For chicken-and-egg apps which require a network effect, should I try to delay my user from noticing early on that there aren’t many others?

For example, in my user registration, I can let the user pick preferences for other users, similar to a dating app.

If those other users get filtered out, this introduces the possibility for the user’s first impression using the app to be, “Oh, there’s nobody here. Is this thing dead?” -> close -> uninstall -> and they’ll probably never come back. Churn. Actually, it’s just brand new!

So while I’m growing the app and there’s not many on it yet, should I leave those preferences out of the registration, just so their first impression isn’t that the app is dead, and slightly delay it, allowing them to choose the preferences later? They could still potentially get value from the app if it’s not just their strict preferences right away.

I know there’s not too much I can do here, but what is your recommendation?

System of delay differential equations: using first interpolation as second initial condition

I am trying to solve numerically the following system of two coupled delay differential equations:

$ $ \dot x(t)=-\gamma x(t)-\frac{\gamma}{4}e^{i\omega_0\tau_1}y(t-\tau_1)\theta(t-\tau_1)+\frac{\gamma}{4}e^{i\omega_0\tau_2}y(t-\tau_2)\theta(t-\tau_2)+\frac{\gamma}{2}e^{i\omega_0\tau_3}x(t-\tau_3)\theta(t-\tau_3),$ $ $ $ \dot y(t)= -\frac{\gamma}{2}y(t)-\frac{\gamma}{4}e^{i\omega_0\tau_1}x(t-\tau_1)\theta(t-\tau_1)+\frac{\gamma}{4}e^{i\omega_0\tau_2}x(t-\tau_2)\theta(t-\tau_2).$ $ where $ \tau_1<\tau_2<\tau_3$ . The parameters $ \gamma, \omega_0$ are constants, and $ \theta(t)$ is the Heaviside step function. The history of the system is known for $ 0\leq t\leq\tau_1$ : $ $ x(t)=e^{-\gamma t}, y(t)=e^{-\gamma t/2}.$ $ Here what I tried:

I first solved the system for $ 0\leq t\leq\tau_2$ using the aforementioned initial history using NDSolve:

\[Gamma] = 1.0; \[Omega]0 = 2 Pi; \[Tau]1 = 1.0; \[Tau]2 = 2.0; \[Tau]3 = 3.0;  sol1 = NDSolve[{x'[   t] == - \[Gamma] x[t] - (\[Gamma]/4) E^(I \[Tau]1 \[Omega]0)     y[t - \[Tau]1],  y'[t] == - 0.5 \[Gamma] y[t] - (\[Gamma]/4) E^(    I \[Tau]1 \[Omega]0) x[t - \[Tau]1],  x[t /; t <= \[Tau]1] == (1.0/Sqrt[2.0]) Exp[-\[Gamma] t],  y[t /; t <= \[Tau]1] == (1.0/Sqrt[2.0]) Exp[-0.5 \[Gamma] t]}, {x,  y}, {t, 0, \[Tau]2}]; 

I get the following solution for $ |x(t)|^2$ and $ |y(t)|^2$ : abs[x]^2,abs[y]^2

The problem arises when I use this first interpolated solution as the initial history to solve for the next interval of time:

sol2 = NDSolve[{x'[   t] == - \[Gamma] x[t] - (\[Gamma]/4) E^(I \[Tau]1 \[Omega]0)     y[t - \[Tau]1] + (\[Gamma]/4) E^(I \[Tau]2 \[Omega]0)     y[t - \[Tau]2],  y'[t] == - 0.5 \[Gamma] y[t] - (\[Gamma]/4) E^(    I \[Tau]1 \[Omega]0) x[t - \[Tau]1] + (\[Gamma]/4) E^(    I \[Tau]2 \[Omega]0) x[t - \[Tau]2],  x[t /; t <= \[Tau]2] == Evaluate[x[t] /. sol1],  y[t /; t <= \[Tau]2] == Evaluate[y[t] /. sol1]}, {x, y}, {t,  0, \[Tau]3}];  

This time I get the following messages: enter image description here enter image description here

It seems that the second NDSolve (sol2) does not allow the interpolation of the first result as initial history. Any suggestion? Thank you in advance.

Whenever a project is edited, it causes all articles file to be rewritten and causes huge delay

I have imported many articles. They are 270mb

I just noticed that whenever I edit a project, all articles file is rewritten even though I didn’t make a single change

I suppose they are also read whenever we click edit of any project thus taking really long time to load the project edit window 

This causes huge delay. Can you make articles read and write only whenever we make change of an article?

