Research – Cultural differences in QR code usage between Eastern and Western countries

Although I have had limited travel experience in Asian countries like China, Taiwan, Japan, and Korea, it is obvious that in many cases there are QR codes in applications such as transportation and retail, compared to Western countries like the US. Australia and the UK.

Is there a specific reason for these differences, at least when it comes to something that can be explained by technology and business constraints rather than cultural differences? And when it comes to cultural differences, what is the reason and how is it applied in countries where there is a good mix of eastern and western cultures like Singapore and Hong Kong?

Numeric – Legendre polynomials that have been evaluated with large differences

I'm dealing with Legendre polynomials, including the first, the second, and the associated ones. However, I found the following:

in the[252]: = N[LegendreQ[30, 0, 3, Cosh[1]]]out[252]= -0.0681152

and:

in the[251]: = LegendreQ[30, 0, 3, N[Cosh[1]]]out[251]= 1.18183 * 10 ^ -14 + 0

I do not know why the result is so different.

I tried to draw the graphic from $ LegendreQ[30,0,3,Cosh[x]]$ With $ x $ from $ {0,3} $The graphics showed me almost zero.

I do not know if that's a mistake or something. Need help!

finite differences – simplification: Taylor series extension $ U (x, t) $ around point $ bigg (x + frac {1} {2} h, t bigg) $

I have to expand that $ partial_x ^ 2U (x, y) $ in the form of a finite difference expression around the point (x + frac {h} {2}, t) instead of the usual one $ (x, t) $ Point. That means you get:
$$ partial_x ^ 2U (x, t) = frac {1} {2h ^ 2} left[ Ubigg(x+frac{3h}{2},tbigg) – 2Ubigg(x+frac{h}{2},tbigg) + Ubigg(x-frac{h}{2},t bigg) right] $$
Now I'm good at extending each of these three terms … but I'm lazy and want to look for a better alternative. I have seen books that do the following:
$$ U bigg (x + frac {h} {2}, t bigg) = frac {1} {2} bigg[ U(x+h,t) + U(x,t) bigg] $$
The above pretty cool value (if true) would then be able to write the expression of the finite difference as:
$$ partial_x ^ 2U (x, t) = frac {1} {4h ^ 2} bigg[ U(x+2h,t) – U(x+h,t) – U(x,t) + U(x-h,t)bigg] $$
just by pointing it out
$$ U bigg (x + frac {3h} {2}, t bigg) – 2U bigg (x + frac {h} {2}, t bigg) + U bigg (x – frac {h} {2}, t bigg) = frac {1} {2} bigg (U (x + 2h, t) – U (x + h, t) – U (x, t) + U ( xh, t) bigg) $$
Does that really work … I do not think so. I've written an extension script for Taylor series with Sympy, and it shows that the extensions are the same. Why is that? Did I do something wrong? Please help me to find the mistake.

I really do not feel like expanding the original expression by hand, and it would be great if there was a simpler version than the one I suggested.

Differences between Hot Standby and Warm Standby Postgresql?

I'm confused about the differences between the database replication methods mentioned in a postgres wiki page, which is best for the normal situation?

  1. Warm standby / continuous archiving / log shipping

    offers high availability

    http://www.postgresql.org/docs/current/static/warm-standby.html

  2. Hot Standby / Binary Replication / Streaming Replication

    Used for read-only queries

    https://wiki.postgresql.org/wiki/Hot_Standby

    https://wiki.postgresql.org/wiki/Binary_Replication_Tutorial

  3. PITR

drush – How to check the differences in the configuration

Is there a way to find differences to the configuration in Drush?

I checked the list of drush 8 config commands and could not find anything.

The reason I need this is because I have a site that does Behat testing through CircleCI, and sometimes I have to import the configuration more than once. So I wanted to write a bash script that Drush uses to check for configuration differences. If so, the configuration is automatically re-imported in a loop until no differences occur.

I'm on Drush 8 because the Behat extension only supports Drush 8.

Compact Cameras – What are the sensor differences between the Panasonic Lumix DMC-LX7 and the DMC-LX15 practical?

