In general, I think any morphism in an abelian category is an epi followed by a mono, but I don't know if this condition on the category is necessary or not.
Answer: Groups, rings (especially fields) and many other objects in mathematics form so called categories. I.e. the collection of all rings (whatever this is) forms a category. To 'compare' the objects in a category, one needs morphisms between them. (This is not the only need for morphisms, but one of them). To say that one object is 'bigger' or that two objects are isomorphic, one needs the notion of morphism.
Morphisms are generally maps (though not all morphisms need to be maps) that respect the structure of the objects.
Of course, morphisms have other useful applications. Matrices for example (i.e. morphisms of vector spaces [or modules]) are connected to linear equations and so on...
Morphisms play very many very important roles in mathematics :)
Answer: Another function of morphisms is as a way of taking an unfamiliar or apparently complex algebraic object, and placing it in a more familiar context, or one where there are known analytical tools and methods - as in representation theory.
The point of view you take depends rather on whether you are more interested in studying particular objects, or alternatively classes of objects.
Answer: Let's suppose for the moment that you really only care about isomorphisms. That is, you really only care about telling whether two groups are isomorphic, or something. Great! But how do you write down isomorphisms? It's hard. Often you will be able to write down a map and you'll want to show it's an isomorphism. Before you show it's an isomorphism, what is it?
It's probably a homomorphism!
So even if you only care about isomorphisms, in the course of proving things about isomorphisms you will very likely end up having to talk about homomorphisms which are not necessarily isomorphisms (at least you don't know that they are), so you might as well talk about them from the outset. Moreover,

you can use homomorphisms to construct isomorphisms,
even homomorphisms which are not isomorphisms can be used to prove useful statements, e.g. that there do not exist certain isomorphisms,
etc.

But really to understand this you should do a lot of mathematics. It will become clearer to you as you gain experience with working with maps.
Comment: +1 for "even homomorphisms which are not isomorphisms can be used to prove useful statements"
Answer: I think the use of homomorphisms is to identify one algebraic structure with another. With that identification we can say that two algebraic structures are same structurally i.e they are same when we view them with respect to algebraic operations involved in them although they may seem different with open eye.
Comment: Certainly not. Almost all homomorphisms I work with are not isomorphisms. Homomorphisms which are not isomorphisms are hugely important, such as in homology and cohomology theories.
Comment: So all groups are the same with respect to algebraic operations to the trivial group, due to the trivial homomorphism? I think you are talking about isomorphisms rather than homomorphisms.
Comment: @AlexBecker: Yes I am talking about isomorphisms. I think the major use of homomorphisms is through isomorphisms.
Comment: @AlexBecker: Sorry, I did not know that, I have not gone that far in algebra.


Does Проходите really mean come in?

Question: In  a dialogue from Langenscheidt's Praktisches Lehrbuch Russisch guests are greeted with "Проходите", translated as "Come in" ("Kommt herein").
Is that usual in contemporary Russian for telling someone to come in?
Dictionaries seem to translate "Проходить" as "to move on", "to pass", etc.
Comment: It's a colloquial way to say "come in".
Answer: Yes, проходите can be used to say "come in". It is short form for "проходите в дом". Usually when you visit an official person (or a person in an office, or a doctor) you'll have the following dialogue:

-- К вам можно?
-- Да, проходите, садитесь.
― Да-да, входите, Тамара Владиславовна, ― изображая дружелюбие, закивал Глебский. ― Проходите, садитесь. [Петр Акимов. Плата за страх (2000)]

Also a policeman can say "пройдемте" which is short version of "пройдемте со мной в отделение милиции".

In fact Словарь Ефремовой lists 14 different meanings of the word проходить, including the one Eugene mentions.
Comment: Проходите literally means 'come through'; it is primarily used in situations where you pass the object you are invited to go through quickly (say, airport metal detectors). It *could* be used to mean 'come in' - like the situation you described, however 'заходите' or 'входите' sound more natural to me.
Comment: I find your and Eugene's answers equally satisfactory (thanks to both!), but since Eugene's reputation is so far below your  stellar one, I will accept Eugene's.
Answer: Проходите literally means 'come through'; it is primarily used in situations where you pass the object you are invited to go through quickly (say, airport metal detectors). It could be used to mean 'come in' - like the situation @Artemix described in the other answer (in the case with дом, the 'object to come through' could be a corridor or a hallway), however 'заходите' or 'входите' sound more natural to me.
Answer: Has a weak polite scent, translated as "Come in" in this particular case. But Проходите мимо will be Pass by, for sure. Also, can even be translated as Take your seats (Займите места).
Depends on situation and voice intonation. Merely, it is used to tell a person to move where he is mostly expected to go. For example, if a fireman officer tells you Проходите, he really means Don't stop there! But if you tell your girlfriend Проходи kindly, then you definitely mean You are welcome, darling.
Answer: It can be translated as come in. Literally, it means: come through. Come through is used, not "when you visit an official person", as was stated in one of the posts, but it just means as you are passing through the doorway.

