## Is it allowed to spend a night in the first entry country before moving to the main destination?

I have booked to spend a night in the first entry point which is Germany. Then in the second day I’m going to move to the main destination (Switzerland), where my visa has been issued, by car.Is that illegal and I have to have a flight to the main destination at same time?

## Intersection of sphere with triangle containing moving vertices

First off, apologies if I cannot properly articulate my question in the most formal way. However, I believe my question should be simple enough to grasp anyhow.

In $$\mathbb{R}^3$$, I would like to determine the time of contact, if any, between:

• An unmoving unit sphere, whose center is at the origin
• A triangle, each of whose vertices follow independent, linear motion from $$t = 0$$ to $$t = 1$$. In other words, each triangle vertex has a start and end position, which are linearly interpolated by $$t$$.

The sphere may touch the triangle on a vertex, an edge, or on the triangle’s surface. Vertex testing is simple enough as it’s analogous to static line segment-sphere intersection.

For edge testing, parameterizing a line-sphere intersection test by $$t$$ appaers to lead to solving a degree 4-polynomial, which isn’t ideal. I believe that doing the same for triangle surface testing (parameterizing a sphere-plane intersection with $$t$$) would lead to solving a 6-degree polynomial.

Would there be any applicable non-analytical methods to approximate the intersection (other than directly approximating the polynomial roots)? Or maybe there is an analytical method that I’m not thinking of. In addition, would further constraining the motion of the triangle potentially simplify a solution?

## Can not intall software after moving the system

My old system can isntall virtualbox,but my new system in ssd can not install virtualbox. Is there some easy way to repair the new system by the old one? I use Ubuntu 18.04.And I move as follows:

1. Partition the ssd,and get a free space called sda1.
2. I use dd if=/dev/sdb9 of=/dev/sda1 copy the linux file system to sda1 in new disk.
3. I changed the UUID
4. I use boot repair to install the grub.

Then the new Ubuntu works,but I can’t install software now,and I compared my new files with my old files,I find they are different.

Maybe I lost some files,can I use my old system or reinstall the module again to recover the apt-get install module?

EDIT: the problem is whenever I install the software by sudo apt-get install.It says:

dpkg: warning: files list file for package 'binutils-common:amd64' missing; assuming package has no files currently installed dpkg: warning: files list file for package 'binutils' missing; assuming package has no files currently installed dpkg: warning: files list file for package 'binutils-x86-64-linux-gnu' missing; assuming package has no files currently installed dpkg: unrecoverable fatal error, aborting:  files list file for package 'libgomp1:amd64' contains empty filename E: Sub-process /usr/bin/dpkg returned an error code (2) 

## Creating slices and moving services

Is there anywyay I can create a new slice in systemd with the default slices(user.slice,system.slice)? If so, what is a good way to move new and default services to the new slice?

## Moving On Premise Infrastructure into Azure/AWS

I am new to Server Fault (coming from StackOverflow) and please tell me if this is not the right place to ask this general question. Basically our company is trying to move away from an on premise infrastructure to a cloud infrastructure. We are considering Azure/Aws for this.

Currently we have some virtual machines running on our local server. A Server with the Domain Controller, a File Server, a Database Server, and one for our websites with IIS installed. Our Exchange we already moved to Exchange online with Office365 and Azure Active Directory,

However, we also wanted to move the other servers into the cloud. I thought that we can create Virtual Machines on Azure for example and join all of them to the same Active Directory by connecting them to the same Virtual Network. Would this even be the right approach?

Now, saying that we would set up everything like this, if I informed my self correctly, we would need to set up a site-to-site connection so that we can access everything on these servers from our on premise network. But is it even possible to join the Active Directory that is running on a Domain Controller on a Virtual Machine in Azure from our on premise network?

Another question, how is the performance? Of course it will be slower than having everything in house, but our files are not super large and the requests aren’t too many.

Once again, I am net to this stack exchange and I am mainly a programmer. We are a small company though and I am trying to modernize our infrastructure a little bit. I am not an expert in networking, therefore I am asking you experts here hoping to gain some knowledge. So please be nice:)!

## Singularities of curves that are moving

Let $$k$$ be an algebraically closed field, let $$d\ge 2$$ be an integer and let $$f,g\in k[x,y,z]$$ be two homogeneous polynomials of degree $$d$$ without common factor.