Should I keep the default tap delay?

Since I read 300ms tap delay, gone away I always figured it was a good thing.

Now a colleague recenctly told me they was against this because as it is the default behavior it is “accessibility” to keep it.

They also didn’t see any problem with the delay and that they liked the double-tap zoom.

Now I never considered things that way so are there some studies which could back one claim or another?

Delay loading images

I’m trying to improve page loads by following the steps outlined on this page but it is not working.

Here’s what I did

  1. Created a delayLoadImages.js file
  2. Added link to the js file on my home.html
  3. Inserted home.html path to a web part.

delayLoadImages.js file

//Keep the ribbon at the top of the page $  ('#s4-workspace').on("scroll", function () {     loadItemsInView(); });  function loadItemsInView() {   //Select elements by the row id.   $  ("#row [data-src]").each(function () {       var isVisible = isElementInViewport(this);       if (isVisible) {           if ($  (this).attr("src") == undefined) {               $  (this).attr("src", $  (this).data("src"));           }       }   }); }  function isElementInViewport(el) {   if (!el)     return false;   var rect = el.getBoundingClientRect();   return ( >= 0 && rect.left >= 0 && rect.bottom <= (window.innerHeight || document.documentElement.clientHeight) && rect.right <= (window.innerWidth || document.documentElement.clientWidth)    ); }   

HTML – link within <head>

  <script src="/sites/xxxx/SiteAssets/js/delayLoadImages.js"></script> 

REST API – I’m using REST to pull the data from a list.

chlList = chlList + '<div class="carousel-item active">'  + '<div class="col-12 col-sm-6 col-md-4 col-lg-3"><div class="card mb-2">' + '<img class="card-img-top" src="" data-src="' + chlImageUrl + '" alt="' + chlTitle + '" title="' + chlTitle + '" />' + '<div class="cardNumber">' + cardNumber + '</div>' + '<div class="card-body card-body-chl parentWidth"><div class="cardPosted">' + chlPosted + '</div><div class="card-text block-ellipsis">' + chlTitle + '</div>' + '<button class="btn btn-warning" type="button">' + 'Details</button></div>' + '</div></div></div>'; 

Working code before adding the data-src

chlList = chlList + '<div class="carousel-item active">'  + '<div class="col-12 col-sm-6 col-md-4 col-lg-3"><div class="card mb-2">' + '<img class="card-img-top" src="' + chlImageUrl + '" alt="' + chlTitle + '" title="' + chlTitle + '">' + '<div class="card-body parentWidth"><div class="card-text block-ellipsis">' + chlTitle + '</div>' + '<button class="btn btn-primary" type="button">' + 'View More</button></div>' + '</div></div></div>'; 


  • Delay loading images and JavaScript in SharePoint Online

Fix audio delay of -0,5 seconds in movie

I can edit my movie in some video editor and perfectly match audio with video, but in that case I would have to re-encode the entire video which would be time consuming. Code like:

ffmpeg -i my_movie.mp4 -c:v copy -c:a aac -af "audio_filter_help_me_guys" fixed_movie.mp4 

would save my time. Or I just have to use video editor such as Kdenlive?

How to send packets at 512 nano sec delay using Socket Programming and UDP socket

Using SOCK_DGRAM for UDP sockets

All packets are 22 bytes in length (ie 64 including headers)


...     no_of_packets--;     sprintf(buf, "#:!0 rem");     sprintf(buf, format , buf);     sprintf(buf_aux, "#: 0 rem");     sprintf(buf_aux, format , buf_aux);     buf[MAX_LINE-1] = '';     buf_aux[MAX_LINE-1] = '';     len = strlen(buf) + 1;     send(s, buf, len, 0);     while (no_of_packets-- > 1) {         nanosleep(&T, NULL);         send(s, buf, len, 0);     }     send(s, buf_aux, len, 0); 


... while(1) {         if (len = recv(s, buf, sizeof(buf), 0)){             // do nothing         } }  

When I open Wireshark to see avg delay between the packets which are sent,

I can see the following:

  • MIN delay: 0.000 006 795 sec => 6 micro sec

  • MAX delay: 0.000 260 952 sec => 260 micro sec

  • But I want to send packets every 512 nano sec (ie., 0.512 micro sec).

How can I achieve this speed?