Data security during laptop repair

Question: Recently bought a new laptop with an extended warranty.
Wondering if when a laptop needs to be sent in to the manufacturer for a repair (specifically a hardware repair),
 is it ok to remove the hard drive when sending it in?
 I don't want to risk my data (security) while in transit and out of my hands.
 Nor do I want to delete sensitive files and restore them when my laptop is restored.
 I guess this would make it tougher to troubleshoot issues and repair the laptop. I don't know what else I could do.
Comment: why not encrypting your drive and sent for repair?
Answer: Your only choices are to remove the hard drive or to encrypt the data on it.  You'll want to check with the manufacturer and extended warranty people to make sure removing the hard drive will not void any warranties.
Many people wind up fixing computers themselves because of this issue.
Answer: Opening the laptop and removing hardware will void the warranty in most cases. Big PC sellers state this in their terms.
The repair people need to test your system as is, with all the hardware that's included.
Encryption is the best way forward.
See this answer about data protection: https://superuser.com/a/238837/380115
Answer: Yes, it is perfectly acceptable to remove the hard drive before sending it in.  I know this to be true for Dell and HP.  Ask your manufacturer yourself to be sure.  They do not need the hard drive to repair any issues, assuming it is a hardware issue.
Answer: As others mentioned Without physical security, you can't have strong protection. So I don't know of any very strong, robust security measure for your situation
I guess the following could give you some protection

Change BIOS settings to boot only from the harddisk, so you can't boot
  from other devices. Make sure to disable network boot, which is
  usually in the same menu.
Set up a password for changing BIOS settings and for startup, so
  nobody can get past the BIOS loading screen without resetting the
  BIOS.
Set up automatic shut down when closing the lid (you should be able to
  do this in the power saving options). That way, intruders will have to
  go through the BIOS password prompt to get anywhere.
Encrypt the whole disk. That way, you'll have to get to the PC while
  unlocked or to add keyboard sniffing to access anything.

.
Answer: You may wish to leave the laptop intact as you could possibly affect Warranty.
Typically, any Return Merchandise Authorization is likely to include a disclaimer about a risk of your data being lost.  Unless you specifically request that your data be retained and provide login credentials (which as an option might not be available) your laptop will very likely be completely drive-wiped before the problem is dealt with by the executing service employee.
Most return process scenarios are handled 3rd party and includes a specific drive-wipe/cleansing stage which is adhered to strictly.  The default action is to hit your laptop with a drive-wipe utility in the first instance.
Also, because the laptop must be certified as functionally tested before it can be shipped back to you, the end result is that a laptop will returned in a fresh "Out of Box" state.
I would recommend backing up your sensitive data beforehand on the notion that it will be wiped.

Data security during laptop repair


Word for person who always judges their actions positively

Question: What do we call a person who always tries to judge their own actions in a positive way, or convince themselves that what they do is always right?
Comment: We call him Happy.
Comment: The norm? Average? or if this is despite much evidence to the contrary, sociopathic?
Comment: is that person can be called  `sanctimonious` ?
Answer: If I understand your question correctly, I think you're looking for the term self-righteous.  From an on-line dictionary:

self-righteous ▸ adjective: showing that you are too proud of your own moral behavior or beliefs, especially in a way that annoys
  other people

Synonyms include smug, priggish, and sanctimonious.  Sometimes, the idiom holier-than-thou is used.
Answer: Words like egotistic or egotistical ("Believing oneself to be better and more important than others") may apply, as may egocentric ("regarding oneself and one's own opinions or interests as most important or valid") or narcissistic (as used in phrase narcissistic personality disorder).  More generally, terms like realistic or unrealistic may apply, depending on whether subject's opinion is correct or mistaken.  In some cases, one might call the person a Pollyanna ("person who is persistently cheerful and optimistic, even when given cause not to be so") or Panglossian ("having the view that this is the best of all possible worlds").
Regarding positive or negative connotations of these and other words, among the set of near-synonyms aloof, arrogant, blustery, boastful, bombastic, cocky, conceited, egotistical, flaunting, grandiose, haughty, insolent, narcissistic, ostentatious, pompous, pretentious, self-important, supercilious, uppity, vainglorious, vain, big-headed, high-and-mighty, show-offy, snobbish, snotty, snooty, stuck up, nose in the clouds, holier-than-thou, in my estimation all carry some negative baggage, and those with the least-negative senses include arrogant, egotistical, flaunting, and supercilious; and of those four, only egotistical is adequately close to the meaning requested in question.  Note that self-righteous is a rather more negative label than egotistical.  Realistic, if you can apply that label, is positive or neutral, and unrealistic is negative or neutral.
I have said terms arrogant, egotistical, flaunting, and supercilious are less negative than others, partly as a consequence of how similar terms are used in Aristotle's Nicomachean Ethics, as for example the lengthy discussion of pride in Book IV part 3.  However, the slightly-technical usage there is uncommon, so only a weak basis for comparison.
Comment: but ego is `negative` word. isn't it? I need positive one
Comment: *Ego* as a word isn't negative.  See recent edit.
Comment: @diEcho: As you can see, most of us assumed you were looking for a negative word.  Maybe we misread your intent entirely, assuming you were looking for a word describing someone who _deluded_ themselves into thinking they were in the right.  If you are looking for a word that describes someone whose motives are pure and noble, then I'd start with _altruistic_, and consult a thesaurus.
Comment: Self-righteous, smug, vain (vanity), toxic positive( toxic positivity ), over positive (over positivity), overoptimistic, complacent, self-satisfied, overbearing, arrogance, arrogant superiority
Answer: How about complacent. From Oxford Dictionary.
Complacent: showing smug or uncritical satisfaction with oneself or one's achievements: you can't afford to be complacent about security.
Answer: I would rather call such a person a bigot: a prejudiced person who is intolerant to opinions other than his own.
Comment: Bigot has a *very* negative connotation, as it implies racial and even religious prejudice.
Answer: We normally refer to what such a person does as self-justification, and because we normally don't agree with his position, we tend to associate the term with making excuses for wrong behaviour, rather than judging oneself positively.
Nevertheless, I think he can be called a self-justifier - one who excuses or justifies himself.


Black screen on boot after installing AMDGPU

Question: I have just installed Ubuntu 16.04 on my computer.
I have an Hybrid video card, with IntelGraphics and AMD Radeon R7 M265. After some research, I decided to try the AMDGPU driver to use my Radeon instead of the IntelGraphics, but I hadn't realized that my video card is not compatible with this driver.
After the installation, I rebooted the system and now it wont start. All I can see after the bios screen is a black screen with a blinking white underline on the left top. Nothing works except when I press the power button and the ubuntu logo appears on the screen for a few seconds before the computer shuts down.
All I want is a way to uninstall this driver.
Answer: Hold down shift key during boot, select advanced options, then select recovery mode. enter in root password when prompted.
The filesystem is in readonly mode, so do command:
mount -o remount,rw /
Now run the amdgpu-pro-uninstall command, which is in your path and you can use tab command name completion.
reboot
if you have problems interrupting grub with shift key, like i did, try to use an older ps2 connector keyboard. usb keyboards/mice are dicey during boot
Answer: You are stuck at booting may be because, you installed amdgpu on your amd Radeon graphics machine.
You will able to boot if you remove the amdgpu-pro.
Lets do it.

Power off your system.
Power on the system, at the same time press on Shift key.
Select advanced recovery option & enter your password
Then type the command:
mount -o remount, rw /

This will give read write permission.
Run command:
amdgpu-pro-uninstall

This will uninstall amdgpu-pro from your system.
To shutdown system, run command: poweroff & then power on the system.


Air Bubbles slowing down

Question: I am distilling. I had air bubbles every 5 seconds and a week later became every 2 and a half minutes. Do I wait till there is none whatsoever or consider it done. Thanks for the help Kris
Comment: Your question needs clarification. First, are you [distilling](https://en.wikipedia.org/wiki/Distillation) liquor? or are you [brewing](https://en.wikipedia.org/wiki/Brewing) something? if you are brewing / fermenting something, what is it & how much volume?
Comment: Air bubbles where? Airlock? Add more details please.
Answer: The bubbles in the air lock are a nice confidence booster but are not a good measure of completion of fermentation. Measure the specific gravity (with a hydrometer or refractometer) at the start and then take a series of readings (say) after 10 days. If the SG is the same over a few days then the fermentation has slowed to a point where one might consider it "stopped".
A correctly made up mash of glucose and Turbo Yeast is generally finished fermenting in 7 -10 days.
I find that a good "rule of thumb" for room temperature fermentation is that they take between 7 to 10 days to "complete". Leaving the fermentation for 14 days will rarely do any harm but may be a longer time than is actually needed. If in doubt and no hydrometer is available then 10 days should be a good period of time to ensure most of the sugars are used up. If the ambient temperature is below 20C then one might increase fermentation time by a day for every 5C below 20C. Again this is a very general approximation and its always best to check with a hydrometer.
As for distillation - that subject is generally beyond this site's remit. But good luck and - reject the first 50cc as it may contain any methanol produced in the mash.

Air Bubbles slowing down


What is the priceRange parameter for Google Structured Data Reviews?

Question: I am trying to determine what are the acceptable values for the priceRange parameter. On Google I see "$$$" and that's it.
Can someone explain if I should be using $$$ literally or a decimal amount.
Comment: Related: [What is the meaning of the priceRange property in Schema.org?](https://stackoverflow.com/q/40790269/1591669)
Answer: It seems there is no "standard" for this, and probably is born out of the rating system for Restaurants.
It seems the convention is:

$ = Inexpensive, usually $10 and under
$$ = Moderately expensive, usually between $10-$25
$$$ = Expensive, usually between $25-$45
$$$$ = Very Expensive, usually $50 and up

Source

It seems TripAdvisor use the local currency symbol as the indicator:

As a reviewer in Korean, you will fill in according to Won ₩, in Greek it will be according to Euros €. Aussies, on the .com.au version of the website get just $ signs, so rather subtle there. The understanding would be AUD$.
Source

But a user has quite rightly pointed out on the official schema.org Github that priceRange is ambiguous.

