## Computational complexity in Boolean network

An Boolean control networks can be expressed as $$$$\label{ControlBN} \left\{\begin{array}{l}{x_{1}(t+1)=f_{1}\left(x_{1}(t), \cdots, x_{n}(t), u_{1}(t), \cdots, u_{m}(t)\right),} \ {x_{2}(t+1)=f_{2}\left(x_{1}(t), \cdots, x_{n}(t), u_{1}(t), \cdots, u_{m}(t)\right),} \ {\vdots} \ {x_{n}(t+1)=f_{n}\left(x_{1}(t), \cdots, x_{n}(t), u_{1}(t), \cdots, u_{m}(t)\right),} \ \end{array}\right.$$$$ where $$x_i,~i=1,\dots,n,$$ are state nodes, $$x_i(t)\in\{0,1\},\,i=1,\cdots,n$$ are the value of the state node $$x_i$$ at time t. $$u_i,~i=1,\dots,m$$ are control nodes, $$u_i(t)\in\{0,1\},\,i=1,\cdots,m,$$ are the value of the state node $$u_i$$ at time t, and $$f_i:\{0,1\}^{n+m}\rightarrow \{0,1\},\,i=1,\dots,n$$ are Boolean functions.

Consider the above system, Denote its state space as $$\mathcal{X}=\{(x_1,\cdots,x_n)|x_i\in\{0,1\},i=1,\cdots,n\}.$$

Given initial state $$x ( 0 ) = x^0\in \mathcal{X}$$ and destination state $$x^d\in \mathcal{X}$$. Destination state $$x^d$$ is said to be reachable from the initial state $$x^0$$ at time $$s>0,$$ if there exists a sequence of controls $$\{u(t)|t=0,1,\cdots,s-1\}$$, where $$u(t)=(u_1(t),\cdots,u_m(t))$$, such that the trajectory of the above system with initial value $$x^0$$ will reach $$x^d$$ at time $$t=s.$$

The above system is said to be controllable, for any $$x^0,x^d\in \mathcal{X},$$ $$x^d$$ is reachable from $$x^0.$$

$$M$$-step Controllability Problem is defined as

Input: Given an Boolean Control Networks with $$n$$ state variables $$x_1,\cdots,x_n,$$ $$m$$ controls $$u_1,\cdots,u_m,$$ Boolean function $$f_1,\cdots,f_n:\{0,1\}^{n+m}\rightarrow \{0,1\}.$$ Given constant $$M.$$

Problem: for any destination state $$x^d$$ and initial state $$x^0$$, whether or not there exists a sequence of controls $$\{u(0),\cdots,u(M-1)\}$$ such that $$x^d$$ is reachable from $$x^0$$?

In order to solve this problem, I convert the problem into logical form as following:

$$\begin{equation*} \begin{split} &\forall x_1(0)\cdots\forall x_n(0)\forall x_1(M)\cdots\forall x_n(M)\exists u_1(0)\cdots\exists u_m(0)\exists x_1(1)\cdots\exists x_n(1)\cdots \exists x_1(M-1)\cdots\exists x_n(M-1)\ &\exists u_1(M-1)\cdots\exists u_n(M-1)~~\bigwedge_{i=1}^{n}(f_i(x(0),u(0))\leftrightarrow x_i(1))\wedge \bigwedge_{i=1}^{n}(f_i(x(1),u(1))\leftrightarrow x_i(2))\wedge \cdots\wedge \ &\bigwedge_{i=1}^{n}(f_i(x(M-1),u(M-1))\leftrightarrow x_i(M)).\ \end{split} \end{equation*}$$

According to such expression, I can prove the upper bound of the problem. But I have no idea about how to prove it is $$\Pi_2^p$$-hard.

## USB flash drives sharing on computer network [closed]

https://en.wikipedia.org/wiki/USB

https://en.wikipedia.org/wiki/Computer_network

Can we share USB flash drives on a computer network?

Example : USB flash drives connected to a local Windows/Mac/Linux os machine is part of the computer network. The contents of the USB flash drives to be shared with other computers.

Can this be implemented?

## Calling from mobile phone without using the cellular network

This has been in the news: https://www.wired.com/story/fcc-fines-wireless-companies-selling-users-location-data/

Is there a way to make calls without using cell towers?

Also in this context: is it true that if one uses wifi only for calling, then the location is not sent?

## Firewall Settings for home network

What should the settings be on a home firewall for maximum security (the following options are turned off, should I turn them on?)

(1)Drop incoming ICMP Echo requests to LAN (2)ESP Header Forwarding (3)Authentication Header Forwarding (4)ESP ALG

(Only options are On and Off)

## Why don’t they use all kinds of non-linear functions in Neural Network Activation Functions? [duplicate]

Pardon my ignorance, but after just learning about Sigmoid and Tanh activation functions (and a few others), I am wondering why they choose functions that always go up and to the right? Why not use all kinds of crazy input functions, those that fluctuate up and down, ones that are directed down instead of up, etc.? What if used functions like those in your neurons, what is the problem, why isn’t it done? Why do they stick to very primitive very simple functions?

## Given a plot of a network Graph[] how can the {x,y} screen coordinates be output?

Is there a general way to get the screen or "world" coordinates for every vertex in the graphic output of something like this?

