Yeah, so in yesterday's class we looked at box functions right and we saw that we could use a whole set of box functions to represent any given function right. I was originally planning to do hat functions today but first maybe we will look at polynomials and functions as means of generating basis vectors say on a given interval right and see what is the problem with that and then we will go on to hat function is that fine. So the question is the problem that we had with the box function was that even for a straight line if you wanted to approximate the straight line we got because our function is a constant on a given interval. We got a representation which was piecewise constant right and we could get as close as we want to the function that we are trying to represent but then as a consequence the jumps that we get the number of jumps that we get in the function representation increases right. So we are trying to ask the question is not there a way for us to get something that is smoother. We have defined the dot product yesterday as the dot product of f, g as the integral if the functions are defined on the interval a, b as fg dx. We will see what this means if we just take an interval again say 01 or something of that sort and what it means to the standard polynomials that we deal with okay and see whether we can use those to represent our functions. So consider the functions two functions f of x equals 1 and g of x equals x to start with are these functions orthogonal to each other or what is the angle between these functions does that make sense. So once you have defined the dot product we can use the definition of the dot product that we had earlier from geometry where we said that a dot b is magnitude a magnitude b cosine of the angle included angle between them you can use a similar idea and basically say that cosine of the angle between two functions would be the dot product fg divided by the norm of f norm of g right analogous to what we did with vectors you could define a theta in a similar fashion. So the question that I am asking so we have already used actually we have already used the property that theta is pi by 2 is that the two functions are orthogonal we have already done that yesterday. Question that I am asking is it possible for us to find the angle between the functions f and g as given there okay. So what is f dot g what is that dot product integral x let us say the functions are defined on the interval x belongs to the interval 0, 1 let us say we take x from on the interval 0, 1 the function is defined on the interval 0, 1. So it is 1 times x dx which gives me x squared by 2 between the limit 0, 1 which is one half that fine. So clearly they are not orthogonal clearly they are not orthogonal what is magnitude f magnitude f is the square root of integral 0 to 1 dx which is 1 and what is magnitude g the norm of g integral 0 to 1 x squared dx square root which gives me x cube by 3 between 0 to 1, 1 divided by square root of 3 is that fine okay. And therefore of course all of these numbers look familiar because we just dealt with something very similar in the last class and therefore what do we get for cos theta 1 by 2 root 3 and you can consequently find theta. So it is just an interesting exercise you can consequently find theta what does it mean on which side is there a mistake root 3 by did I goof I made a mistake oh I am sorry I root 3 by 2 I am sorry root 3 by 2 it gives a much better number right gives you a much better angle okay right. So but I am not really interested in finding theta here right or I realize that theta is not pi by 2 okay and we have already seen earlier that it is very convenient to have these functions or the basis vectors that we get to be orthogonal to each other right we have already seen that it is convenient to have these vectors orthogonal to each other. So given this we will follow the same process that we did earlier and try to get 2 sets of vectors 2 vectors which are perpendicular to each other from the 1, x so 1, x are linearly independent 1 and x are linearly independent how do I find how do I get 2 vectors so that that angle is pi by 2. So what I do is I repeat what we did earlier so if this is a and this is b right so from a of course I can get the unit vector a little a which is a hat right and I can find the projection of b on a how do I find the projection of b on a I take b dot a okay. So b dot a gives me the projection the component of b that is along a right b dot a gives me a component of b that is along a let me just give it a subscript b sub a b sub a times a hat what is that that is a vector representation of the component of b along a right.  