The property schema.org/priceRange is ambiguous because it specifies text for a currency range...
Source

TL;DR

Use the price property with a range modeled as a PriceSpecification
http://schema.org/price
Source - Github Issue
Answer: The priceRange property seems pretty meaningless, as Shannon points out.
But Google has (within the last few days, as far as I'm aware) started recommending it for all localBusiness structured data, triggering warnings in the structured data testing tool. So, I expect many businesses to suddenly start expressing their pricing in arbitrary strings of $$$, especially those for whom an explicit price list isn't appropriate, e.g. where prices can only be quoted upon request.
It seems that the issue is creating some confusion on the Google product forum, with new image errors and address warnings have started appearing alongside the priceRange warnings. It's possible that Google has unintentionally started treating all businesses as restaurants and will backtrack, but I'm only speculating.
(The question is about reviews, rather than localBusiness data, so this may not be directly relevant to the OP. It's hopefully of interest to others finding this thread first—as I did—after seeing priceRange warnings in the structured data testing tool. I considered entering this as a comment under Shannon's answer, but didn't have enough reputation points...)
Answer: I believe that because they used a symbol ranging from $ / $$ / $$$, that it means that its a relative and not fixed value system.
So to the general consumer, they would interpret $ meaning cheap, $$ being average and $$$ meaning expensive. I personally could not assume a value as three dollar symbols ($$$) could mean two different amounts between two different types of businesses.
For example: a hotel could say $$$, a burger joint could say $$$ and a car dealership could say $$$. In a relative system, this would work as they could all be expensive. On a fixed value system, it wouldn't work and a business such as the car dealership would have to define the value as $$$$$$ for instance but this would just start to look ridiculous to the average person; I mean if it were a boat/airplane manufacturing business, it could be $$$$$$$$$$$$ excluding currency conversion. Fixed value system feels too complicated for an example of "$$$". I would expect an example like "$100-$300 or $25M-$50M" for that type of system.
I do like Richard Wallis's scale in this thread though (https://github.com/schemaorg/schemaorg/issues/1307):
$ = inexpensive
$$ = moderate
$$$ = expensive
$$$$ = very expensive
$$$$$ = if you have to ask the price, you can't afford it*
* Apparently attributed to J. P. Morgan, although disputed


How dependent is Bitcoin on the clock?

Question: Bitcoin takes into account clock of nodes on the network when propagating transactions tru the mempool and persisting them into the next block. If majority of the network clocks are compromised what kind of issues would occur?
Comment: Soon after I posted this question saw an awesome article "Bitcoin is a digital money powered by energy, mathematics and self-interest but its inventor Satoshi Nakamoto was, above all else, a clockmaker." https://twitter.com/dhruvbansal/status/1261372641555906560?s=20
Answer:
How dependent is Bitcoin on the clock?

A lot less than many other applications.

A timestamp is accepted as valid if it is greater than the median timestamp of previous 11 blocks, and less than the network-adjusted time + 2 hours.

https://en.bitcoin.it/wiki/Block_timestamp
AFAIK this means that a block can have a timestamp that is earlier than that of its parent (a block can appear older than its parent). I vaguely recall that there are some such blocks in the Bitcoin blockchain.
So if computers become unable to keep good time to within 2 hours of the correct time, they will start to be problems, blocks will be rejected and the Bitcoin network might, I suppose, fragment.
Note that time synchronisation protocols such as NTP can synchronise times on computers to less than a few tens of milliseconds across the planet, despite significant latency and jitter. There's no good reason for computers to have time drifting apart by seconds, let alone hours.
Compromising clocks might be exploitable but it seems non-obvious.

How dependent is Bitcoin on the clock?


Are my two female guppys pregnant

Question:
In my ten gallon I have two females and one male both females look like this one and if anyone could tell me about how long till birth that would be great
Answer: The gestation period for a Guppy fish is between 21-30 days, with the average often being 22-26 days.  Warmer fish tanks appear to help pregnant guppies from exceeding their due date:

Gestation may last from 21-30 days, although 22-26 days is average for most guppy pregnancies. A warmer tank - between 72-79 degrees Fahrenheit - is best for gestation and will keep the female from being pregnant too long.

I would also say by the looks of it, that they do look pregnant, though it's a little hard to tell through the blurriness.
Here is a picture for reference:

Are my two female guppys pregnant


Fixing Whirlpool Oven Fans and Doors

Question: I have an older Whirlpool oven that has recently started to make noise when I turn it on. I am pretty sure it has something to do with the oven fan. In addition, the door does not seal too well so if I can fix that at the same time I'd be really happy. Is this the sort of thing that can be fixed by myself or a repair person, or am I looking at a new oven? I'd like to think that most ovens are very serviceable, but I am not sure where to start figuring it out.
Comment: What makes you think it is a fan?  Is it a convection oven?  What is the model number?
Comment: I'm not sure if its a convection oven. It is electric. The model number is RBS245PD86. I believe its the fan because the noise and vibration that is happening seems to be coming from something spinning pretty fast. I wouldn't know what else would be in an oven that might do that.
Answer: I think your reasoning is good - it's pretty easy to pick out a the sound of a fan hitting against something. I recommend RepairClinic.com. They have a great site for appliance parts, and lots of info and schematics for what parts are available and how to replace them. You already have the manufacturer and model number, so you are ready to go.
Hope this helps.

Fixing Whirlpool Oven Fans and Doors


VSCode Debug Add Configuration error Cannot read property 'openConfigFile' of undefined

Question: I created a Salesforce project in VSCode and when I try to debug Apex Classes adding a Debug Configuration I get the following error:
Cannot read property 'openConfigFile' of undefined
I'm using the Mac version of VSCode and the extensions enabled and the "salesforcedx-vscode-apex.java.home" set in settings.json file.
Answer: It looks like a bug in VSCode as if you create the file launch.json manually it works and then you can Add the Apex Replay Debugger Configuration.
Create the file under your project folder with the name launch.json
Set the file with the following configuration:
{
    "version": "0.2.0",
    "configurations": [

    ]
}

Save the file and you will see a button "Add Configuration" where you can add the Configuration you need as "Apex Replay Debugger".
Hope it helps!


Replication members count limitation in MongoDB

Question: Is it possible to configure only one secondary and one primary in MongoDB Replication?
Answer: Yes! Of course!
But in the situation where you lose one of the nodes (primary or secondary), remaining node state will be secondary and you cannot insert/update/delete data.
If you can add (one) arbiter to that replica set, your DB will keep working even you lose one node.
Basically arbiter don't need many resources, smallest VPS node what you can find is enough. (512MB memory, 1 CPU, 10GB diskspace) OR you can even add that arbiter to that application machine what is connecting to that mongoDB.
Comment: Thanks a lot, so practically it is possible but it has limitations/risky. I think it is better to add one more replica set/secondary to avoid risk, what do you say...
Comment: Minimum recommended replica set is Primary and 2x Secondaries. But PSA (Primary, Secondary, Arbiter) setup is almost as good, as long as you keep physical/geographical distance between primary and secondary.  Actually PSA is excellent IF all those nodes are at the different data centers. Because on that setup you can loose one (whole) data center and system still works.
Comment: Agree with the PSA approach as the simplest and least resource intensive approach to reducing risk with your replicaset. MongoDB are trying to persuade clients to avoid using Arbiters now though. They won't go away anytime soon, but not recommended. PSS is the minimum recommendation. This guidance was from both a consultant on site and their support team.


Protecting capacitor from high voltage impulse spikes

Question: The purpose of the circuit below is to produce an extremely high voltage impulse over the inductor so that I can place a spark gap in parallel to it and create a very large spark. According to simulation this should work as designed, but I am concerned about protecting the capacitor. The highest voltage rated cap I could find was 30k, but the simulation predicts spikes of -220 kV. I tried placing a diode in parallel to the inductor, but that drastically reduces the voltage spikes. The source controlling the switch is just a simple pulse function switching every 1.2 seconds.
Comment: You don't need a capacitor, just use the back emf. You will need to take care that the relay (or whatever else you have) can take the voltage. The contacts don't just jump to the open position, they take the whole way from contact to open, which means there will be an air gap that will have a finite amount of resistance, and that resistance is variable.
Comment: You could put capacitors in series, with [balancing resistors](https://electronics.stackexchange.com/q/266085/36731) to share the voltage across them.
Comment: You won't get 220kV. To accurately simulate this you need to ensure the parasitic capacitance of the components, especially the inductor are included. The voltage in any practical circuit will be much, much less. It will also be limited by breakdown in the switch.
Comment: If using the cap to charge the inductor (with voltage) to make a spark, instead think in terms of charging the inductor (with current), then interrupting that current. For *that* is what creates the spark (the near-instantaneous collapse of the inductor's magnetic field.)
Comment: The simplest solution is a dry contact relay switch to an energized L with low Parasitic C and rapid velocity to delay  ionization breakdown at 3kV/mm.  ESR and DCR with switch and wiring R's will limit current. But a spark plug  between two step up transformers will create the Tesla corona
Comment: The simulation is assuming that you are running superconducting wires and components that are ideal. Put in parasicitc values for all components and traces (including the voltage supply, an ideal supply can source infinite amounts of current a real supply has series resistance.). The switch also has resistance. Typical pcb traces have 10's mΩ to 100's mΩ. Capacitors also have 10's mΩ and nH for their ESL
Answer: To answer your question: This is not possible, the circuit won't work in reality. As the commenters have already pointed out, there is no switching device (electronic or mechanical) that can handle such high voltages and dV/dt.
To solve your problem: You should instead try to create a transformer-based circuit. A flyback transformer is very well suited for the task of generating long sparks (I've done this a lot as a child).
Your flyback transformer should have a large turns ratio (i.e. 1:50), a ferrite or iron core and an air gap to increase the maximum energy that can be stored in the core. Then you can build a circuit that charges the transformer by applying a voltage to its primary winding. You can do this with an N-channel MOSFET switching to ground. While the transformer is charging, you have to measure the current through it with a shunt resistor. Once the current reaches a certain value (i.e. the saturation current of the transformer's primary), you switch off the transistor. Now the transformer momentarily generates a very high voltage at its secondary winding (which will create a spark). There will also be a voltage spike at the input (but a much smaller one), which is why you should choose a MOSFET that can handle high voltages (i.e. a 600V MOSFET).
Measuring the primary current and switching off the MOSFET has to be done electronically since this has to happen within a few microseconds. You might be able to use a simple NE555 timer for this task. The MOSFET also has to be switched off as fast as possible in order to create the largest possible output voltage.
You also have to be very careful when winding your transformer and use LOTS of insulation, otherwise the spark will form within the transformer and destroy it. (I do have a lot of experience with destroying transformers this way, unfortunately...)