Does Проходите really mean come in?


Diagnostic plot (residual vs. predicted) of a glmm using DHARMa

Question: I used glmmTMB to fit a model with beta distributed errors, zero inflation, several nested random effects and temporal correlation. I then used the diagnostic plots available in DHARMa. My residual vs predicted plot looks like this
The plot is (I think) similar to the one shown in the other packages section of the DHARMa package vignette. What is the meaning of the dashed line? Also, are all three residual lines overlapping at 0.50?
Answer: I just found that the question has been posed before and answered here
Quoting Florian Hartig's response:

Hi, this is expected behavior - the default of the plot function is to
  do the quantile regression for n <= 2000, and for larger datasets a
  nonparametric smoother, because the quantile regressions can take a
  long time to calculate. You can overwrite this if you want. Example
library(DHARMa)
testData = createData(sampleSize = 2200, family = poisson(),
                        randomEffectVariance = 0, numGroups = 5) fittedModel <- glm(observedResponse ~ Environment1,
                     family = "poisson", data = testData) simulationOutput <- simulateResiduals(fittedModel = fittedModel)
plot(simulationOutput) # default switches to quanreg = F for n > 2000
  plot(simulationOutput, quantreg = T) # overrule default
side note: with so many data points, and binomial, it would be useful
  to think about if you can group your data in some way, using the new
  recalculateResiduals() function in DHARMa 0.2.0
Comment: The answer is still good, just an add-on: there is a new DHARMa version with a more efficient quantile regression available for beta testing, see https://twitter.com/florianhartig/status/1227291704371269632
Comment: I am not sure if this should be an answer or an update of the original post. Please advise.


How does the number of eggs affect a cookie recipe?

Question: If a chocolate chip cookie recipe calls for two eggs and I add three eggs, what will the effect be on my cookies?
Likewise if it calls for two eggs and I only put in one egg what will the effect be?
Answer: Eggs contribute to better texture, leavening and they extend shelf life. More eggs = moister (sp!) cookie. Eggs are also crucial in building structure. They are about 75% moisture, 12% protein, 10% fat and 2ish % sugar.
The white provides strength, stability and moisture.
Yolks, where all of the fat is in an egg, increase richness, tenderness and flavor.
Therefore, if you put an extra egg, you will get a chewier cookie. I do it all the time. If you put less, you will get a more crumbly cookie.
Comment: Another trick is to use extra large or jumbo eggs, even though most recipes call for large. There is only about 10-15% more egg 'stuff' per egg, but it can make your baked goods a little moister without making the dough too gooey.  My mother does this all the time, and we all know Mom's cookies are the best.  I usually just have large eggs around the house for various reasons, but using larger eggs has never been a problem in my experience.
Comment: My take is that eggs will promote a SOFTER cookie, not necessarily a CHEWIER cookie. Soft cookies and chewy cookies are not the same. Soft means a slightly more cake-like texture. Chewy has more substance to it; takes longer to chew! Neither is crumbly or hard. I wonder if others agree.
Answer: I think if doubling the batch of chocolate chip cookies, one should also add egg whites to lend stability and hold cookie together.  Too few eggs will make dough crumbly.
Answer: The more eggs, the more cakelike a brownie or cake recipe will become.
The less eggs, the more moist and dense it will be.
Eggs cause fluffiness.
Comment: and generally in cookies, flour contributes to a cake-like texture.  Whole eggs generally make a cookie chewier.
Comment: Nope. Whipped egg whites (or even whipped whole eggs, to some degree) add fluffiness, sure. But just stirred/beaten into the other ingredients? They add fat and moisture, and they're not adding any air. They're not going to make a cookie fluffy.
Comment: @LarsViklund Yes, it starts with "wrong" and obviously was replying to something. But it also makes a specific claim about what the answer to the question is (eggs make things cakelike and fluffy), so it is also certainly an answer.
Comment: This is not a forum, answers should be standing on their own ground to the original question, not interjections against other answers.
Comment: Perhaps editing to remove the "wrong" portion would be appropriate? That would make this a stand-alone complete answer. pdavidson could then separately "Reply" with a Comment to the answer he thought was "wrong".


