I'm planning my first network with 2 subnets and came up with the following schema:    I'd like to know...   Would this work? Did I use the right amount of routers? Did I configure everything correctly? Plus, do I need to configure static routing here, so that every host within the subnets has internet access?
This is a  about IPv4 Subnets.      Related:               How does Subnetting Work, and How do you do it by hand or in your head?  Can someone explain both conceptually and with several examples? Server Fault gets lots of subnetting homework questions, so we could use an answer to point them to on Server Fault itself.   If I have a network, how do I figure out how to split it up? If I am given a netmask, how do I know what the network Range is for it? Sometimes there is a slash followed by a number, what is that number? Sometimes there is a subnet mask, but also a wildcard mask, they seem like the same thing but they are different? Someone mentioned something about knowing binary for this?
The final state of 1000 light bulbs switched on/off by 1000 people passing by There are  1000  light bulbs and 1000 tutors. All light bulbs are off. Tutor 1 goes flipping light bulb 1,2,3,4... tutor 2 then flips 2,4,6,8... tutor 3 then 3,6,9...etc until all 1000 tutors have done this.  What is the status of light bulb 25? 93? 576?  Is there a general solution to find out the status of any light bulb?  How many light bulbs are on after all 1000 tutors have gone by?  Not homework but a UK university interview question. Please help. Is there a way to view the site without having to look at reputation information? I do not want to track my rep information or see anyone else's.  I think that'll let me focus more on the questions themselves.  Is anyone else interested in this feature? I don't see anything on Stack Overflow itself, but are there any add-ins or  scripts that do this? Forbid links to open new tabs in Google Chrome So the complex number z is given as   $z=1-cos(2\theta)-isin(2\theta)$  And the question is to find the argument of z in terms of $\theta$.   So, I used the formula for calculating the argument of a complex number:  $arg(z)=arctan (\frac{sin(2\theta)}{1-cos(2\theta)})$  $=arctan (\frac{2sin\theta cos\theta}{1-(1-2sin^2\theta)})$  $=arctan (\frac{2sin\theta cos\theta}{2sin^2\theta})$  $=arctan (\frac{cos\theta}{sin\theta})$  $=arctan (cot\theta)$  $=arctan (tan(\frac{\pi}{2}-\theta))$  $=\frac{\pi}{2}-\theta$  But apparently the answer is $\theta-\frac{\pi}{2}$.  Where might have I gone wrong?  Edit: the domain given in the question for $\theta$ was $0≤\theta≤\pi$ REML or ML to compare two mixed effects models with differing fixed effects, but with the same random effect? Background:  Note: My data set and R code are included below text I wish to use AIC to compare two mixed effects models generated using the lme4 package in R.  Each model has one fixed effect and one random effect.  The fixed effect differs between models, but the random effect remains the same between models.  I've found that if I use REML=TRUE, model2 has the lower AIC score, but if I use REML=FALSE, model1 has the lower AIC score. Support for using ML: Zuur et al. (2009; p. 122) suggest that &quot;To compare models with nested fixed effects (but with the same random structure), ML estimation must be used and not REML.&quot;  This indicates to me that I ought to use ML since my random effects are the same in both models, but my fixed effects differ.  [Zuur et al. 2009.  Mixed Effect Models and Extensions in Ecology with R.  Springer.] Support for using REML: However, I notice that when I use ML, the residual variance associated with the random effects differs between the two models (model1 = 136.3; model2 = 112.9), but when I use REML, it is the same between models (model1=model2=151.5).  This implies to me that I ought instead to use REML so that the random residual variance remains the same between models with the same random variable. Question: Doesn't it make more sense to use REML than ML for comparisons of models where the fixed effects change and the random effects remain the same?  