lighting – How to make an illuminated body landscape with minimal equipment?

Things to consider about your picture:

  • The light comes from above and very easily in front of the subject. I bet if you drew a line straight up from his mouth you would hit the light.
  • Seems to be a single light source. The shadows don't seem to be filled in, which indicates that a fill flash or reflector was used
  • Shadows are defined but still have blurry edges, indicating that a small light source was used, but not necessarily a point source. Maybe a little lightbox was used
  • The light almost seems to overexpose the edge of the head and falls off at the knees (assuming the drop is in the camera and not in the mail). I would imagine that the light source is about a meter above the subject.

I would suggest that you shot similarly to this one. If your lamp base is not big enough, you can creatively attach the lamp to the ceiling. The light should be directed straight down and positioned directly in front of you.

You don't mention what camera and lens you have, so I'm assuming a new DSLR and a kit lens (18-55mm). Switch your camera to manual mode and choose f / 5.6 for the aperture (the lenses sharpen a few steps down from the maximum aperture). You have to play with ISO and shutter speed to see what works …

30W is unfortunately not that bright. On the sales page for your lamps you can see how they light a sock from a foot or so away. This is what these lights are designed for: illuminating something small and fairly close … small objects, headshot portraits, etc.

Place an object approximately where your shoulders would be in the frame, read a reading through the camera, and set the shutter speed after setting ISO to 3200. For example, if a speed of 1/500 is good – then we know that we can reduce your ISO. The shutter speed should be in the range of 1/15 to 1/60 or faster, using the lowest ISO you can get. Note that you want to use your camera's Mirror Lock Up function in this area.

Because of the low light intensity, you may have to compromise by using a wider aperture at the expense of sharpness. I won't know until you measure!

I would remove the lightbox for this shot and see how it turns out. If your shadows are more defined than your goal, you need to dim the light (use the softbox). The limitation here is that your softbox can do the lighting also soft … this would mean that you need a smaller box or want to try some homemade light softening solutions.

Due to the low light output, it may not be possible to adequately illuminate the head, shoulders, trunk and legs. If it gets worse, you can always lower the light and make separate exposures for the head, trunk and legs and then fuse them together. It would be nice to do everything at once, of course, but if you lack the equipment, give it up again in the post ;-).

Should I somehow isolate myself as I have white walls so that the light is not reflected?

Yes. Your studio should be dark enough so that the camera only records the light that you want it to be shot from the direction it should come from. Most studios use dark / black painted walls, ceilings and floors for the very reason you describe: white walls reflect the light. You can avoid this by using a very large and open space or by wrapping yourself with dark fabric (think of a human light box).

Algorithm analysis – How can you compare n m-dimensional points with minimal time complexity?

Suppose there are four points (n = 4) that are four-dimensional (m = 4). Suppose these points are – A (4,1,1,1), B (3,2,1,1), C (2,3,3,3), D (1,4,4,4 ). What is the best data structure to compare all points based on their values ​​in corresponding dimensions? The goal is minimal time complexity. (Practically n >> m).

Minimal $ 2 $ full hypergraph

We say that a hypergraph $ H = (V, E) $ is $ 2 $complete if for everyone $ a, b in V $ there are $ e in E $ With $ a, b in e $,

If $ H = (V, E) $ is $ 2 $-complete, is there $ E_m subseteq E $ so that $ (V, E_m) $ is $ 2 $-complete, but for everyone $ e in E_m $ we have that $ (V, E_m setminus {e }) $ is no longer $ 2 $-Complete?

Minimal polynomial – MMA has an error in the calculation of the minimal polynomial of a rational number

The minimal polynomial of Power(2, (3)^-1) (-(1/2) + (I Sqrt(3))/2) The Python minimal_polynomial function can get the result as x^2 + 2^(1/3)*x + 2^(2/3)
(In Python means ** ^)
Enter image description here

import os
import sympy as sy
from sympy import minimal_polynomial, sqrt, solve, QQ, Rational

from import x, y, z
s = minimal_polynomial (2 ** Rational (1, 
     3)*(Rational (-1, 2) + 
      Rational (1, 2)*3 ** Rational (1, 2)*sqrt (-1)), x, 
   domain = QQ.algebraic_field (2 ** Rational (1, 3)))
print (s)
print (sy.latex (s))

But MMA cannot get the result.

MinimalPolynomial(Power(2, (3)^-1) (-(1/2) + (I Sqrt(3))/2), x, 
 Extension -> Power(2, (3)^-1))

Data structures – number of different binary search treasures with minimal height

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How can you make DDL changes to large tables and cause minimal server and object conflicts?