So now the question is what is b prime dot a b prime dot a is 0 so we have managed to construct we have managed to construct the b prime which is orthogonal to a and from b prime from b prime I can get a I will just call it a b hat by dividing by the magnitude of b prime okay. So you gave me a b to start with and I come back with an a prime b prime I am sorry a hat b hat which are unit vectors which are orthogonal to each other okay so you have given me one set of vectors I have now managed to extract from that a hat b hat which are orthogonal to each other. So if I had a third function if I had a third vector c I could repeat this process if I had a third vector c what I would basically do is from the third vector I will subtract out the b hat part I will subtract out the a hat part and I will be left with something that is purely c right if I am left with nothing that means c was linearly dependent on the other two is that fine okay. We will do that now to the functions we will do that now to the vectors 1 and x so back here we asked the question what was f dot g, f dot g was 1 half so this is this times 1 so the function that is along that is the component of f that is along g or g that is along f is 1 half it is g along f right and f is a constant and therefore if I subtract out if I repeat the process b minus b prime a b minus b dot a if I repeat the feed that process what I am going to get is I am going to get x minus 1 half times 1 the basis vector is just the constant function 1 okay and this should be now my new improved this should be now my new improved g prime is that fine okay. So can I make this a unit vector is it possible for me to make it a unit vector g prime how do I make g prime the unit vector so what is g prime dotted with g prime x minus 1 half squared dx on the interval on which it is defined which is x minus half cubed between 0 and 1 and what is this 1 half cubed plus 1 half cubed I am sorry which equals 1 4 to z right into oh I am sorry x by 3 by 3 fine okay and therefore g hat g if you want to call it g prime hat if you want to call put a hat on it just like we did for the other unit vector or I just call it g hat g hat would be x minus 1 half I have to divide by the magnitude in the magnitude is 2 times square root 3 are there any questions it is fine. So now we have the vectors 1 2 times square root 3 into x minus 1 half is that fine these are orthonormal magnitudes are 1 and they are orthogonal to each other okay let me add a third vector into the mix what if I added x squared I want to add x squared so I define an h of x which is x squared if I define an h of x which is x squared and this is still on the interval 0 1 if I define an h of x which is x squared what is g hat dotted with h that is 2 root 3 x minus 1 half into x squared integral from 0 to 1 dx is that fine yeah so what does this integral give me this gives me a 2 root 3 into that gives me a x to the 4th divided by 4 minus x cube divided by 6 between the limits 0 and 1 which is 2 root 3 times 1 fourth minus 1 sixth what does that give me 1 by 2 root 3 so that is the component of h along g hat so we repeat this process so from h that is x squared I subtract out this component so that is 1 over 2 root 3 times what is the basis vector 2 root 3 into x minus half I am repeating the same process that I did here b minus ba times a I am repeating the same process that I did there which of course gives me x squared minus x plus half and there is something wrong we have to okay that is fine so what is the other thing that we have that is x squared minus x plus half yeah that is fine so what do we have now so we have removed the g hat component this is has removed the g hat component so what I will call this is h hat h prime now I want from this I want to get rid of the component that belongs to 1 the function 1 so what is h prime dot f that is integral 0 to 1 x squared minus x plus 1 half times dx which gives me x cube by 3 minus x squared by 2 plus x by 2 between the limits 0 and 1 and that should give me the projection of h prime on f which is nothing but 1 by 3 minus 1 by 2 plus 1 by 2 which is 1 third that is fine and as a consequence if I subtract this out from here I am going to get h double prime which is x squared minus x plus 1 6 minus x plus 1 6 okay if I subtract a third from the half I get 1 6 and I will let you verify you can verify that h hat in fact is 6 times 5th root of 5 x squared minus x plus 1 6 and just check that out find out what the magnitude is if I am taking the no I am taking you are saying do g instead of g prime and whether I take h prime there or h it does not matter you are saying why did not I just do x cube instead of x squared times 1 whatever that is fine yeah yeah the order does not matter the order does not matter what you have to basically do is you have to make sure that if you have a set of vectors that you are subtracting out this and this from x yeah that is true you could what you are basically saying then the expression is a lot easier I did not I did not have to include that x plus half because anyway it is orthogonal that is true yeah yeah because the part that I am subtracting out you understand the point that he is making the part that I have subtracted out here it basically comes from is already orthogonal to f so there is no reason to include that in the calculation is that fine okay yeah are there any questions so you can see you can see that excuse me you can see that now I have I will call them f hat g hat h hat you can see that I can actually generate a whole function a whole set of these functions okay in fact I can just take I can take the set 1 x x squared x cube x to the fourth and so on and I can I can generate a whole set of these basis vectors that are orthonormal orthogonal to