If not, can you explain why or point me to other literature that explains more? # Model2 &quot;wins&quot; if REML=TRUE: REMLmodel1 = lmer(Response ~ Fixed1 + (1|Random1),data,REML = TRUE) REMLmodel2 = lmer(Response ~ Fixed2 + (1|Random1),data,REML = TRUE) AIC(REMLmodel1,REMLmodel2) summary(REMLmodel1) summary(REMLmodel2)  # Model1 &quot;wins&quot; if REML=FALSE: MLmodel1 = lmer(Response ~ Fixed1 + (1|Random1),data,REML = FALSE) MLmodel2 = lmer(Response ~ Fixed2 + (1|Random1),data,REML = FALSE) AIC(MLmodel1,MLmodel2) summary(MLmodel1) summary(MLmodel2)  Dataset: Response    Fixed1  Fixed2  Random1 5.20    A   A   1 32.50   A   A   1 6.57    A   A   2 24.77   A   B   3 41.69   A   B   3 34.29   A   B   4 1.80    A   B   4 10.00   A   B   5 15.56   A   B   5 4.44    A   C   6 21.65   A   C   6 9.20    A   C   7 4.11    A   C   7 12.52   B   D   8 0.25    B   D   8 27.34   B   D   9 11.54   B   E   10 0.86    B   E   10 0.68    B   E   11 4.00    B   E   11 Comparing mixed-effects and fixed-effects models (testing significance of random effects) Given three variables, y and x, which are positive continuous, and z, which is categorical, I have two candidate models given by:  fit.me &lt;- lmer( y ~ 1 + x + ( 1 + x | factor(z) ) )   and  fit.fe &lt;- lm( y ~ 1 + x )   I hope to compare these models to determine which model is more appropriate. It seems to me that in some sense fit.fe is nested within fit.me. Typically, when this general scenario holds, a chi-squared test can be performed. In R, we can perform this test with the following command,  anova(fit.fe,fit.me)   When both models contain random-effects (generated by lmer from the lme4 package), the anova() command works fine. Owing to boundary parameters, it is normally advisable to test the resulting Chi-Square statistic via simulation, nonetheless, we can still use the statistic in the simulation procedure.  When both models contain only fixed-effects, this approach---and, the associated anova() command---work fine.  However, when one model contains random effects and the reduced model contains only fixed-effects, as in the above scenario, the anova() command doesn't work.  More specifically, I get the following error:   &gt; anova(fit.fe, fit.me)  Error: $ operator not defined for this S4 class   Is there anything wrong with using the Chi-Square approach from above (with simulation)? Or is this simply a problem of anova() not knowing how to deal with linear models generated by different functions?  In other words, would it be appropriate to manually generate the Chi-Square statistic derived from the models? If so, what are the appropriate degrees of freedom for comparing these models? By my reckoning:  $$ F = \frac{\left((SSE_{reduced}-SSE_{full})/(p-k)\right)}{\left((SSE_{full})/(n-p-1)\right)} \sim F_{p-k,n-p-1} $$  We are estimating two parameters in the fixed effects model (slope and intercept) and two more parameters (variance parameters for the random slope and random intercept) in the mixed-effects model. Typically, the intercept parameter isn't counted in the degrees of freedom computation, so that implies that $k=1$ and $p=k+2=3$; having said that I'm not sure if the variance parameters for the random-effects parameters should be included in the degrees of freedom computation; the variance estimates for fixed-effect parameters are not considered, but I believe that to be because the parameter estimates for fixed effects are assumed to be unknown constants whilst they are considered to be unknowable random variables for mixed effects. I would appreciate some assistance on this issue.  Finally, does anybody have a more appropriate (R-based) solution to comparing these models? A 'for' loop to iterate over an enum in Java What do you call someone who always puts blame on others? Does the rotation of the earth dramatically affect airplane flight time? Say I'm flying from Sydney, to Los Angeles (S2LA), back to Sydney (LA2S).  During S2LA, travelling with the rotation of the earth, would the flight time be longer than LA2S on account of Los Angeles turning/moving away from our position?  Or, in the opposite direction, would the flight to Sydney be faster since the Earth turns underneath us and moves Sydney closer?  ===   Please ignore jet stream effects and all other variables; this is a control case in an ideal environment. By "dramatically" I suppose I mean a delay of 1 hour or more. Survival probability up to time $n$ in a branching process. Let $\{Z_n : n=0,1,2,\ldots\}$ be a Galton-Watson branching process with time-homogeneous offspring distribution $$\mathbb P(Z_{n,j} = 0) = 1-p = 1 - \mathbb P(Z_{n,j}=2), $$ where $0&lt;p&lt;1$. That is, $Z_0 = 1$ and $$Z_n = \sum_{j=1}^{Z_{n-1}}Z_{n,j}$$ for $n\geqslant 1$. Let  $$T=\inf\{n : Z_n=0\} $$ be the extinction time of the process. I want to find $$t_n := \mathbb P(T&gt;n), $$ i.e. the probability that the process survives up to time $n$. I found the following recurrence:  $$t_{n+1} = p(2t_n - t_n^2)$$ (with $t_0=1$) from this mathoverflow question:   I checked the recurrence for small values of $n$, and confirmed that $t:=\lim_{n\to\infty} t_n$ satisfies $$ t = p(2t - t^2),$$ both in the case where $t=0$ $\left(p\leqslant\frac12\right)$ and where $t=2-\frac1p$ $\left(p&gt;\frac12\right)$. So I'm fairly confident this recurrence is valid. However, I have no idea how to solve it.  