The sensor of the Panasonic Lumix DMC-LX15 is 2.74 times larger than the sensor of the Panasonic Lumix DMC-LX7. That's a big advantage.

If two sensors use the same technology, a 2.8X sensor would almost be the same as the other two stops Advantage in terms of signal-to-noise ratio (SNR or S / N ratio). By comparison, full-screen sensors are about 1.5 times larger than APS-C sensors and thus enjoy an approximate rating a stop Difference if both use the same technology.

The pixels of the LX15 are slightly larger than the pixels of the LX7. This means that the LX15 is 2.74X as large as the LX15 compared to the 10X LX7. While megapixels are not the nuts and bolts of what some people make out, more megapixels allow for larger display sizes before a picture appears pixelated.

The LX15's 24-72mm (35mm equivalent) f / 1.4-2.8 lens compares pretty well with the LX7's 24-90mm (35mm equivalent) f / 1.4-2.3 lens. It is not zoomed out so far and it is one little At 72 mm (35 mm equivalent) slower than the older camera, it is 90 mm (35 mm equivalent), but only about two-thirds of a stop.

Combine the differences between the sensor sizes and the maximum aperture sizes of the two cameras. The newer LX15 has one 35 mm equivalent opening¹ of f / 3.8-7.6 compared to LX7 with a 35 mm equivalent opening¹ of f / 6.4-10.6. This means that at 24 mm (equivalent to 35 mm) you can expect a performance advantage of around four-thirds and at 72 mm (equivalent to 35 mm) with the LX15 compared to the LX7 an approximate stop.

In other words, in terms of low light performance, the LX15 is similar to the LX7 like an FF camera with an APS-C camera. That's a big difference in low light.

This is also true before taking into account the potential impact of the four-year technological difference between the LX7 published in 2012 and the LX15 published in 2016. This can be a big factor as the sensor technology improvement has increased a bit. In general, comparable models between 2008 and 2012 are expected to show more improvement between 2012 and 2016 than comparable models. But every case is different.

As far as the price differences are concerned, the cheapest FF cameras are at least twice as high as the cheapest APS-C cameras. The Canon EOS 6D Mark II is offered for $ 1,800, but currently sells for about $ 1,300 at an immediate $ 500 discount in the United States. The Canon EOS 77D lists for $ 750 and costs about $ 700. (The 77D is quite similar in terms of features and controls to the 6D Mark II, both introduced in 2017, both have similar 45-point AF systems, etc.) Rebel / xx0D models can be cheaper, but they do not the same level of controls and other functions.)

Is securing the future a big factor here?

There is no proofing for the future, especially when it comes to cameras. When a model comes on the market, the replacement for this model is already anticipated by many camera-driven gearboxes before photography.

¹ Equivalent aperture (in 135 film terms) is calculated by multiplying the lens aperture by the crop factor (a.k.a., focal length multiplier).

Configuration Management – How do I check for differences in configuration with drush 8?

Is there a way to find differences to the configuration in Drush?

I checked the list of drush 8 config commands and could not find anything.

The reason I need this is because I have a site that does Behat testing through CircleCI, and sometimes I have to import the configuration more than once. So I wanted to write a bash script that Drush uses to check for configuration differences. If so, the configuration is automatically re-imported in a loop until no differences occur.

I'm on Drush 8 because the Behat extension only supports Drush 8.

Source Control SQL Server multiple shards with minimal differences

One of the database systems that I work with (I call it Database A) has been essentially split into 3 schemaid-style copies. This was easy in Source Control, and if a change was made to one of the copies, all copies would be copied.

A few months ago, a change was made. A new database was created (not Sharded, I call it Database B), and in Database A, a view was created to point to Database B.

The problem is that the view between the three instances of database A is not the same. Database B has three schemas: one for each of the three instances of Database A. The difference in view between the three instances is just to show the different schemes.

We use TFS2015 for source control. It would be too big to change this DB structure, but I am not sure how to do the source control of the view, which must be different between the three instances of database A.

Is there a way to source control without having three copies in TFS?