each other and the magnitude is 1 right based on our definition of the dot product is that fine okay now why do not we just use this why do not we just use this to represent our functions right why not just use this to represent our functions so that is one question that we have why bother with box functions these are nice and smooth functions why not just use these to represent our functions is that fine okay of course if our function had a cubic variation and we took only the first term first three terms right we are unlikely to pick up that cubic variation properly am I making sense you can see what you can go check to see what kind of an error that you would make and so on the other problem is just like in Fourier series maybe we look at Fourier series a little right now just I am not sure how many of you are familiar with Fourier series there is the issue of how do we when we have when we are hunting remember do not forget why we are doing this why we are why we are constructing these orthonormal functions right just to recollect our governing equations or differential equations the solutions are functions we want to write programs that will systematically hunt for the solution which means systematically hunt for the functions so we are trying to create a set of functions which have some structure in them so that we can search them in a systematic fashion okay so such a set of functions right such a set of functions which have this nice structure what is the distance between functions and so on such a set of functions we will call it a space a function space a space of functions right and we are basically trying to construct a function space that is essentially it okay so let us let let let us see let us see what happens let me we will get by maybe what we will do is we will do Fourier series also we will go along and then see what is the issue with what is the issue why can't we why do not we use this right and we do use it sometimes let us let us see what we get now one of the points that I want you to check out you can try this out now if I take the same functions 1 x x squared and so on I take the same set of functions but now they are defined on the interval minus 1 to 1 does anything change does anything change so what happens to f.g becomes minus 1 to 1 1 times x dx is x squared by 2 from minus 1 to plus 1 and it is 0 they are orthogonal so the orthogonality depends on the interval in which the function is defined the dot product is defined over that whole interval it may be obvious right when you look at it but the number of times students make a generic statement sign sign and cosine or orthogonal to each other and then integrate on the wrong interval right it happens it happens to all of us right so you have to be a bit careful it is orthogonal from minus 1 to plus 1 but not orthogonal on the interval 0 to 1 okay I would suggest that you try to do a few of these on the interval minus 1 to plus 1 just like I I have gone through right so for on the interval 0 1 I would suggest that you try x cubed or something of that sort just to make sure that you are able to get through on that and then do these from minus 1 to plus 1 do a few of them okay and if you have had ordinary differential equations if you had a course in ordinary differential equations before pay attention to the functions that you are getting and ask yourself have you seen them before right you should get a familiar set of functions right especially if you have done a course in ordinary differential equations this interval minus 1 to plus 1 should give you should yield a familiar set of functions right let us look at I am not going to do Fourier series in great detail here so Fourier series the functions that you are looking at are of the form 1 sin cosine sin 2 cosine 2 and so on they are functions of this nature okay so the obvious question from this discussion the obvious question is is are the functions 1 and sin orthogonal to each other right so now you should always remember you have to ask the question on what interval are we talking right what is the dot product definition the dot product and what is the interval on which we are talking so if you say that on the interval 0 to 1 sin of x dx not 0 right on the other hand if you take say on the interval 0 to 2 pi sin of x dx you do get 0 fine so the functions 1 and sin are indeed orthogonal are indeed orthogonal on the on that interval and of course you can figure out how to go about normalizing it and so on so the point of this discussion is that the interval the domain on which we are we are defining the function is important right for our for our idea of orthogonality just as it is important for our idea of the dot product and of course when we are actually solving problems when we get to the point where we are actually solving working on fluid mechanics problems and asking questions and answering questions and fluid mechanics you will have you will know what is the extent of your domain and therefore you will know what are a and b fine so why don't we just use this why don't we just use 1x x squared and so on why not just use Fourier series right to fit so if I give you a function if I give you a graph if I give you some arbitrary