What are obsolete effects?

Question: I'm trying to make an animated slideshow in Premiere Pro, and the examples I've found on the net all use the motion effect. However I noticed that it doesn't do anything, and I noticed it's in the obsolete folder. There are a bunch of other effects in that folder, does that mean that they don't work anymore?
Answer: I think it means that they've been replaced by other in house effects made by Adobe which work better (ie less processing/rendering needed to create the same effect).  Adobe tends to keep the old versions around for backwards compatibility in case you need to open an old project.
This link is to After Effects, but it's the same issue:
https://helpx.adobe.com/after-effects/using/obsolete-effects.html

What are obsolete effects?


Ontario New Home Tax Rebate

Question: I've been doing a lot of research on the new home tax rebate. There is a house we want to buy, listed with a realtor - the seller who owns both the land and the house is a builder (he bought the land & built the new home). The house is priced at $399 500, and the listing says HST is included.
I have calculated out what the new home rebate should be, given that 399 500 includes HST (so the actual price of the house would be $353 ish... but when we talked to the builder he said he wants the buyers to sign over the rebate to him, and that the tax rebate is only around $8000. Not according to my calculations (I thought the max rebate for HST is 24000?).
He said that he received the tax rebate since he paid tax on everything he bought for the house (ie. counters, flooring etc.)... but to me I figured that's what HST included meant - that we would be paying for the taxes. Would we have to sign this over to him? I'm so confused!
Thanks for your help!
Answer: I wouldn't sign over any rebate to the seller as the rebate was intended for you as the buyer. Your best bet is to negotiate the final price of the house with the seller and then, if you are happy, legally buy the house. Whatever rebate you get will be yours.
If the seller feels that he should get the $8K rebate then you should reflect that in the sale transaction (and price) not in a backroom deal.
Answer:
Would we have to sign this over to him? I'm so confused!

I think your lawyer and your realtor should be able to answer this question.
Answer: I think your builder is referring to the "GST New Housing Rebate". Here is a page that talks about it. Here are a few salient points:

New home buyers can apply for a rebate of the 5% GST ... to a maximum of $8,750 for homes costing less than $350,000 before GST.
In the Greater Toronto Area (GTA), most builders include the GST in the price of the house, and any rebate would be assignable to the builder as they would be absorbing the net GST cost.

It looks as if your builder is telling something like the truth. It's not because he paid the tax on the construction materials, but because he has agreed to pay the tax on the house purchase for you. Importantly the rebate is only for the federal (GST) portion of the sales tax, which probably accounts for the 8000/24000 difference. However you should probably check with a realtor (and not the one your builder is using).

Ontario New Home Tax Rebate


Measuring broadcast message latency using system clock, good idea?

Question: I want to measure broadcast message latency over our message broker on a 1GB LAN.
Messages are transmitted in a pub sub fashion, one publisher, many consumers.  The producer timestamps each message using the system clock (DateTime.Now in C#) and consumers measure latency by subtracting the timestamp on the message from DateTime.Now.
<code> double latency = (DateTime.Now - msg.NMSTimestamp).TotalMilliseconds;
</code>
All of the boxes on our LAN sync their time via NTP once an hour yet I'm seeing significant latency and even negative times in the range of +/- 1 second.  I read that NTP should provide ~5ms accuracy in a LAN environment.
Is my measurement strategy fundamentally flawed? Is there another explanation for the negative latency?  If I was only seeing large latencies I'd suspect our message queue was slow but the negative ones really have me confused.
Comment: are your clocks all synchronized to one server?
Comment: yip, all syncing against the domain server
Answer: What are your negative values looking like in millis? If it's within 5ms, that's normal for NTP, as you know. There could even be up to 10 millis difference between computers if one computer was 5 millis ahead of true time and another was 5 behind. More than that, I would guess that there's some rounding error, lookahead/lookbehind error, or sync errors somewhere in your system. There are many hardware and implementation details you have little control over that can produce inaccuracies. GENERALLY, system clocks are accurate enough at the millisecond level when polled by DateTime.Now, but many hardware details like CPU throttling under load, pipelines, cache thrashing etc. can introduce enough error to be significant at the millisecond level.
If possible, set up your computers to synchronize with the NTP server at least a second apart form each other. If all computers try to sync on the hour every hour, the NTP server will be flooded, increasing inaccuracies in reporting the correct time due to crowding and packet scheduling. I think this is the most likely cause for what's going on. Also, make sure your network is as efficient as possible, by reducing cable runs (300ft is the theoretical maximum, and in an EMI-noisy environment runs as short as 40 feet can cause serious problems), replacing hubs with switches, and minimizing wireless network use.
Comment: very interesting.  I'm seeing a difference of +/- 1000ms though across the network
Answer: I have a handful of incidents logged of negative network latency measured by the same clock.
Windows fails to implement clock skew, so you see these whenever a sync happens.
Windows does not guarantee 5ms accuracy, but only 18.2 ticks per second. My machine provides an epsilon of 15ms.