I work with many large tables (billions to dozens of billions of records) in a database that I recently inherited. I see a few clear DDL changes that would benefit the database use cases, but I find it difficult to implement because the database can only afford minimal conflicts. (If a heavy query runs for more than a minute or two, it must be canceled.)

Even during a maintenance window, these changes would be far too long and would exceed my allotted time (at most 1 hour, since there are actually no free hours).

The changes I want to make include creating indexes, adding permanent columns, creating indexed views, and general index optimization. If there was a way to do one of these operations iteratively and pause between iterations, I could take all the time because I can at least allow other processes to run in between instead of building a backlog.

The only idea that comes to my mind is if I maintain a copy of the database on a separate server where I can make DDL changes and then point my applications to that server. Then update the first server with the DDL changes so that it is in sync. The next time I need to update, I can repeat the process.

Polynomial approximation (in $ L ^ 1 $ norm) at minimal cost

Define that costs of a polynomial $ sum_ {i = 0} ^ N a_i x ^ n $ his $ sum_ {i = 0} ^ N | a_i | $, To let $ g: (0,1) to mathbb {R} $ be a function to be approximated – let's say $ g (x) = 1 / x $ if $ e ^ {- 1} leq x leq 1 $. $ g (x) = 0 $ if $ 0 leq x <e ^ {- 1} $, (This function occurs in practical contexts.) We are interested in polynomials $ P _ + $. $ P _- $ so that $ P _- (x) leq g (x) leq P _ + (x) $, We define that tightness $ epsilon (P) $ of $ P $ to be fair $ epsilon (P) = epsilon = int_0 ^ 1 | P (x) -g (x) | dx $,

For given $ epsilon> 0 $ and $ N $ What are the polynomials? $ P _ + $. $ P _- $ the tightness $ leq epsilon $ and minimal cost? What are these minimal costs $ c _ + ( epsilon, N) $. $ c _- ( epsilon, N) $? What if we allow graduation? $ N $ be arbitrary? (In other words, what are $ c _- ( epsilon) = inf_N c _- ( epsilon, N) $ and $ c _ + ( epsilon) = inf_N c _ + ( epsilon, N) $?)

(Is there an easy way to see the right size of?) $ c _ + ( epsilon) $ and $ c _- ( epsilon) $?)

(Bonus question: what happens if you allow? $ P _ + (x) $. $ P _- (x) $ be a linear combination of breaking forces $ x ^ r $. $ r geq 1 $?)

Digital Ocean – How can a minimal Golang server be deployed on an Ubuntu VPS?

I built one Go a web server and an API server that I want to run on the same server with one MySQL Database.

I can't find any resources that explain how to run a Golang app with go modules directly on the VPS server. I don't want to build the server on the VPS.

Can anyone refer to resources to explain how to do this in a minimalist way and possibly using nGinX but any webserver will do it?

SQL Server – What preventive measures can be taken to deal with this scenario with minimal data loss

I am SQL Server DBA and encountered strange scenario, our cluster had 10 nodes 5 primary 5 secondary each node had SQL role …. Example Ams1pd11 to Ams1pd15 are primary .. and Ams3 side of PD11 to 15 was secondary … In this scenario, the behavior of the entire cluster after 2 node failure was unusual and all node availability groups were inaccessible, resulting in multiple customer failure.

Explanation of the real-time scenario, how it started when I was on the shift ….

Ams1pd12 has failed and hosted primary server A.
So role A on the best possible node was automatically canceled and he chose Ams1pd11.

Ams1pd11 already had a role, e.g. B. B
Now Ams1pd11 hosted both A and B when Ams1pd12 failed

Since both primary roles were on a node, there was a risk of balance. I failed over the B node to one of the secondary nodes on the Ams3 side. Now it was balanced and I was just about to investigate on Ams1pd12 why it failed and everything. ,

But suddenly the Ams1pd11 node also failed and the role did not fail and was stuck there …

Now 2 out of 10 nodes had failed and one role was stuck, so the customers in this role were affected.

We troubleshooted the same issue at Microsoft and found that other nodes were shown by the availability group for all blocked nodes and were not opening and blocking when expanding.

This affected all nodes in this cluster and therefore our backups were stopped.
There was data loss …

The stuck role and the customer on this node only had to accept a data loss of 15 minutes because the service for us and for them also failed at the same time

The nodes that appeared and AG groups were inaccessible. It was strange that the users who were already logged in could change the data. Only new connections were rejected. But the old connection was still active.

So if the problem started and the backup was stopped at 7am, most customers could access the database until 6pm, resulting in 11 hours of data loss.

Manual database recovery took a lot of effort …
These online nodes were easy to restore because we only had to attach the database databases while migrating data and log files for databases with deadlocked roles. We had to restore it manually.

Please suggest the best strategies to follow in this type of disaster to achieve rapid recovery.