Stern Gerlach Experiment

Question: Since l=0 for a valence electron in 5s state of silver, L=0 and therefore magnetic dipole moment is also 0 which means that the beam should not have deflected at all. So, we introduced the property of an electron called spin which explains the deflection. However, my problem is How the introduction of spin explains the splitting of beam into two parts ?
Comment: How can we conclude that the electron has spin of 1/2 from the observation of deflection or how pauli introduced Spin from the observation of this experiment ?
Answer: As you stated in your question, the effect of an external magnetic field on an atom depends on the magnetic dipole moment of this atom. Before the introduction of spin, the only contributor to the magnetic dipole moment was the orbital dipole magnetic moment:
$$
\vec{M}=\vec{M_L}=-\frac{e}{2m_e}\cdot\vec{L}$$
which does not explain the S-G experiment since its eigenvalue can only be zero when L=0.
However, with the introduction of spin we now have another contributor: the spin magnetic moment:
$$
\vec{M}=\vec{M_L}+\vec{M_S}=-\mu_B\hbar^{-1}(\vec{L}+g_e\vec{S})
$$
Even if L=0, the eigenvalue(s) of $\vec{M}$ will still depend on the value of S and there can thus be several of them, which means your observation (effect of external field B) will also have several possible results which eventually means several deflection angles and splitting of your beam

Stern Gerlach Experiment


How to get more full speed USB 2.0 ports on a modern laptop?

Question: Modern laptops just have a few USB ports and to extend thoose you are supposed to use a USB hub. My issue is that I need to connect 4 highspeed USB 2.0 cameras to my laptop and while still keeping two USB port free (mouse + usb-stick). On a normal USB 3.0/2.0 hub all connected USB 2.0 devices share the same ~40mb/s bandwidth limit, but each camera needs the full 40mb/s on it's own.
So is there any way to get more full speed USB 2.0 ports on a modern laptop?
Comment: If you already own the cameras it may be too late.  Use Bluetooth or WiFi cameras rather than USB.  You could convert a USB camera to Bluetooth, but it would be more expensive than buying a Bluetooth camera.
Comment: @fixer1234 perhaps wired ethernet cameras would be the best solution here. More-so if OP has PoE available.
Answer: Since you have listed the Thunderbolt tag, it is worth looking into a Thunderbolt dock with USB ports. In the case of Thunderbolt 1 or 2, I believe there are not USB ports routed with the connector, so any external USB ports would be on an external controller. In the case of Thunderbolt 3, since those ports are often paired with USB-C, the dock may be cheating for the USB and just be a USB multiplexer.
If you think a Thunderbolt dock is the way to go, I would suggest getting one with a good return policy and measuring it to make sure it fits your needs.
However, there is always a more exciting option.
Depending on the age of the laptop and what ports you have available, you can consider an M2. to USB 3.0 adapter or a Mini-PCIe to USB 3.0 adapter. Both of these would vastly compromise the portability of any laptop connected to them, but would be a simple and cheap answer to "how do I get more USB ports"
Mini-PCIe does not provide any USB 3 ports, so that adapter almost certainly has its own controller. In the case of M.2, it is almost certainly just routing out the USB ports in the connector, which (hopefully) go straight to the CPU, so should be full-bandwidth.
I cannot post any more links, so some naked suggestions follow
The Mini-PCIe does provide one USB 2.0 port which (hopefully) is connected straight to the CPU. This is cheaper than the USB 3.0 option, and is less likely to be a driver disaster.
Another option in a similar vein is to get a PCIe USB 2.0 card and a M.2 or Mini-PCIe to Desktop-Form-Factor PCIe. The laptop is now totally non-portable, but has a great many USB ports.
Finally, I don't know your usecase, but it may work to get two cheap and junky laptops and connect two cameras to each.
Comment: Also, if you are not married to the laptop, the Intel NUC can be made to have six USB ports with a semi-custom case: https://www.amazon.com/Intel-NUC-Additional-Dual-Ports/dp/B01BJ0898Y
I have never used this thing, I only know that it exists.
Answer: It is very likely that your laptop has only ONE USB host controller. The aggregate bandwidth is determined by controller architecture. So, one controller - 40MBps.
To accommodate 4 USB 2.0 HS cameras, you would need FOUR controllers in your system.
If it is a less-modern laptop (that has one separate EHCI and one xHCI USB 3.0), then connecting one camera to USB 3.0 port, and another to a USB 2.0 will give you the bandwidth for two cameras, but you need to check how your exposed ports are routed, to which controller. If there is only one xHCI, then no luck. And I doubt that your laptop has more than one M.2 slot with direct PCI.
ADDITION: Here are my quick results.

On old and not so old Intel machines, EHCI (USB 2.0) controllers (at least on relatively new C20x chipset, 2011, and on all older ICHx chipsets) split the available ~42 MBps bandwidth between all root ports.
Renesas USB 3.0 xHCI add-on PCIe card controller also splits the 42 MBps between ports;
ASMedia USB 3.1 Gen.2 controller on 4X PCIe slot also splits the bandwidth;
Only newest Intel xHCI USB controllers, Braswell family and newer (2015) do provide full USB 2.0 bandwidth on individual ports (verified on three ports, I don't have more).
Any internal or external USB 3.0 hub will split the USB2 bandwidth between ports.

Therefore, I stand corrected regarding the latest Intel eXtensible Host Controllers - they do provide full USB 2.0 (~42 MBps) on each port.
Comment: I was able to test your theory on a lot of machines. Intel machines no matter how old, which chipset or which formfactor they got, was able to provide full 40MBps on all available ports. The AM4 plattform on the other hand is sharing the 40MBps USB 2.0 bandwidth over ALL ports including USB 3.0/3.1 ports.
Comment: Your updated results seem to make sense. Do you have any Informations regarding the USB controller used on for the AM4 X470 and B350 chipsets?
Answer: Consider using a USB 3.0 hub.
Alternatively, there are hubs designed to be USB 3.0 to multiple 2.0s and (some of) they should work, too.
A hub is basically a chip connected with ports and a plug. The chip runs for the hub and manages data between devices and host. So if you use a host with USB 3.0, you'd be able to divide its speed (bandwidth) into multiple USB 2.0 ports, as long as the hub supports.
Beware with 7-port hubs. I dismantled a few and found there were 2 chips connected together, so 4 ports will be slower than the other 3.
Comment: This answer is incorrect. USB 3.0 hubs do NOT split USB 3 bandwidth into several USB 2.0 ports. You are confusing USB 2.0 concept of Transaction Translator in HS-FS-LS topology. USB 3.0 does not have this luxury. See this answer, https://superuser.com/a/1159659/620011
Comment: "On a normal USB 3.0/2.0 hub all connected USB 2.0 devices share the same ~40mb/s bandwidth limit, but each camera needs the full 40mb/s on it's own." See https://superuser.com/questions/1159167/usb-2-0-high-speed-on-all-ports


Tree vs Graphs in search

Question: Could anyone give a clear and concise explanation for when you use graphs vs when to use trees for data structures?
Answer: Trees are Graphs.
They are specifically directed, acyclic graphs where all child nodes only have one parent. If you need more than one parent then you use a DAG. If you need cycles or the graph needs to be undirected you'd use some kind of graph implementation. Note that the time and space complexity increases dramatically once you move into full graphs.
Comment: "where all child nodes have one parent": In order to speak of a child-parent relation you need a directed tree. In an undirected tree you can pick an arbitrary leaf as root (and define the parent-child relation accordingly). In fact, a DAG is a directed acyclic graph, and a tree is a DAG with no parallel paths. So I think you should define trees as "directed acyclic graphs where all child nodes have only one parent" or "directed acyclic graphs with a distinct root node such that there exists exactly one path from the root node to any other node".
Comment: typed undirected when I meant directed.

Tree vs Graphs in search


How to setup Phonegap Build with PushPlugin, Apigee on Android

Question: I am trying to setup a Phonegap (v3.0.0) project with push notifications through Apigee and build the project using Phonegap Build using the command line interface.
Here is what I have so far:

I installed Phonegap on my Windows following these directions.
http://phonegap.com/install/
I used the Phonegap command interface to create a project.
http://docs.phonegap.com/en/3.0.0/guide_cli_index.md.html#The%20Command-line%20Interface
I downloaded the Apigee Phonegap PushPlugin from Github and added the plugin to my project using the command line interface.
https://github.com/apigee/appservices-phonegap-push-plugin
I followed the Apigee push notifications tutorial to setup Apigee and Google notification service.
http://apigee.com/docs/usergrid/content/tutorial-push-notifications
This is where I get lost... I am trying to follow the Apigee phonegap android sample app but the tutorial file structure and the file structure of the current phonegap project is completely different.
https://github.com/apigee/appservices-phonegap-android-push-example

Which files do I need to use from the Apigee demo app and where do I include them in my current phonegap project? I tried to follow the directions to configure the Apigee PushPlugin but during build Phonegap tells me the plugin is invalid and not supported.
Can someone help and offer me step by step instructions which files I should configure, copy and where in order to build the project using Phonegap Build and so the device sender id that is generated successfully gets sent to Apigee?
Thank you
PG
Answer: The current Push notification plugin was made to be used with PhoneGap 2.6, so you will need the older version of PhoneGap for this to work. Once you are running 2.6, you should be able to get it running with the instructions in the readme.
Comment: Hi, thank you for the answer. Well I attempted to install v2.6.0 by downloading the zip from Phonegap but I am unable to install it using the command line interface. Is there a specific way to install the older version?