Does anybody actually use "scenes"? if so, what are some good/typical use cases?

Question: What can I use them for? Some concrete examples. I feel like I might be missing out on something.
Comment: There are a lot of ways to use scenes, you probably want to keep objects there to use in another scene or use a different render engine to achive something concrete, you may need to experiment to see the things that you could do. Examples are a lot in youtube, here is one that is mine :https://youtu.be/9ey7KtNrXDQ
Comment: You might want to start by reading the manual page: https://docs.blender.org/manual/en/latest/scene_layout/index.html
Comment: @Emir, thanks. So a day and night variants of a project is one use case. Good.
Comment: @susu - Thanks. I am familiar with the scene functionality. I know what it does. What I wanted to know were examples of HOW one could make good use of it (use cases)
Answer: Not sure how much help this will be but I'll share my experience anyway. A usage that has worked well for me is as follows -
I been using Blender in place of an architectural CAD package to design a small summerhouse. I have a main scene in which all the elements are drawn (slab, landscape, sole plate, studs etc.) and these are all placed into collections in that scene to help organise them and manage visibility.
If I now want a drawing of a particular subset of these elements, I can now create a scene for it and link in the elements I want to show on that particular scene. The linkage can be by collections but it is also possible to link in individual elements from the master scene. I can now create a new collection in that scene for the elements that are to be present only in that scene; into this local collection I place a camera and possibly lights and adjust the scene settings to use this camera for renders. I also set the camera to be isometric to get a plan view, use freestyle to render the line edges and add dimension text to the scene local collection and use material override to render all objects in a plain grey material. I can now render this out and effectively get a plan view line drawing.
This now means that I can return to the main scene and continue to add elements to it and, as long as I'm carful about keeping things in the right collections, these new elements will also be visible in the other drawing scene (if that scene links that collection). The main scene still has its own camera and renders from this scene will be in perspective and with materials rendered.
This workflow loosely recreates the feature in CAD packages where you can have a number of drawings with different views and subsets of the main model. In my workflow, each scene is a drawing.
This is possibly not what the scenes feature was primarily designed for but I do find it it useful in this case.
Comment: Ah, I see. So it's useful for architectural and design purposes. Thanks.


how to mathematically prove a key exchange algorithm

Question: I want to know the basic methodology that can be used to prove that a key exchange algorithm is secure. I am not asking about any specific algorithm. I want to know what should be proven and how to prove in an abstract way.
Comment: Welcome to Crypto.SE!  Unfortunately, this question is probably too broad and open-ended to be a good fit for this site.  What have you studied so far?  What's the real problem you have in front of you?  What's the context and motivation for your problem?  Providing a more detailed and narrowly focused question makes it more likely that it will be possible to provide a useful answer, within the constraints of a StackExchange site.
Answer: I guess the best place to begin is with the paper that started it all: Entity authentication and key distribution, by Bellare and Rogaway. In a nutshell, they define a protocol to be a secure mutual authenticated key exchange if it fulfills the following four criteria (I will explain the term "matching conversation" below):

Matching conversations $\Rightarrow$ both parties accepts, meaning that both parties believe they are participating in an authentic session. Note that this is criteria is basically a simple "sanity check" of the protocol: if there are no adversaries the protocol should "work".
If a party accepts $\Rightarrow$ there should exist some matching conversation out there. This is the first "real" security requirement. What this basically says is that a protocol provides secure mutual authentication if all that an adversary is able to do is act like a wire between the protocol participants. An adversary which faithfully relays all protocol messages between the parties is called a benign adversary.
Benign adversary $\Rightarrow$ both parties obtain the same key and in accordance with the distribution chosen for the key space. Again, this is basically a sanity check of the protocol.
Session key is protected. This means that if the parties managed to agree on a shared key, the attacker should not be able to learn anything about it. This is formalized by a game between a challenger (one of the parties) and the adversary, where the challenger gives the adversary either the real key or a random string (from the same distribution). If the adversary is not able to distinguish these two settings, we say that the session key is protected.