graph why not just use these polynomials in order to approximate this function to represent this function why did I why do I go through this headache of trying to find piecewise constants that will approximate the function okay the idea here is that if I have if I have my f hat g hat h hat that I got earlier that I got here if I have the f hat g hat a hat I can try to find a f hat plus b g hat plus c h hat I can try to find the coefficients a b and c in order to approximate this function and then adjusting adjusting these values while I am hunting for the function any change I make to a will translate the whole graph up down any change I make to b will cause the slope to change any change I make to c right will cause the curvature to change everywhere keyword is everywhere right so if I am if I am now if I have this complicated function and I am trying to fit a curve to it every time I adjust one coefficient every time I adjust one coefficient to fit some part the trouble is it is going to get spoiled somewhere else very likely that it will change somewhere else I do not have what is called the property of locality I do not have this power where local changes local changes in coefficients cause only local changes in the function I want to be able to I want to be able to raise and lower this whereas if you take this box function it is possible for me to take this and lower it there independent of what is happening elsewhere I can just change the level of just at one interval right so the box function clearly has this property of locality I can just change in one interval I can change the level I can change the level of that function just in one interval without affecting anything else that is happening elsewhere okay. So this property of locality is very important this property of locality gives me this freedom gives me this freedom for me to adjust my solution as I go along okay without in particular without affecting other parts of my solution that I have already possibly adjusted to my satisfaction right whereas if I do not have locality if I do not have locality then a change any change that I make is a global change right so if I say a sin x if I change a sin x is going to change in fact if you think about it sin x actually defined from minus infinity to plus infinity so you are changing everything from minus infinity to plus infinity just by changing the same right total global change whereas what I would like to do is I would like to keep it local fine okay. So for that reason right now I am going to reject using f hat g hat h hat right having gone through this effort I basically say it is nice I know how to do it but I am going to reject this function okay we can come back later and see whether it is possible for us to use them or not what we would really like is we would like the smoothness that these polynomials bring and the locality that the box function got we would like to have the smoothness that these polynomials bring with tight to the locality that the box functions brought okay and therefore as a consequence now merging these two we are going to come up with hat functions we are going to define this as follows what we realize is if you have some from the yesterday's class we know if the support of two functions is non-overlapping is not overlapping then they will be orthogonal they are orthogonal to each other there is a reason why I repeat this there is a reason why I write this out and repeat this. So it has only to do with the support right remember the support basically means the function is non-zero in that part of the domain right so it has only to do with the support it does not actually have to do with the function value that means that if I have in yesterday I chose functions f and g in a fashion such that the support was non-overlapping this was f that was g and yesterday we basically said that f.g because the support is non-overlapping it turned out that f.g are orthogonal to each other the question is does it have to be a constant there it could be anything as long as it is not 0 right is that fine. So since this is true since it comes from the support what we will do is we will try to pick one of those polynomials to do it and to keep life easy we are going to pick the linear we are going to pick x right we are going to be a bit careful here so we pick x. So let me see if I can construct these functions in a systematic fashion so we have some interval a b that we are interested in right and as we did earlier we are going to break up this interval into sub-intervals I am going to look at focus on one particular sub-interval x i x i plus 1 okay so I will zoom in on that particular interval so what I am going to do is I am going to just zoom in on this particular interval that is x i x i plus 1 and I will define two functions here I will define two functions here one is a function it is basically 0 everywhere and at x i it is 0 and it then rises from x i to x i plus 1 it goes from 0 to the value 1 I will name this function n it is 1 at i plus 1 i plus 1 0 because I am going to define two such functions. The other function is also 0 everywhere right just like the box function the only difference is that it drops from 1 to 0 going from x i to x