Funny or entertaining material for professor

Question: I'm having "Lebesgue's Integral and Fourier Series" as subject this year in college, and my professor not only marks us by our work, but also by our attitude, or even our capability to negotiate our own grade.
The thing is I'm doing pretty well, but I noticed last time there was something that helped improve the grade a little bit: I found over the internet an article by Desmond MacHale about 13 (general) questions you can ask in a mathematical conference which you didn't understand at all. It made him laugh, like a lot. He liked it so much that he even showed it to the rest of professors, and he read it out loud in his classes.
There are a couple of works left to do this course, and I believe he is expecting more material of this type. Can anyone recommend me some of it? It hasn't got to be funny, it could be sometwhat entertaining in an interesting or curious way.
Thanks in advance.
Comment: I can't help, but do you have a link to that article?
Comment: I'm curious about the 13 questions too, but while searching for it I came across this: https://www.sixthform.info/maths/?p=66
Comment: I read the article here: https://www.jstor.org/stable/2975693?seq=1#metadata_info_tab_contents
Answer: Actually, I lied, I can help: all of this is blatantly stolen from Appendix E of Samir Siksek's excellent Introduction to Abstract Algebra notes (which is inexplicably missing from the version that I can find online - this is a new thing, it was definitely there last time I went looking). This appendix is entitled The Forgotten Joys of Analytic Irresponsibility and opens with a disclaimer ending with

Needless to say the material in this appendix is merely for the mortification of fellow Warwick
  academics. Students must stop reading at once or they'll do irreparable
  damage to their souls.

There follow two wonderful things which I shall rather generously call proofs, of which the second (apparently taken from MathOverflow, though I've never found it there) reads:
Let $\int = \int_0^x$. We wish to solve the integral equation $$f(x) - \int_0^x f = 1.$$ Factoring out the $f$, we have $$\left(1 -\int\right)f = 1, $$ and hence \begin{align*}f &= \left(1 - \int\right)^{-1}1\\&= \left(1 + \int + \int \int + \int \int \int + \cdots\right)1\\ &= 1 + \int_0^x1+\int_0^x\int_0^x1+\int_0^x\int_0^x\int_0^x1+\cdots\\&= 1 + x + \frac{x^2}{2!} + \frac{x^2}{3!}+\cdots\\&=e^x.\end{align*}
Comment: This feels like a fancy analog to anomalous cancellation. Except, It seems like more than just a coincidence. I wonder if there is any meaningful explanation for why this "works out"?
Comment: Sure, $\int$ as defined is the Volterra operator, whose boundedness yields the applicability of the Neumann series expansion to $(I - \int)^{-1}$. It is just this expansion that is used here.


SQL Server: importing from Excel, only want the new entries

Question: The task is to have SQL Server read an Excel spreadsheet, and import only the new entries into a table. The entity is called Provider.
Consider an Excel spreadsheet like this:

Its target table is like this:

The task is to:

using 2008 Express toolset
import into an existing table in SQL Sever 2000
existing data in the table! Identity with increment is PK. This is used as FK in another table, with references made.
import only the new rows from the spreadsheet!
ignore rows who don't exist in spreadsheet

Question:
How can I use the SQL 2008 toolset (Import and Export wizard likely) to achieve this goal? I suspect I'll need to "Write a query to specify the data to transfer".
Problem being is that I cannot find the query as the tool would be generating to make fine adjustments.
Answer: What I'd probably do is bulk load the excel data into a separate staging table within the database and then run an INSERT on the main table to copy over the records that don't exist.
e.g.
<code>INSERT MyRealTable (ID, FirstName, LastName,.....)
SELECT ID, FirstName, LastName,.....
FROM StagingTable s
    LEFT JOIN MyRealTable r ON s.ID = r.ID
WHERE r.ID IS NULL
</code>
Then drop the staging table when you're done.
Comment: and if you're on SQL Server 2008, by all means, use the new MERGE command!
Answer: You can run some updates on that stage table before you load it, to clean it up, if you need to, as well.  UPDATE SET NAME = RTROM(LTRIM(Name))
FROM YOUR.STAGE.TABlE for example


How do I prevent players from riding a donkey, but still be able to access its inventory?

Question: I am trying to make a data pack in Minecraft 1.16 where you can equip gear without taking up space in the player's inventory.  I have it set up that when a player holds a specific item, a donkey is teleported in front of them.  So then the player can access its inventory, but I don't want the players riding the donkey.  How do I make the donkey unrideable, but players can still access its inventory.  I tried putting an armor stand on the donkey that works to prevent me from riding the donkey, but I can't access the donkey's inventory.  I can't use a chest in a minecart because I can't make that invisible without removing the minecart texture (which I don't want to do).  If mules work but donkeys don't that's fine.
Any Ideas?
Answer: While this doesn't directly answer the question, it is possible to use a command block to forcibly dismount the player if they do ride the donkey. This isn't perfect, because it still shows the "Press shift to dismount" screen, but it does prevent the player from riding. To do this, run
/execute as @a[nbt={RootVehicle:{Entity:{id:"minecraft:donkey"}}}] at @s run tp @s ~ ~ ~

in a repeating command block. (A player automatically stops riding when they are teleported)
The above command prevents the player from riding all donkeys. If you want to only effect some donkeys, then best way to do this is using a tag: summon the donkey you want to be unridable with Tags:["dummy"] and change the above command to:
/execute as @a[nbt={RootVehicle:{Entity:{id:"minecraft:donkey",Tags:["dummy"]}}}] at @s run tp @s ~ ~ ~

Comment: The player could abuse that and keep spam riding the donkey to virtually fly.  Other than that, it would work.


Can anyone identify this uniform, approximate year, and aircraft?

Question: It's U.S. from the interwar years, but I don't know much more than that.
Comment: Are you sure on this being [interwar period](https://en.wikipedia.org/wiki/Interwar_period) ? It seems the [Aviators Badge](https://en.wikipedia.org/wiki/Aircrew_Badge) would indicate WW2 or later...
Comment: The collar insignia appears to be a [Prop and Wings](https://en.wikipedia.org/wiki/Prop_and_Wings), which doesn't help much, giving a probable range of  1920-1947.
Comment: He's a captain, and the boxy insignia could be WW1 or WW2. That looks like a WWII ***Aircrew*** Badge (I think that's what @justCal meant). That is probably a WW2 observation aircraft. I can't be sure which one, it's hard to find pictures of the engine cowling straight on like that. We can rule out radial engines.
Comment: Yep, knew the rank, and the badge was used by both the Army Air Corps and the Army Air Service before. What I'm not certain of that it *is* the Army. Were there any services similar to the ANG at that time?
Comment: And @justCal, no. I'm not 100% certain that it's interwar, but given his age (It's my grandfather) I *think* it is. He was born in 1903, and was a member of the OX-5 club -- He was flying well before WWII.
Comment: @Schwern Aircrew, yes (what I linked to not what I wrote). I agree the plane is tough to find, the Pipers, Cessnas and Stinsons dont seem to match,  but they all list lots of variants in the L series planes.
Answer: Having been a USAF Senior Historian Technician (792Xs/3HO71) from '84-'96, I've researched many similar queries over the years, and these were always some of my favorites to puzzle over.  Even just getting a few clues right can help provide fun family history detail.
The uniform dates to the later U.S. Army Air Corps/U.S. Army Air Forces days, rather than the earlier (W.W. I-era) U.S. Army Air Service.  What we see the Captain wearing is a 'combination' service dress uniform of the late 1930s to early 1940s, a mix of two different shades of complimentary uniforms issued in that era that later came to be known as 'pinks & greens' (dark olive and khaki tan, the latter of which was dyed of a certain tint that appeared slightly pinkish under certain light).  Officers had the latitude to wear various mixes of the two uniforms (and accessories) at the time, while junior enlisted folks had a more standardized drab wool uniform.  The "tucked" tie also indicates this is closer to the 1940s than the 1930s.
He sports aviator's collar brass which can encompass a variety of flying jobs, including association with Air Cadets.  In his context as a captain he might have been a trainer of young aviation crewmen (possibly of the observer corps), and at his rank he could possibly even have held a lower-level command position of some kind.  Typically one has to be a Major or above to be a squadron commander.
He does not wear the standard pilot's wings over his left breast pocket; these wings instead indicate he was aircrew personnel.  For a pilot's insignia, there would have been a shield between the wings, and often initials U.S. inside it in some fashion (there were many variations).  Instead of a shield, here we see a roundel-shaped emblem between these wings, most likely with the National Seal (the Eagle, Arrows and Olive Branch), which indicates air crew personnel (other than command pilots).
You mentioned the OX-5 club...  The OX-5 was the powerplant used for the old Curtiss JN-4 Jenny (NOT the aircraft behind him), a primary trainer for pilots involved in World War I.  His age indicates he would have served just before or during World War II (or more than likely, both to have the rank he earned).  Chances are he flew Jennies for fun (plenty were used as barnstormers and trainers for civilian pilots) long before his association with whatever high-wing monoplane it is he's leaning against.  Judging by the height and shape of the cowling and intake slats behind him, it does NOT appear to be a typical "L-Bird" (Liaison aircraft) of the time (Stinson, Aeronca, Taylorcraft or Piper).
Here's my best guess as to the type of wings he is wearing.
Answer: This is a Civil Air Patrol uniform. They are officially known as the Air Force Auxiliary, and are somewhat jokingly referred to as "America's best kept secret". Unfortunately I don't recognise the wings as any we used during WW2.
The aircraft looks like an older version of a Piper Cub.