Thus if you are to prove a key exchange algorithm secure you need to show that it provides the four points above. Usually you do this using a reduction to an underlying assumption, like the existence of secure encryption functions and MAC's. The term matching conversation means that if party A sent out ($\alpha$) and received ($\beta$) the following messages: $(\alpha_1, \beta_1), (\alpha_2, \beta_2) ... (\alpha_n, \beta_n)$ (in that order), then B have a matching conversation if he received ($\alpha$) and sent out ($\beta$): $(\alpha_1, \beta_1), (\alpha_2, \beta_2) ... (\alpha_n, \beta_n)$ (in that order). There are some more technicalities to this definition dealing with who sent the first message and so on, but the gist of it is that A and B have matching conversations if they received what the other party sent out (and in the right order).
Note that this is only one approach to this subject and is by no means the right way of defining a secure key exchange. Another common approach e.g. deals with a simulation framework of interactive turing machines, and proves that a protocol simulates an ideal functionality defined in this model. These are in some sense much more elaborate and complex than the simple approach given by Bellare and Rogaway, but are also much more general.


Mixamo Rig Blender Bone Naming Convention

Question: Mixamo names bones as mixamorig:LeftForeArm for example. For reasons, I need my bones to end in .L and .R to stick to Blenders naming convention so that I can more easily make other changes. Does Mixamo allow this?
Answer: I don't think that you can change this in Mixamo. But you can...
Batch Rename Everything in Blender:
Select the armature, switch to Edit mode. Select all bones, and press Ctrl+F2 or select the menu entry Edit > Batch Rename... of the main menu. In the popup panel:

Restrict the search to Selected and the object type Bones
Find: ^Left(.*) and click the regex button *
Replace: \1.L and click the regex button *

Note: you need to use \1 for the regex groups, not $1 as described in the linked wikipedia article.
This renames every bone which name begins with Left and replaces it with rest of the name.L. All left bones are renamed. Repeat the steps for the other right side with adjusted values and it's done.
Comment: Hey I forgot I asked this. It works for me. Thanks!


can i put hot soup in mason jar for travel

Question: i ran out of glass containers (people haven't returned them) and i want to give my boyfriend hot soup for work.  Is it safe to put it in a mason jar and put the lid on while hot? And how long might the soup stay hot in it?
Comment: why not take your bf soup in a thermos cup?
Answer: I have had mason jars break when filling with hot items.  It is best to warm the jar first, just by running hot water into it.  A someone else pointed out, a mason jar is, of course, not insulated.  You mention this is to take to work, I assume for lunch or dinner.  I also want to point out that you need to consider food safety, as your soup will soon be in the "danger zone."  You should read this.  It is much safer to chill the soup to refrigeration temperature, pack it in a cooler, or refrigerate at work, then reheat at meal time.
Answer: For the first part, about pouring hot soup in mason jars, it should be safe, but there's always a risk of shattering if the liquid is too hot.
There are many somewhat related topics regarding putting hot liquid in mason jars.
Is it safe to put fresh hot soup in a glass mason jar?
https://www.reddit.com/r/NoStupidQuestions/comments/9rd3y2/will_a_mason_jar_explode_if_i_put_it_into_boiling/
https://www.quora.com/Will-a-mason-jar-shatter-if-I-pour-hot-water-in-it
...
For the second part, It will not keep the soup hot/warm for a long time, it is not a "thermos" container.
Comment: For the issue of keeping it warm, see https://cooking.stackexchange.com/q/2782/67


Summary by CLRProfiler: Heap Statistics values are 0

Question: I am using CLRProfiler, 64bit for .NET 4.
I am attaching CLRProfiler to a running iis worker-process running a single website.
All values in the Summary-view are always zero.
Only Heap Dumps has a value of 1 and I can see the Heap Graph.
Only if I attach to an exe using 'Profile Application' will I get any values in the Summary-view.
Does anybody have an idea why the Summary-view has no values?
Answer: I was trying to profile a windows service recently and was running into the same issue.
I had neglected to check of the Allocations box prior to starting up my service.  After doing that, I started seeing a lot more info regarding allocated bytes and collections.
See also this question.