i plus 1 and since this function is 1 at x i I will call it n i and it is a second function so n i 1 is that fine do you understand what the functions do the blue one n i plus 1 0 is 0 everywhere so it is going to be 0 from a to b everywhere except on the interval x i x i plus 1 where it starts at 0 and in a linear fashion rises to 1 n i is again 0 everywhere over the whole interval a b except at x i x i plus 1 it starts at 1 goes down to 0 fine now clearly if I have two such functions clearly if I have two such functions on two different intervals if I have two such functions on two different intervals if I have one interval here and I have another interval here and if I have two such functions on these two different intervals I have one function here and at the same blue one function here one function there and one function here one function I have two such functions right this is n i plus 1 0 n i 1 this would be n j plus 1 0 n j 1 I have two such functions these two functions are orthogonal to those two functions each of these functions is orthogonal to each of those functions if I define such functions over all the intervals x i x i plus 1 in any given interval one of these functions will be orthogonal to functions in the other interval because intervals are non-overlapping fine so we use the fact that the supports are non-overlapping therefore they are orthogonal that is a good part but what about the two functions to each other the two functions obviously to each other are not orthogonal right they are obviously not orthogonal so what is that dot product what is n i 0 n i 1 I am sorry n i plus 1 dotted with is a function of x n i 0 is a function of x dx the integral it is 0 everywhere except from x i to x i plus 1 what is this function what is this integral so in order to do this we have to get a function form we have to get an algebraic form for n i and n i x okay I have to get an algebraic form for n i and n i n i plus 1 and n i plus 1 n i plus 1 x and n i x okay so we come back here what is n i plus 1 as a function of x x minus x i divided by x i plus 1 minus x i right there is a positive slope there is a positive slope over the length x x i x i plus 1 minus x i it goes from 0 to 1 right so at x equals x i it is 0 at x equals x i plus 1 it is 1 it is a linear function it satisfies it satisfies right again we are hunting even here if you think about it we are actually hunting for functions right I have given you a graph and we hunted and found that function okay and what is n i so if this is some alpha of x if this is some alpha of x I name it alpha of x simply because so what is n i 1 minus alpha of x are there any questions any questions fine so what we do is what we will do now is we will find out what is that what is the what is the dot product what is that dot product so n i 1 dotted with n i plus 1 0 gives me integral x i plus 1 to x i up x i to x i plus 1 alpha of x times 1 minus alpha of x dx what does this turn out to be you can just check that you can just verify that that is true so that fine okay so what do we have now what we have now is I have defined a bunch of functions n i 0 and n i plus 1 these depend of course on the interval so obviously if I go to i minus 1 if I go to i minus 1 this is on the interval i i plus 1 if I go to the interval i minus 1 to i what will I get corresponding functions n i minus 1 0 n i 1 am I making sense if I go to the intervals i minus 2 i minus 1 I will have the functions n i minus 2 0 n i minus 1 1 fine on each of the intervals I will have two of these functions what have we managed to do so far what can we do what can we do with these two functions that we have defined on the interval so first let us just focus on this interval alone we will just look at this interval alone so if I take a i a i or a times n i 1 plus b times n i plus 1 0 as some function f of x defined only on xi xi plus 1 what does this give me for any given a b what does the graph of this look like it has to be a straight line is the sum of two linear elements and if I were to graph it if I were to just graph f of x remember this is the interval xi xi plus 1 if I were to just graph it at x equals xi n i is 1 at x equals xi plus 1 n i plus 1 is 1 the other one is 0 so this is going to be a function that goes from a to b in a linear fashion so if I change my b value if I change the value of b if I were to raise the value of b from here to some value here then I would get a graph that looks like that right so I have a linear interpolant but I also have locality in the sense that if I raise this value a b it affects this interval and we will see if it affects anything else is that fine okay so a i a n i b n i plus 1 allows me to give you a get a linear interpolant in the interval xi xi plus 1 so in general if I had an arbitrary function f of x I should be able to write this f of x as summation i equals 1 through n I will just write it as 1 through n we have to figure out what happens at the intervals elsewhere towards the beginning and end anyway we will go through we have n n intervals i equals 1 through n what am I going to get a i n i 0 plus b i n i plus 1 1 is that fine the intervals are non-overlapping they are orthogonal it should be possible