Table[Graph[Table[i \[UndirectedEdge] i + 1, {i, 20}],    GraphLayout -> l,    PlotLabel -> l],  {l, {"CircularEmbedding", "SpiralEmbedding"}}] 

Trying to build an algorithm to generate novel layouts and want to use a large amount of other algorithms for training data.

## Remote debugging android app from another computer on different network

Is is it possible for Android development to remote debug an app from another network? I am not talking about WebView/Web Pages debugging but as stated here, as this page talks about remote debugging a WebView or web pages opened in any app and also I don’t think it will work on if device and computer are on different networks.

My scenario is that if Device A is connected to Computer A on Wifi A and I want to debug the app running on Device A from Computer B on Wifi B.

There is option to connect your device using the ADB wireless debugging using TCP-IP, but that requires the Device and Computer to be on the same network, but in my case device and computer are on another network.

## Should you let yourself ssh into every machine in your network?

I am wondering how you should setup your network (AWS) so you can debug different things that might occur. Obviously there’s logging, but it seems at some point you might require SSHing into the actual machine of interest and checking around. If this is the case, it seems you would need to open up port 22 on every machine in the network. To make it secure, I would only allow bastion host to connect to my IP address, and then every other machine only allows connections from the bastion host on the internal network. Is this considered bad practice? If so, what is the right way to go about this situation?

## Is there any decentralized, “serverless” network of any kind in existence with more than a handful of users?

I’m trying to verify that the findings of my own private "research", spanning over 10 years are accurate.

Basically, I’ve been actively hunting for any signs of any kind of "Internet alternative", decentralized network running "inside" the Internet, or even just individual applications for a specific task, which have more than a nominal group of hardcore fans who don’t actually use it meaningfully because they are just to few.

I first attempted to make a list of all the services I’ve already concluded are dead or won’t ever get ready, but I soon gave up and removed that part from the post. Whether I have such a list or not, I know that there will be tongue-in-cheek suggestions such as "Tor" or "Freenet" or "Zeronet", but please try to take this seriously.

I have so many times got excited (Dat, SAFE Network, IPFS, etc.) only to fall back into my chair, depressed from the total lack of activity inside each network. It’s not meaningful to sit and create things that nobody will ever be able to access, and which stands an even lesser chance of being profitable.

(No, I’m not greedy, but I need to make money somehow in order to survive and the old Internet has been utterly destroyed in every way. However, I’m not going to elaborate on that since, if you don’t already agree with me at this point, there isn’t really anything I can ever say to convince you otherwise.)

My sad conclusion is that there just is no such network/protocol/service as I’m looking for. Nobody has managed to market their solution in any meaningful way, perpetually working on code while ignoring the world which has never heard of their fantastic thing which is just a directory tree on GitHub, year after year…

The only non-fake, semi-useful individual applications I’ve been able to find are Bitcoin Core and Bisq. However, neither of those help me reach out to people or communicate in any way. The first is just a "digital wallet" and the second enables me to buy Bitcoin for fiat money via bank transfers with individuals without having to send in a photo id to some centralized site (which is one of the reasons why the old Internet is destroyed).

So, could it actually be that, in spite of actively searching everywhere for this, I’ve somehow missed something which is huge and decentralized? Another huge problem is that there’s a million sites/projects/whitepapers which lie about being dencentralized/privacy-respecting/secure, which further complicates things. I’ve seen countless websites which appear to have been mass produced just to "muddle the waters".

I’m looking for some way to reach out to people and not be harassed with "phone verification" or "sorry, we cannot grant access at this time" fake error messages for VPN/Tor users. "SAFE Network" has been working for over a decade and are forever and always "just a few months away" from release…

PS: Please don’t reply something about how "the Internet is already decentralized". No. It isn’t. It’s the most centralized network imaginable in its current form.

## Security camera NVR is making my network not PCI compliant. What can I do?

So family operates a small bar/lounge in Florida and I work for them part time as a bar back / IT technician. For the past couple months we have been trying to become pci compliant. However, we keep running into issues with passing a network vulnerability scan (which I think is being caused by our icrealtime security camera nvr.

We use clover stations for are 3 pos/terminal systems and are, according to cloversecurity, SAQ type C.

The vulnerability report is as follows:

General remote services - SSL Certificate - Signature Verification Failed Vulnerability httpsport / tcp over ssl  CGI - HTTP Security Header Not Detected httpsport / tcp  General remote services - SSL Certificate - Invalid Maximum Validity Date Detected - httpsport / tcp over ssl General remote services - SSL/TLS Server supports TLSv1.0 - httpsport / tcp over ssl 

This is how I have the network set up: Spectrum modem – > Edgerouter X

On the ERX all 4 ethernet ports are separated (e.g. .1.x , .2.x, .3.x , .4.x).

The .1.x has our jukebox and ATM machine. The .2.x has our IoT (atm only security camera) The .3.x and .4.x contain our pos on one and employee and guest wifi (on a r500 AC point) 

I have a firewall ruleset allowing only related/established access to the security camera but blocking IoT network from accessing other lans. I am also dropping connections to the http and https ports for the security camera network but the scan still fails.

I can disable https on the box but can’t disable the http and when I do that I still get an error for:

HTTP Security Header Not Detected httpport / tcp  

I’m not sure what else I can do? AFAIK its only the remote gui/webserver of the security camera nvr causing the issues. additional information: I should have a working security certificate from letsencrypt on the ERX so as I don’t get a warning when accessing the gui on my local network (router gui can’t be accessed outside network and POS network and guest network are blocked from accessing that gui)