Installed new battery not start

Question: My Honda CR-V never have been any wrong or issues before. One week of extremely cold weather my battery died and I changed it with new one but no start, no light, no click at all. What shall I do please any body can give suggestion.
Answer: I would check all the terminals and connections - it is possible you disturbed something when you replaced the battery.
The battery terminals need to be clean and tight
Comment: Would you please put your answer (this answer) onto the other question? Same OP, yet this one is "unregistered". I'm closing this question, as most likely the OP cannot do anything with this one. We'll leave the other one open.

Installed new battery not start


A way to reuse JavaScript code inside my MVC framework

Question: I'm developing a web community in CakePHP and started to have doubts about using jQuery to provide useful widgets around the views when needed.
For example, I've wrote a jQuery plugin which searches the data inside specific input text, asks to my database and get the results handled with events.
Basically the plugin is perfect for simple applications but it's basically useless for a community where I use it almost in all the views and every time handling it with different events and methods, making it with huge event declarations and very annoying to be debugged.
This is just the first of a lot of plugins I'll need to use inside the community, because I would like to have a lot of widgets all around user actions in the site without refreshing the page for small changes.
After some search I thought to solve my problem by implementing a JavaScript MVC based framework inside my web application.
After a read of this article I thought Ember.js would be a nice solution but it seems to be a JavaScript full Application which should be used entirely all over the website than a JavaScript library built to support my CakePHP app (also an MVC framework)
Also does exists some specific framework useful to build reusable widgets?
Comment: I'm confused - I use jQuery on almost every CakePHP project I've ever done, and have had no issues.  What exactly is the problem?
Answer: If I had to do something similar, I'd implement the JS lib for use on layout level (instead of specific view). I'd pick 2 cases - one with the simplest scenario and one with a more complex use case. Then note what are the similarities and differences. That at least would give me a baseline for decision if it's worth pursuing further and would expose the extent to which it will have to be complex.


Jailbroken iphone not charging - neither through USB nor through the A/C adapter!

Question: I use the first generation iphone. My warranty is up like two years ago and I have already jailbroken my phone. It was functioning just fine until one day suddenly my laptop stopped detecting my iphone. I reconnected the device to a PC and the same thing happened. I guess its my mistake that I ignored it!. Then one day while I was riding on my bike,to my absolute horror the phone suddenly slipped from my pants pocket and fell on the rough concrete. I ran and checked but except for a few scratches on the back, it looked just fine, it jus got switched off. I switched it back on and it was working just fine. A week went by while I ignored my phone's inability to connect to any PC whatsoever. It was then that the issue started, Now my phone is not charging at all!. Sometimes either through a stroke of luck or a vigorous shake from me, it resumes charging! Help me out Please!. What am I to do to get it back to normal?!
Comment: have you tried a different cable?
Comment: It doubt the external physical cable connector was damage, as it is protected by the phone's chassis. More likely, an internal cable connector has popped loose or worse, been broken. You will likely have to take the phone apart and verify everything inside is working... or keep shaking your phone to get it to charge ;)
Answer: if you still have warranty on it :

I would suggest you restoring the
  iphone to factory settings and taking
  it to the nearest Apple store.

else :

I believe there is a hardware issue
  (loose connection). Since it is a 3G
  iPhone (warranty may have expired
  unless you got AppleCare), it is not
  difficult to open up and see whats
  going on inside.

Hope it helps!
p.s : When you say 'stroke of luck', things get interesting. You may put your iPhone in Restore mode and then see if iTunes is recognizing it (if you at least have any charge, only then will it be possible to try this!).
Comment: Apple store won't even look at it if they know it's jailbroken.
Comment: I have sent my Jailbroken iPhones (2G, 3G, 3GS, 4) to Apple facility many a number of times. The trick is to factory reset every time you send it in. Try it but only if still under warranty. I am a registered Apple developer. This one time I got a free replacement on an out of warranty iPhone. Apple can be pricey but are great when it comes to service.
Answer: Check the cable slot on the iPhone. Is there any pocket lint in there? Try cleaning it out with some compressed air or gently clean it using a toothpick. I had some very strategic lint block just the right pins to cause this issue on my iPhone. Best of luck.