For context, this problem comes from Adventures in Stochastic Processes by Sidney Resnick:   From @Did's comment, it appears to be intractable to find a closed form for $\mathbb P(T&gt;n)$. I find it curious that the question would be asked were it not, though. After writing the FreeNAS IMG to a 16 GB USB flash drive, I can now only use 938 MB. I used the Win32 Disk Imager tool to write the IMG to the device. Then later, when I inserted the the USB drive into my Windows 7 computer it said that it had to be formatted, because it couldn't read it. I believe this is normal. So I formatted it inside Windows using the format option when prompted. So in Windows Explorer now, 938 MB is reported as capacity of this device.    Also, when i check the properties dialog box I can see the same numbers.    And when I check with diskmgmt.msc I can see there are several volumes I don't recognize and unallocated space of 12.79 GB.    Now, I have another 2 GB USB flash drive with the same problem. It too was used for FreeNAS, and it too has a reported capacity of only 938 MB. I thought it was broken there for a while, until I saw the same problem with this 16 GB model.  I tried using diskpart on the 2 GB model, and I saw that there were several partitions there (list partitions) just like on this one. So I used the clean option to try to wipe it, but that wiped off everything so it's totally useless now. I'm not sure how to rebuild it.  Is this a standard routine, like part of the whole "user experience", that whenever you make a bootable USB falsh drive with FreeNAS, it messes up your device? I am new to FreeNAS, so i wouldn't know. But it sure looks like it. Maybe it is in fact the format operation in Windows that messes things up... I don't know. It's not very nice.  How do I restore the capacity back to 16 GB-ish (14.9 GiB)? How to echo output of a top into a text file? I want to write batch or something, that will write output of top into a file on login.  I did top &gt;&gt; output-file, but it contains some strange character!  Can somebody give a simple tutorial about how to write batch file in Linux? Managing multiple asynchronous NSURLConnection connections GIS Point or discrete longitude and latitude columns? Getting tabular statistics from table using QGIS? Are there QGIS tools that will allow users to get tabular statistics from their table?  I kind of expected I would be able to just open the table, select the field I was interested in, right-click on the field header and get something similar to this (screenshot taken from ArcGIS):    More specifically, I am looking for a QGIS alternative to the ArcGIS  and  tools, that offer a  you can retrieve about the tabular data.    Just after asking, I found  (see section 4.2 ) that describes how to find this functionality... Vector > Analysis Tools > Basic statistics.  I also found Vector > Analysis Tools > List Unique Values right next to it.  This gets me the list of unique values, but I would also like to see an additional column of frequency (count) of each unique item.  Is this similar tool available "out-of-the-box"? How to make the taskbar blink my application like Messenger does when a new message arrive? Is there an API call in .NET or a native DLL that I can use to create similar behaviour as Windows Live Messenger when a response comes from someone I chat with? Why must a final variable be initialized before constructor completes? For some or other reason, typing @ᔕᖺᘎᕊ in a chat room pings everyone who's been in that chat room for the last 7 days...    Seems to work in all chat rooms (I only tested 2 as I don't want to upset too many people...)  How should we proceed? How do I add a Pokestop to an area that has none? It is an area where there are tons of businesses but unless I drive about a mile from my work area there are no Pokestops.   I want to add one since we have 1000's of people in the work area, a lot of them play Pokemon Go, and we all can't leave work to drive a mile away to get to a Pokestop area.   Plus it would be nice to be able to capture Pokemon on our breaks. We login to applications almost every day. The password is stored in our fingers, as an automated process (if they have used it long enough). When users realize they have entered a wrong character (before hitting login-button) they erase the whole password, and retype the entire password – instead of just the last wrong character. Question is why?         &ndash; Wireframes created with