Are there any libraries for generating flash swf files or converting svg to swf

Question: I was wondering if anyone knows of any libraries for programatically creating flash swf files.
Or for creating swf from svg.
Comment: I ended up using SpriteGraphics2D to do what i needed, you can read about it here.
http://stackoverflow.com/questions/267001/save-java2d-to-swf-flash/269714#269714
Answer: This sounds like a perfect job for swfmill I think you'll find it will allow you to do both, convert SVG to SWF and to create SWF files from code.
Answer: Ming, which is written in C can generate SWF content.  There are bindings for Ming in Perl via the SWF module and I believe it can be used with PHP as well.  As far as SVG to SWF conversion, it looks like there's a Python program that can do that, but it sounds as though it's still a bit rough around the edges.
Answer: You should check out SwfDotNet . It's done in .NET.
Here's an example check this out:
How to transform JPEG to SWF on the fly
Answer: It seems swfmill is not as good as the standard mxmlc to convert and embed SVG files.
I tested it on some simple files and it lost all color and font information.
For me, the question is still relevant, because mxmlc also loses some attributes of my SVG files, mainly gradients...
Answer: You can use Aspose.Flash to create SWF files from scratch or from an SVG file. You can get complete help from the Programmer's Guide and Demos. You can also ask question in our forums for any technical issues or concerns.
I'm a member of the Aspose.Flash team.
Answer: It's an early days project, so there may be some fiddling, but Swiffotron can load, modify, generate and combine SWF files.


Uploading an image to a Rails server via an Ember.js app

Question: Like it says on the tin, I'm trying to upload an image with my Ember.js app to a Rails backend that's using Paperclip to manage file uploads. I had a look around and couldn't see any simple way to do this, does anyone know of a good solution here?
Answer: I faced similar recently, and it turns out that there are lots of complications with file uploading - does the device support it, do you want to be able to style the input that triggers the upload, etc.
We opted for Jquery File Upload: https://github.com/blueimp/jQuery-File-Upload
The approach I took was to upload directly to S3 from the browser, and then set the token that S3 returns as a property on a model, then save that to the server. Then on the server, you set off a background job to pull in that file from S3 and put it where it should be.
Comment: why didn't you just leave it in S3?
Comment: Because it needed processing - resizing etc.
Answer: I wrote a fairly simple ember.js file upload example a few months back that shows how you can write a custom view + a custom adapter that allows you to post a multipart form back to the server. The example I did is built for python / django but the concepts should apply
https://github.com/toranb/ember-file-upload
I recently upgraded this to RC1 (like 5 minutes ago) and it appears to still work :D
Comment: Is a custom adapter neccessary for file upload?
Comment: not 100% but you do need some code (model or adapter) to serialize the form data and post it
Answer: There is now an Ember Uploader plugin for Ember. I'm just in the process of integrating it right now.
I have a couple kinks I'm ironing out, but it seems pretty legit. Probably less configuration than using the jquery file upload.


List all DNS records for host

Question: We have an issue with DNS in our environment where the DNS record for a computer will not get updated when it moves to a new subnet. I manage our desktops so I have no access to nor am I involved with our DNS or DHCP servers. I know this a DNS or DHCP problem, however our server team has been unwilling or unable to fix it for several months now and I don't expect to have it fixed soon.  I'm not looking for a solution to this DNS/DHCP problem, I'm looking for a workaround to find the computer's current IP when it does happen.
Take a look at the following CMD output:
C:\>nslookup pwd-d5767
Server:  dnsserver.mycity.nw.us
Address:  172.16.1.16

Name:    pwd-d5767.ci.mycity.nw.us
Address:  172.18.74.147

C:\>nslookup 172.18.45.174
Server:  dnsserver.mycity.nw.us
Address:  172.16.1.16

Name:    pwd-d5767.ci.mycity.nw.us
Address:  172.18.45.174

The computer PWD-D5767 was in use on one subnet and got the IP address 172.18.74.147.  It was then moved to another subnet and got 172.18.45.174, which is it's current ip address. As you can see from the forward lookup, I get the old address when I lookup the hostname. As I did in this case, I normally have to call the user and have them do an ipconfig and tell me their current IP address. Calling the user and walking them through doing an ipconfig is a pain.  However, it appears our DNS server knows the computers new ip address based on the result when I do the reverse lookup. I want to avoid calling users and having them read me their ip address.  Is there an nslookup or some other command that would give me all the IP addresses the DNS server has for pwd-d5767?
Comment: SO basically you want to query all reverse dns lookup zones for a particular hostname. What type of DNS server? Windows? Linux?
Comment: is this related to DNS-caching in any way? Check [this article](https://support.rackspace.com/how-to/nslookup-checking-dns-records-on-windows/) it has some helpful info
Answer: Well since your DNS server is wrong why not talk directly to the computer like you are doing manually with the phone call
open Powershell:
Get-WmiObject win32_networkadapterconfiguration -ComputerName pwd-d5767

Comment: actually yeah - how is anything working, must be a lot of stuff going into black holes
Comment: That is still going to use the wrong/old IP as it will do a DNS query for pwd-d5767
Answer: From what I can tell is that your PTR records are updating but not your A records in DNS. If that is the case, you can search by subnet with nslookup.

ls -t PTR [subnet].18.172.in-addr.arpa

List all DNS records for host


Is that the correct way to use TMS in GeoServer

Question: In GeoServer, I'm not found TMS Demo, so I read the GeoWebCache doc about TMS, and following the TMS protocol as the doc mentioned, try to construct the url: http://localhost:8080/geoserver/gwc/service/tms/1.0.0/topp%3Astates@EPSG%3A900913@png/5/5/20.png and request my local GeoServer, and I get the picture successfully from the server.
So my question is: the url above is the correct way for use TMS in GeoServer? In other words, the clients(such as leaflet) use that url format to request GeoServer is the correct way?

The "topp:states" layer(in url above) is a predefined layer in GeoServer, and I manually seed/truncate the layer using GridSet EPSG:900913.

Edited:
@Ian Turton Is the link you mentioned?
Answer: GeoServer provides a GetCapabilities link on the server home page that provides all the information a client requires to access the TMS service. This is both machine and human readable. There is no need to provide a demo to a well known protocol.
Comment: Is the link in above picture as you mentioned?
Comment: that's the one just click and read it


Which artificial intelligence is haram and which is not?

Question: Today's Artificial intelligence are capable of doing what human can do (playing chess , chatbot) . But to which limit an artificial intelligence is considered haram ? For example , creating a sentience artificial general intelligence which is capable of being a living thing , is it considered haram ? how about artificial intelligence with eye(camera) and ear(microphone) but only can do specific task such as playing chess , chatbot , ect ?
Answer: Afaik we have not yet reached the stage where science & technology can create a sentient creature in true sense of the word.
The examples you gave of chess playing or a chatting application are nothing more than a few hundred thousand of lines of either POP or OOPs programming. They do not replicate the human feature of self awareness nor can they take decision that goes against their core SDK.
The same can be extended to an eye (camera) or an ear(mic) both of which are a subset of a larger software designed to perform designated tasks.
We have had robots in the manufacturing industries for almost a century now and yet we are far from creating one that can replace complete human team to research and develop a product independently.
Either you confuse AI with 'creating a life form' or you have misconstrue your question. Nonetheless, I pray you find an answer that suffices your question in the light of Islam.
Comment: okay i get it so ai that only can do specific task is no more than just an algorithm that perform designated task , but how about artificial general intelligence ?  and how to determine whether an artificial intelligence is considered as haram (in the case of it similarities with living thing) ?
Comment: as far as i know , artificial general intelligence (sentience ai) is also "nothing more than a few hundred thousand of lines of either POP or OOP programming"
Comment: @i'mashamedwithwhatiasked I didn't understand your  first comment.


How level yard after removing planter boxes

Question: planter removed
We have planters in our backyard that we would like to move to the side of the house. How would we level this ourselves without any big machinery?
Answer: You will need a person with a strong back, a sharp square spade, and a couple of sheets of thick plastic or tarp. Choose a dull day, it will be easier to work and exposed roots will dry out less quickly. Water the ground the previous evening and allow to drain down overnight.

begin by imagining each of those squares of turf sectioned into about nine (3 by 3), or 16 if it is easier, subsections and give the squares a haircut with a string trimmer or shears to about two inches grass height
use the sharp spade to vertically slice down to a depth of about one inch or a little more to mark out the subsections; if you have a half moon spade this will be much easier
starting from a convenient corner slice horizontally so that you remove one of the nine squares to end up with a piece of turf one inch thick; set this piece of sod aside on one of the plastic sheets
remove the remaining sod pieces and pile them up conveniently on top of or to the side of the previous one removed
at this stage you have two squares of bare earth standing about nine inches proud of the rest of the grass
now remove this extra soil leaving the new level about one inch below the lawn surface; the soil can be removed to a wheelbarrow and carted to a new location or put on the other tarp temporarily
with all the extra soil removed, dig over those bare patches to loosen up the soil and check for large debris; the result will be that the soil will perhaps stand a little proud of the rest of the grass but will settle back to an inch below after a few good rains
replace the sod pieces in the squares. Set the pieces out evenly; this may leave gaps between the sod pieces - they can be filled in with some of the extra soil previously removed. Perennial grasses will spread sideways to fill these gaps.

Keeping this area watered will allow it to settle back so that the result is at the same level as the rest of the grass. Mow as usual once settling has taken place and the grass should re-establish itself and merge with the rest of the lawn quite easily.