We want to know what are the singularities of the curve $$C_{[\lambda:\mu]}$$ given by $$\lambda f+\mu g=0$$, for a general $$[\lambda:\mu]\in \mathbb{P}^1$$. If a point $$p\in\mathbb{P}^2$$ is a singular point of the curves $$C_{[1:0]}$$ and $$C_{[0:1]}$$ given by $$f=0$$ and $$g=0$$ then it is of course singular for each $$C_{[\lambda:\mu]}$$. If $$\mathrm{char}(k)=0$$, then by Bertini there are no other singularities. If $$\mathrm{char}(k)=p>0$$, it is false: take for instance $$f=x^p$$ and $$g=y^p$$. Are all counterexamples of this type ? One can of course replace $$p$$ by a power of $$p$$ and maybe do some more general examples. For instance, if $$d<2p$$, is the case $$f=x^p$$ and $$g=y^p$$ the only possibility (up to change of coordinates)?

## Sharepoint 2013: Moving a field o be side by side with another field doesn’t save it

in an list/EditForm.aspx, I have the following code to copy/paste a field to another place:

var dest = $('span[title="MyTitle"]').parents("tr:first"); // place to be copied var source =$  ("input[id*='IsPositive']").parent(); // what to copy dest.append('<td><span id = "NewIsPositivePosistion"> &nbsp;&nbsp;&nbsp; positive :&nbsp;&nbsp; '+ source.html() + "</span></td>") //append it source.parents("tr:first").remove() // delete the old place 

The field and its value is been copied but when i change the copied’s value and press Save, its value is not been saved. Any ideas?

## Moving Data from .DLL to an .Exe in C#

I’m rewriting a C# DLL to send a file directly to a c# Executable residing on the same machine. Currently this DLL basically saves the File to a Location then the Executable Application picks that file up using a File.ReadAllText() command.

What would be the best way to achieve functionality? Currently I have been researching AnonymousPipes in C# and have been able to easily transfer text files over the pipe to the executable. What if I want to transfer an image file for example?

So far I have attempting using C# AnonymousPipes.

                using (PipeStream pipeClient =                     new AnonymousPipeClientStream(PipeDirection.In, args[0]))                 {                     pipeClient.ReadMode = PipeTransmissionMode.Message;                     using (StreamReader sr = new StreamReader(pipeClient))                     {                         string myData = sr.ReadToEnd();                     }                 }             } 

## Moving to a field of low abstraction

What are examples of mathematicians who were initially primarily working an area of (comparatively) high abstraction and then started working primarily in an area of (comparatively) low abstraction?

Here, the level of abstraction is defined as follows: take a paper of yours, choose the object of primary interest, give its definition, then give a definition of all the terms entering the definition, and so on and so on before you arrive at the “atomic” notions (which for most mathematicians will be sets). The number of iterations is the level of abstraction.

An anti-example is Barry Mazur, who started working in geometric topology and then moved to arithmetic geometry and some tech-intensive number theory.

## Probabilistic Weighted Moving Average (PEWMA) df.iterrows loop in python slow? Can Pandas speed it up?

Im implementing the Probabilistic Exponentially Weighted
Mean for real time prediction of sensor data in pandas but have issues with optimising the pandas notebook for quick iterations.

Is there a more optimal ways to completely remove the for loop as it currently runs longer than expected to… How can I take advantage of apply() etc here…

import sys import datetime import time  import pandas as pd import io import requests  Blockquote  import numpy as np     from itertools import islice from math import sqrt from scipy.stats import norm  # create a DataFrame for the run time variables we'll need to calculate pewm = pd.DataFrame(index=df.index, columns=['Mean', 'Var', 'Std'], dtype=float) pewm.iloc[0] = [df.iloc[0][value_col], 0, 0]  t = 0  for _, row in islice(df.iterrows(), 1, None):     diff = row[value_col] - pewm.iloc[t].Mean # difference from moving average     p = norm.pdf(diff / pewm.iloc[t].Std) if pewm.iloc[t].Std != 0 else 0 # Prob of observing diff     a_t = a * (1 - beta * p) if t > T else 1 - 1/(t+1) # weight to give to this point     incr = (1 - a_t) * diff      # Update Mean, Var, Std     pewm.iloc[t+1].Mean = pewm.iloc[t].Mean + incr     pewm.iloc[t+1].Var = a_t * (pewm.iloc[t].Var + diff * incr)     pewm.iloc[t+1].Std = sqrt(pewm.iloc[t+1].Var)     t += 1 $$$$ `