Pulse shaping filter for FSK

Question: After a BPSK modulation we have the upsampling and the pulse shaping filter. But for a FSK, do we have upsampling and pulse shaping filter, or just the pulse shaping filter?
Comment: In a modern implementation you would create the FSK signal in discrete time at a low intermediate frequency, then upconvert to RF in the analog front end.
Answer: Most likely yes. FSK is already generated using many samples per symbol. Look at Matlab fskmod function.
Answer: In BPSK, you need one pulse shaping function. On the other hand, M-FSK needs M pulse shaping functions corresponding to each symbol. Let $g(t)$ is the pulse shaping function for BPSK. In M-FSK, you can say that $g_m(t)=g(t)cos(2\pi f_H m t)$. Here,$g_m(t)$ is the pulse shaping function corresponding to the m-th FSK symbol and $f_H$ is the frequency hop between the two adjacent symbols in frequency.
Answer: Pulse shaping with FSK is routinely done. We see this most often in pulse shaped variants of Minimum-Shift Keying (MSK) which is FSK with the frequency symbols spaced at minimum separation while maintaining orthogonality ($\Delta f=1/(2T)$, where $T$ is a symbol period and $\Delta F$ is the frequency separation of the tones used).
Straight MSK has no pulse shaping, and for this the frequency versus time represents rectangular pulses as the frequency transitions from one to the other. Gaussian-MSK (GMSK)  is a very popular waveform and good example of pulse shaping with FSK. Here the frequencies are instead formed as Gaussian shaped pulses. The symbols are first represented as rectangular pulses which are then passed through a FIR filter with Gaussian shaped coefficients with a time duration in the filter of one symbol period (or multiple periods for partial response signaling where intentional ISI is introduced to improve spectral efficiency as further described below).   The output of the filter represents frequency versus time and those samples can be used as the Frequency Control Word to an Numerically Controlled Oscillator to complete a GMSK modulator.
Further such an implementation is very convenient for partial-response signaling with GMSK (as is often done) where the spacing between symbols is less than a symbol period thus increasing spectral efficiency (more data in the same bandwidth) at the expense of receiver complexity due to the intentional inter-symbol interference created; since the Gaussian filter and therefore the impulse response of each symbol is one symbol long.  Simply space the unit samples representing data at the input to the Gaussian Filter closer together and the convolution property of the filter will properly combine the partial response signals.
Of related interest, very conveniently, such a Gaussian filter can be implemented with no multipliers, as can the NCO, resulting in a very efficient modulator solution when multiplier resources are a premium. For more details on this see the following two posts:
Gaussian FIR filter with no multipliers?
Simplest All Digital GMSK Modulator

Pulse shaping filter for FSK


What is called when two pictures are combined

Question: Like say, for instance, I saw a picture of the front of a older and newer Toyota Supra like it was transforming and it was cut in half.
Comment: I think any image that is created from more than one photographic exposure can be called a [_montage_](https://en.wikipedia.org/wiki/Photomontage). But, if you are thinking of a specific technique or a specific effect, then there may be a better name for it.
Comment: Can you at least provide a link to an example? There are several different ways that multiple images may be combined to create a single image. Depending on how this is done, there are several different terms for it. Layering, focus stacking, stacking to reduce noise in dim astro photos, exposure fusion, montages, "multiple exposure" effects, etc. are just some of the many different ways multiple image sources can be used to create a single image.
Answer: A combination of multiple photographs is a "photomontage". More generally, the process of combining visual elements from multiple sources to form a single image is called "compositing", and such an image may be called a "composite image" or simply a "composite".
Answer: A combination of multiple images is known as a "Photocollage".


Some vertices move and are not smooth in pose mode and weight paint

Question: I don't know why the vertices has changed. Although when I went out to look at the original edit mode. There was nothing wrong. This happens only in the right hand.
Previously, I had weighted in the hip section. But when I check the weight of the hips, it has no effect on the hand. (pic 2)  Please guide me how I can solve this problem. Thank you.
Answer: Then you set weight for a vertex, let say 100%, for 1 bone it doesn't mean that this vertex will move 100% with this bone. Not at all. One vertex may be in several groups at the same time, and the sum of all these weights may be more than 1. So the influence that bone has at the specific point equals its weight divided by the sum of all weights.
If you select a point, you may see something like this:

From this, you may find that other bones affects on this point.
And of-course, you may find useful to use auto-normalize option:

Which keeps the sum of weights always equal to 1.
Comment: I can solve that problem. And to fix this problem in the future ,I have to right symbol auto normalize before start weight paint. Thank you very much.


How does Google Docs differ essentially from other services like Dropbox

Question: I have a Google account so I would see it as straight forward to use only Google Docs for storage and everything. I have read that Dropbox does not permit uploading of folders which is time consuming. Is Dropbox then redundant with Google Docs? Other programs similar to Dropbox exist as well and I am trying to see what the difference is between categories or if there even is one.
Answer: The great thing about Dropbox is that anything in the Dropbox folder is always up to date on your computer, even if you have multiple computers, or are working with multiple people. They do require that everything be in one folder (on Windows 7 it's C:\Users\me\Dropbox\, on OSX its /Users/me/Dropbox/, etc.) but one thing you can do is just use softlinks on OSX/Linux or Junctions on Windows so you can leave your files where they are and just put the link in the Dropbox folder. There are tutorials and tools that make this easier than it sounds - see http://wiki.dropbox.com/ for some good tips.
Google Docs thinks of things differently - your stuff is always "in the cloud" -, which means there is only one copy, so things don't get out of sync, but it also means that you can't get to it if you don't have an internet connection.
Comment: so drop box does more of a synchronization facility, and Google Docs more of a storage unit? thanks
Comment: This answer is severely out of date; Google Docs since became Google Drive and acquired the features of Dropbox mentioned here; also Dropbox acquired some of the editing capabilities of Google Docs.


How to inspect state of smart-contract whose code I do not have?

Question: Often it is argued that one big advantage of blockchains is that anyone can come along and inspect the state. However I have not found any practical guide for doing this. Block explorers allow us to inspect transactions, but not state variables (as far as I know). So then how can I inspect state variables for any given smart contract already deployed?
Answer: EDIT: The blockchain explorer below is unfortunately dead. So far no blockchain explorer has shown contract state as clearly.

The ether.camp blockchain explorer allows some of this.  Go to https://live.ether.camp and then click on "Smart Contracts."
Developers have to upload their source code to ether.camp, because raw code on the blockchain are just EVM bytecode / assembly.  As time goes on, we would expect such tools to improve and be more prevalent.
For example:
https://live.ether.camp/account/49f053b866c33185fa1151e71fc80d5fe6b08a92

ether.camp already shows the state for any given smart contract, but attaching the source code to the contract significantly improves the user experience.
Comment: Ok well is it even possible to do this for smart contract whose source code we do not have? Furthermore, does there exist tools today where we can do this?
Comment: I added screenshot (when there's source code) and commented that when there's no source code "ether.camp already shows the state for any given smart contract".  I could edit answer to answer "who's code I do not have" first, but that functionality has been around longer and I thought it would be more familiar to people already.
Comment: Website not more reachable.
Answer: Etherscan.io offers some of these features. Look up your contract by its address and view the Contract Tab.
There is a chance the developers published the source code and thereby verified the contract.
If this is not the case you must do with trying the decompiled bytecode or the opcode view.
Comment: State variables? I have not seen this. Functions, yes. Transactions, yes. Not current state. Can you link me to an example of this that you've seen on Etherscan?
Comment: @RyanShea They are accessible only through respective getter functions which granted there are any, can be easily run on etherscan. All the constant state vars can obviously be viewed right away.
Comment: Yes I am aware of what you're referring to but this is not contract state. The tokenURI getter function for ERC721 is an example of what you're talking about. What I'm looking for is the ability to see into global state variables of the contract. For example, if you add addresses one at a time to a list, it'd be nice to see the up-to-date fully constructed list.
Comment: The answer from 2016 has a link to the old EtherCamp explorer which has essentially what I'd want but it is no longer functional.
Answer: Etherscan has this service for sure, You can even debug the smart-contract and run different transactions.
Answer: The OP is asking exactly the right question. Every participant should be able to inspect all of the data all of the time. But, the two suggested sites mentioned above are a compromise on the real solution. A very important aspect of these cryptocurrencies that is being increasingly lost is the idea full decentralization. The true solution here is not web-based tools that centralize the data. The true solution would allow quick, easy access to all the data all the time directly from a locally running node. Not really an answer, just an important point this seems to rise above the level of a comment.


Dating Colloquial Expressions and Slang

Question: I remember hearing "be more chill" meaning, "calm down" in the nineties but it was not in common use ten years later - although "chill" as a verb with the same meaning lingers on. The expression "I'll school you" is long out of date, but when did it go out? Some expressions go out of style and then return, for example  "fly" meaning "good looking" has been going in and out for centuries. Is there a site that tracks this kind of thing? How about a book?
Comment: [Google Books Ngram Viewer](https://books.google.com/ngrams)
Comment: Unfortunately the Ngram Viewer tracks all instances, not the ones in the sense I intended. Thanks anyway!
Comment: You're looking for something that tracks specific meanings of phrases, not just their use in general? Good luck with that.
Answer: Most serious slang dictionaries put considerably more effort into identifying when a term arose than in trying to identify when it fell out of widespread or well-informed use. In part this is because documenting usage generally involves finding published instances of it—and noting that published instances of a term have declined or vanished is not an altogether reliable way to determine whether and when usage declined in the wild.
Not only is the dictionary maker in the awkward position of making a judgment about oral usage patterns on the basis of a written record, but the written record may yield multiple instances of usage of a slang term after it is essentially moribund in the wild, either because the recent written work is an academic inquiry into past slang or because it is a book set in the past and using then-current slang. On top of all that, slang isn't predictable or stationary. A formerly hip term like dig may survive for decades despite being used only by the least sophisticated demographic groups in society, only to emerge again as a hip term many years later. In short, it's difficult and dangerous to declare a slang term dead—and identifying when the term ceased to be used by the most sophisticated elements in society is highly subjective and (again) exceedingly difficult to determine.
A couple of sources make a serious effort to identify both when a term emerged and when (if ever) it fell into disuse. On the UK side, Eric Partridge, A Dictionary of Slang and Unconventional English, which passed through at least eight editions during the twentieth century, makes a serious effort to track when terms dropped out of use as well as when they came into play; Partridge's dictionary emphasizes British slang because Partridge was British, but he tries to address U.S.slang as well.
Among U.S. books, I think that J. E. Lighter, Random House Historical Dictionary of American Slang (two volumes, 1994 & 1997) does the best job of noting when a slang term has fallen into "historical use only." Unfortunately, Lighter's dictionary takes you only through the letter O; I don't think that the P–Z volume was ever published. Other resources such as the Dictionary of American Slang (which has been through four editions, first from Crowell and then from Harper Collins), the Oxford Dictionary of Modern Slang, and of course the early and monumental Slang and Its Analogues (from the turn of the twentieth century) do a nice job of documenting first (and subsequent) occurrences of the various slang terms, by date; but they don't concern themselves much with the obsolescence of such terms.
Comment: What a well researched answer. I will look for those books. Thank you.

Dating Colloquial Expressions and Slang


How to search content within sharepoint documents from MVC solution using C#?

Question: I have an MVC solution, I want to refer to a sharepoint site and do a document search (.docx, .xlsx, .pptx, .pdf, etc.), also search for content within the documents and list the results in a view, but I don't know how to do this, I was researching on the crawled documents, the SPSite object and the Client Object Model, but I didn't find any example that works for me, I'm new to Sharepoint and I not planning to become a sharepoint developer just want to implement this functionality. Any advice on what is the best way to do this?. Thank you so much for your responses.
Comment: How are you handling security? Do you want the MVC app to assume the security context of the logged in user, or is a service account identity ok?
Answer: You would call the SharePoint web services or if using SharePoint Online, you could also call the Graph web services.
https://docs.microsoft.com/en-us/sharepoint/dev/general-development/sharepoint-search-rest-api-overview
Here are some examples of the SharePoint web services:
https://yourServer/sites/yourSite/_api/search/query?querytext='sharepoint'&selectproperties='Title,Author'&StartRow=1&RowLimit=100

With refinement filters:
https://yourServer/sites/yourSite/_api/search/query?querytext='sharepoint'&selectproperties='Title,Author'&refinementfilters='fileExtension:equals("docx")'&StartRow=1&RowLimit=100

Example using OR's:
https://yourServer/sites/yourSite/_api/search/query?querytext='sharepoint'&selectproperties='Title,Author'&refinementfilters='or(fileExtension:equals("docx"),fileExtension:equals("pptx"))'&StartRow=1&RowLimit=100


after job interview and initial offer not hearing back from recruiter

Question: I had a phone interview, that moved into an in person. I had a questionnaire to fill and then the manager sent me an email to refill the questionnaire, which I did and replied with a thank you note. 2 days later I received a pre-offer to see if I would accept; he stressed that he was still going through some candidates he met the week before; I replied saying that I was very excited and that I had to questions (benefits and I had a week trip already schedule, if that would be possible to accommodate); he replied with the answer to the benefits and the nr of vacation weeks, also he would let me know soon. one week has passed and I don't know what that means and if I should follow up and how...any suggestions and/or insights? thanks
Answer: I'm not sure what a 'pre-offer' is, but it sounds like you are still in consideration for a position with this company.
It can't hurt anything at this point to reach out via phone or e-mail to inquire about where you stand.  Show them you are still interested!
Answer: Unless your scheduled trip was for a good reason, like visiting family or birth of a niece/nephew etc, it is a hard hand to play, before getting hired. And it might have pushed you to the bottom of the heap. But at this stage it doesn't hurt to contact the manager.
As a rule of thumb, all recruiters say that, if you are being offered a permanent position, you do not start asking for 1. How much money you are going to get; 2. how many vacation days you will have; 3. If you can work from home. These questions are reserved after you had a foothold in the office. Otherwise, they reflect badly on your priorities. Every company will pay you (or offer you) a decent compensation, some vacation time (even though in the first couple of years, it won't be much) and every company has a written or unwritten work from home policy. But if you concentrate on these aspects when manager asked you the question of "if you had any questions for him", it might not be perceived as good.
Comment: I disagree that a scheduled trip is a hard hand to play. In my experience it is not unusual at all - I have several times started a new job with a trip already booked and had to bring it up whilst discussing their offer. Some companies will treat it as unpaid leave, others will allow you to go into a negative leave balance, but I've never heard of anyone having a serious issue with it.
Comment: A pre-scheduled trip is not that uncommon.  It has happened to me twice with no problems at all from the new employer.  Many vacations have to be booked and paid for months in advance, and it's not realistic to expect a new employee to throw that money away.  I wouldn't bring this up during an initial interview, but it needs to be discussed after you receive an offer to make sure everyone know what's going on.
Comment: @Carson63000 consider that every company hires a person when they needed it most if not later than when they need him or her due to bureaucratic red tape. If you throw another wrench into the wheel saying that you will be gone in a very short time for a week or two and they have another viable candidate, guess which one they will take. If you are only one in the game or they are staffing at a leisurely pace, yes, you are correct. That is my point.
Comment: "you do not start asking for 1. How much money you are going to get;" - Really? If this isn't actually told to you when the offer is being made, surely it's need-to-know information when considering whether to accept the offer... ?
Comment: "All recruiters" might say that (but I doubt it) because they make money placing people into positions, but you get to set your own priorities.


Shifting of Energy levels in PN junction under Equilibrium

Question:
My question is during equilibrium is achieved under no biasing, why it is that in fermi level diagram representation fermi levels are raised in p type nd lowered in n type. Is it not possible we increase the fermi level of n type than p type.

If we finally look at the picture, it still confuses me and other readers too that fermi level then shown seems like fermi level of p type (Evp) and fermi level of
n type (Ecn) are still closer as they were individually were.. Some text says to see the scaling of energy levels of p and n level. But i am not satisfied.
Answer: You can find the position of Fermi level in two cases:
$$n_0=n_i\exp\left[\frac{E_F-E_{Fi}}{k_BT}\right]$$
$$p_0=n_i\exp\left[-\frac{E_F-E_{Fi}}{k_BT}\right]$$
Rearranging the two relations, We get:
$$\rightarrow E_F-E_{Fi}=k_BT\ln\left(\frac{n_0}{n_i}\right)$$
$$\rightarrow E_{Fi}-E_{F}=k_BT\ln\left(\frac{p_0}{n_i}\right)$$
For an $n$-type semiconductor, $n_0>n_i$ and $E_F>E_{Fi}$. The Fermi level for an $n$-type semiconductor is above $E_{Fi}$. For a $p-type$ semiconductor $p_0>n_i$ and from the second equation we see that $E_{Fi}>E_F$. The Fermi level for a $p$-type semiconductor is below $E_{Fi}$.

You can find the position for the fermi level explicitly thus can see whether it's how close it's to conduction or valence band.
Comment: My question is basically related to energy band diagram perspective...if you can answer that will be great. I am just aksing for the visual representation the doubt i am getting


Can the DLC's for destiny be shared between two accounts on ps3?

Question: I was wondering if the downloadable content for destiny can be shared between two different accounts on a PlayStation 3?
Answer: From the product's description:

Most PS3 downloaded content can be shared by other accounts on the same console where it was downloaded, as long as it's one of the two activated consoles associated with the downloading account. There are some rare exceptions, for example, DLC for Dungeon Siege III the game Final Fight Double impact is available for the purchasing account only.
The other exceptions are avatars which are tied to one account and one-time content like in-game cash/loot boxes which are tied to the account who purchased them only.
Answer: Anything purchasable can never be shared between accounts. It sort of makes sense for them. They would lose a lot of money if it was possible...
Comment: I played the map packs online, unless my memory is really failing me, either way I think a proper source for this would be worthwhile just for clarification, "there's no official method of content sharing" is a valid answer though
Comment: You definitely used to be able to 'share' call of duty maps dlc by signing into someone else's account and downloading it once, not sure if that's a valid option or if it still works though.
Comment: @ConnorLSW You used to, but only use it offline I think


Rails 3 XSS Escaping Breaks Plugins

Question: Is there a relatively easy solution to Rails 3 auto escaping to not break view-oriented plugins? I'm using table_builder which has an api along the lines of:
<code><%= calendar_for(args) do |table| %>
   ...
<% end %>
</code>
Unfortunately, rails goes through and escapes all the html generated from that plugin. Is there an easy way to avoid this behavior that doesn't involve me hacking on the plugin itself? I can't really wrap it in a raw() from what I know because its an erb block.
Answer: take care which fork you put in your gemfile, this one works with rails3 as a gem like demonstrated in the railscast: http://railscasts.com/episodes/213-calendars
https://github.com/jchunky/table_builder
use this in your gemfile
<code>  gem 'table_builder', '0.0.3', :git => 'git://github.com/jchunky/table_builder.git'
</code>

Rails 3 XSS Escaping Breaks Plugins


Improving a tag wiki entry not an option

Question: I am on a new private beta, and looking at tag wiki entries. I see some that are good fundamentally, but perhaps have a small error, like a spelling error. I can't figure out a way to improve the edit, either by accepting it, or trying to manually edit it. Is there a way to do this, and if not, can we make there be a way to do it?
Comment: Related: [How come I cannot improve, only accept/deny, tag excerpts through suggested edits?](http://meta.stackexchange.com/q/101663) (although the privilege thresholds are lower on private beta sites)
Answer: Trusted Users are allowed to improve tag wiki edits - but this bar is generally fairly high rep (iirc it's something like 1k in private beta, 4k in public beta).
The privilege is the same one as being able to edit tag wikis without needing approval (since improvement of suggested edits is essentially doing exactly that).


Why do all rays of light parallel to principal axis of a spherical mirror meet at focus?

Question: The reflected rays of light are not parallel or coinciding to each other, so they will have a unique solution(point of intersection) but why is that point of intersection half of centre of curvature and why meet on the principal axis?
Comment: This is a good exercise in geometry :)
Answer: First of all, this is not exact. Point of intersection is half way of radius only for small mirrors id est, small surfaces of mirrors with big curvatures. First of all, you need to draw geometric situation. If we agree that according to the law of reflection ray must reflect of the mirror as it is reflecting of the plane mirror which is represented by the tangent to the spherical mirror at the point of incidence and that the mirror is small that is, we cut a small surface of a big sphere, then this picture should serve as a proof...
If we agree that FE and BF are the same (almost) then we just have to prove that FE is the same as CF. But as you can see, BF is the same as CF. So CF=FE. Point of incidence is B. $\theta$ is the angle of incidence.
Answer: Parallel rays of light are not brought into sharp focus by spherical mirrors. They suffer a defect known as spherical aberration.
Getting a sharp image requires either a parabolic mirror (as commonly seen in Newtonian reflector telescopes) or an aspheric correcting lens in front of the mirror (as in Schmidt-Cassegrain telescopes).


Can you play Xbox 360 games multiplayer on the Xbox one?

Question: Me and a friend live long distance and want to play fable and halo together co-op but I have a one and she a 360.  So I was wondering if the backwards compatibility would let us play multiplayer.  Any answer is appreciated
Answer: Absolutely. An Xbox 360 game running on the Xbox One has full multiplayer support. From the Xbox One Backward Compatibility FAQ:

Can I do multiplayer gaming with friends who are playing the game on
  Xbox 360 or Xbox One?
Yes. For games that offer multiplayer gaming, you'll be able to play
  with others who own the title on Xbox 360.

Source: https://support.xbox.com/en-US/xbox-one/console/compatibility-with-xbox-360-faq#56a2123e4a7b479c9154fb304386099e


Word for not feeling part of a social or economic class

Question: Is there a word for a feeling or person that is part of a social class, but doesn't feel like they belong in that class? Say someone was poor their entire life and won the lottery. People they may associate with, and are friends with, poor people but may live around and attend functions with people in their economic class. In those cases they feel out of place.
Comment: You know, the most common is just **"don't fit in"**.  ("I was born and raised in Melbourne, but I don't fit in..." sort of thing.)
Answer: Not a single word but a common idiom...
be like a fish out of water
To feel awkward because you are not familiar with a situation or because you are very different from the people around you. source

All the other children in the school had rich, middle-class parents, and she
  was beginning to feel like a fish out of water.
Comment: You know, i think the OP is looking for someone who **feels like** a fish out of water, EVEN THOUGH IN FACT they **ARE** PART OF the social class in question. Is that right, OP?
Answer: Perhaps alienated

feeling that you do not belong in a particular society, place, or group

Another possibility is anomic

socially disoriented

This, however, usually refers to a breakdown in overall social mores or values.
Answer: Parvenu: "a person who has recently or suddenly acquired wealth, importance, position, or the like, but has not yet developed the conventionally appropriate manners, dress, surroundings, etc."
It is derogatory, and the sense of not belonging is legitimate emotion
Answer: This may be a case of impostor syndrome:

impostor syndrome … is a psychological phenomenon in which people are unable to internalize their accomplishments. Despite external evidence of their competence, those with the syndrome remain convinced that they are frauds and do not deserve the success they have achieved.
Comment: +1: I did not know of this, but it's interesting. I wonder if it explains Richard Nixon.
Comment: This works in the specific example the asker gave, but it wouldn't work in the opposite case—say, someone who used to be part of the jet set with a fancy Wall Street job, but then lost both job and money and is now living in a more humble environment, working as an accountant in a local firm, and feeling out of place in all this ordinariness.
Answer: Deracinate - to remove or separate from a native environment or culture
One year after winning the lottery, Jane felt deracinated; none of her old friends had much in common with her new lifestyle.
Edit Remembering that plants that have been up rooted often go through a transplant shock, I thought of culture shock.
Culture shock : a sense of confusion and uncertainty sometimes with feelings of anxiety that may affect people exposed to an alien culture or environment without adequate preparation
Comment: This describes the state of affairs the asker is looking for, but from the opposite side, so to speak: what the asker is looking for describes the feeling of not fitting into the new environment, while _deracinate(d)_ describes one's feeling towards one's original environment more. Good word nonetheless.
Answer: "to feel like an outsider" can fit also and it is a very common phrase.
Though it can be applied pertaining not only to changing environments but also a general feeling of not belonging to any class.
classlessness is a similar concept but less common. It can be used as "to feel classless".

outsider:  One who is isolated or detached from the activities or concerns of his or her own community.
classless: characterized by the absence of economic and social distinctions
Answer: You might try:
Socially isolated
Socially disconnected
Lonely
Outcast
Social pariah
Exiled
Non-conformist

Many of these have specific connotations, so choose the best for your needs.
Answer: Disconcerting is an adjective that describes this "out of place" feeling.
Going by etymology concert means harmonize, unite or cause to agree. Dis negates this meaning. So the person doesn't feel as a part of this group.
Comment: That's not what _disconcerting_ means. It means something that causes you (or others) to fell uncomfortable or ill at ease.
Comment: As far as my knowlege serves, this discomfort stems from not being able to relate to the group they are with.
Answer: You are looking for a word that means the opposite of class conscious.  I'm not aware of a single such term.
Google for class consciousness as well as class conscious for more about the general concept.
Comment: Whoever downvoted this, care to say why?


How to best avoid Multiple Inserts?

Question: I have a service application that monitors a directory changes.
The service application will monitor the directory closely. Here's how it does the thing:

Sleep X minutes
Scan through the directory, see whether there are new additions
Launch one thread per one addition
Repeat 1-3

One of the thing it does is that it will insert a record to a database. Now, since multiple threads can be running at the same time, it is entirely possible that two threads are inserting record at the same time.
I want to avoid this kind of simultaneous inserts; instead, I want those inserts to queue up, meaning that only 1 thread can access the database at a single point of time. Other service can't access the db when the there area already 1 thread  that accesses the database.
The reason I want this is because in the case of a power surge, I lost only one transaction instead of many.
I am thinking about using lock statement that locks out the database transaction. Is this the best approach?
P/S: I am writing a .Net service that talks to MySQL database.
Comment: Why do you start the service on a file change? Why not let the service watch the directory using FileSystemWatcher= If it's really a service, it should execute in the background and wake when something happens. Then you can control parallel inserts to your heart's desire...
Comment: I edit the question to make it clearer.
Answer: I would look first at the why you want to do this. Normally applications operate like that, there is no issue in 2 clients doing inserts at the same time (well, besides wrong approaches in the code).
Also the solution will vary with the scenario. One option is to have a microsoft message queue (MSMQ), and move the inserts out of those services, so the load of the inserts is controlled by the process that reads form the queue.
Update 1: I still fail to see why you want to avoid the inserts from running in parallel (and from what I read in the other responses I think others do to). I will quote 2 of your comments on this:

The reason I want this is because in the case of a power surge, I lost only one transaction instead of many.

Ant the other:

It's because before the insertion, there are other lengthy jobs that require parallelism. Only when during the insertion time, there is a need for sequential access.

If I read the first alone, I would actually think that's a reason to want them in parallel. You want to be done with them as fast as possible. Going sequential will actually increase the time to make the inserts, so there is more time where the power surge can occur.
Reading the second, it makes me think that you are probably more concerned in the effect of these processes running on parallel and the insert not getting into the db. This again means you want to be done with the inserts asap, so not a reason to do them sequentially.
For built-in support, you might have a case for a distributed transaction that also includes the file system (ms was looking at the file system thing, but I don't recall if they ever did something on the newer OS). Distributed transactions are kind of a pain to set up though (msdtc and access to the ports it uses).
A good path I have followed, is adding more info to the process to be able to tell where it failed. You might not even code an automatic recovery process yet, but at least you know you will have the info for sure to know something went wrong.
The simplest way is an insert at the beginning of the process and have a flag to signal when it was completed. If it is a long running process you might want to have something more like an status you keep updating to be able to tell in which step it failed. An alternative is writing the status to the file system.
In any case it will only tell you that the last step that completed successfully, not whether the current step was or not able to be completed. This is what makes the retry logic a bit more complex, as you can't just continue where it stopped, you have to check whether the last step was or not done, and that depends on each step.
Ps. if the above is the case, it is hard to tell from the question. You might want to open a different question about long running processes and/or automatic retries.
Answer: A database is meant to allow multiple processes to insert data at the same time, so I fail to see your problem. Do you get an error?
[EDIT] You fear a power surge. Where? On the server or the client? Here are your options:

Server crash. Just have the clients check for the error code for "connection lost" and have them retry their insert until it succeeds. To figure out this error code, either shut down the server in the middle of an insert or pull out the network cable of your client (or both; sometimes, you get different errors for unexpected network problems).
Client crash (much more likely, since clients are usually cheap PCs. If users have access to it, it will eventually be infected with a virus or the file system will become corrupted, it will run out of RAM, someone will install something "cool" which destroys a vital DLL, or whatnot). In this case, you have to start the client again, check what has already been inserted (using an application key) and continuing from there.

An application key is an ID for a row that is related to your business process. For example, if you sell cards, the app key could be the name of the car and the name of the customer plus the timestamp.
Comment: I dont want simultaneous insertion because if there is a power surge, I don't want all the insertion goes down the drain.
Comment: The same will happen when you do it sequentially ... So I don't really see how your approach will do you any good...
Comment: Literally *decades* of work have gone into making databases good at dealing with this sort of thing (look up "ACID"). The database is *not* going to be your problem.
Answer: Why do you create a new thread per insert? Why not simply loop over the inserts? Threads are only necessary when you need parallelism; in you case, this seems to be the exact opposite of what you want.
[EDIT]

It's because before the insertion, there are other lengthy jobs that require parallelism. Only when during the insertion time, there is a need for sequential access.

Then have those threads report back to the main thread who collects the results and inserts them in a loop.
Comment: It's because before the insertion, there are other lengthy jobs that require parallelism. Only when during the insertion time, there is a need for sequential access.
Answer: If you have multiple windows services installed watching the same folder or if you have a multi-threaded windows service then you will get multiple simultaneous inserts. Otherwise you don't need to worry.
Comment: Yup, this is the case here: I have multiple services running at the same time.
Answer: I think the best option here is to follow Aaron's suggestion and have the threads report back after processing each file; then update the database from a single-threaded 'manager' class.
If that is not an option you could use lock/synclock around the code that updates the database.
However, one of your comments says there are multiple services running.  Is that true?  Multiple Windows Services watching the same directory AND multi-threading the processing?  Why?  You'll have to better defend that architecture to get better responses, I think.
Answer: As many said before: this is a bad thing to do. It will artificaly create a bottleneck.
But if you really want to do it, here are your options:
a) create a primary key on the table. You should do that anyway for a clean db design. In order to check the validity of the PK the database has to use locking which will force your inserts into a sequence.
b) if a) isn't enough of a bottleneck for your purpose you should use a separate lock. Depending on your environment there might be a special api for this (e.g. the java concurrency api).
c) If that isn't available or you don't like it, you can use the locking mechanisms of the database: create a table with just a single row in it. On each insert do the following:
- read the special table 'for update'. This will (in most database setups) keep any other session from doing the same.
- do the insert.
- commit. This will release the lock and allow the next session to proceed.
And just as a reminder: This is exactly the opposite of what one tries to achieve normally: Allowing as many threads as possible to work without interference

How to best avoid Multiple Inserts?