for me to represent any function f of x in this fashion on any given interval the a i b i will give me the straight line interpolant between those two points okay let us take two intervals and see what happens let us take two intervals and see what happens so this is xi minus 1 xi xi plus 1 okay so I have some function I have some function and I want to represent this function using my newly developed right linear interpolants so what I am going to do is I am going to use let me use some colored chalk here on the interval xi xi plus 1 if I take these two values to be a and b I will get a linear interpolant that looks like that on the interval xi minus 1 xi what will my a value be what is a a is the value here and what is b b is going to be what was the a and b xi xi plus 1 interval so in fact though it looks like though it looks like though it looks like I have two coefficient incidentally it is possible we could come up with a scheme just like in the box function if you are willing to allow discontinuities at this interval at the edge of this interval at the interface between the two if you are willing to allow discontinuities then a's and b's can be sub different but if you want the function to be a continuous function the representation to be a which is where we are going right now then the a i corresponding to xi right has to be the b i corresponding to the xi okay so the a and b at this point have to be the same is that okay everyone okay so in fact what you have to do is we have to recombine these so you are saying a i n i b i n i plus 1 so maybe what I should have done here was I should have made this b i plus 1 i plus 1 n i plus 1 okay if I make that b i plus 1 then what does that do for me then I can actually make the statement that a i should be equal to b i allows me to do that so the coefficient here is the same and what are the functions what are the basis vector what are the basis vectors n i n i is that it multiplies this coefficient a i what does it multiply it multiplies this is one or let me let me lower the let us just say this is one it multiplies this function what is this function what was this label n i 1 and it multiplies this function what was its label we have did I switch it around n i 0 n i 1 I have it right the first time around okay fine n i 0 yeah n i 1 I had it right the first time around okay there in the integral okay I made a mistake here okay that is fine yeah you guys should tell me immediately as soon as you catch it I have flipped it around everywhere thank you yeah you should not let me go through with this well fortunately what is going to happen is I am going to get rid of those superscripts okay fine look at the functions n i 0 and n i 1 n i 0 and n i 1 are non overlapping I can actually combine these 2 functions I can add them up I can literally add them up since a i and b i a i and b i are the same a i equals b i equals same this summation summation i equals 1 through n right since a i and b i are the same I have to just shift this so if I go back to when this was i – 1 i equals 1 or if you want me to I can write it out but anyway it is okay if I factor out the a i since the a i and b i are the same I am going to get what I have seen here is I am going to get an n i 0 plus an n i 1 that summation f of x you can open out the summation for a few terms and see that this is true okay it is actually possible for me to factor out the a i since a i equals b i it is actually possible for me to factor out the a for n i 0 and n i 1 these can be added these can actually add and if you add them this is the function that you get okay so this is summation i equals 1 through n a i n i I will rewrite this summation I will rewrite it at the other end. So f of x can in fact be written as summation i equals 1 through n a i n i where n i of x equals n i 0 of x plus n i 1 of x is that fine 0 to n – 1 as I said so we will have to look at what happens through because there is an issue so I leave these we will investigate I just write this just for right so we have to really look at what happens what happens for all these okay. So now for so the end points we look at what happens at the end points look at what happens at the end point you have to be a bit careful at the end okay right so what is this function n i what is the graph of the function n i so if I have x i I have x i – 1 I have x i plus 1 this is n i as a function of x it is 0 it is 0 from a to x i x i – 1 it rises it rises to 1 linearly drops to 0 at x i plus 1 linearly this again 0 okay and because of the shape of the function these functions are called either hat functions or tent functions you can imagine that if you construct functions like this in two dimensions that they look like a tent they are called tent functions or hat functions is that fine okay are there any questions okay so then we will continue with this in the next class.


Hello. Welcome to SSUnitex. So, see this side and this is continuation of PySpark interview questions and answers. So, in this video we are going to see how we can process the files those are received before or after specified time. It means we are going to specified on a time and we just want to process all those files which has been received before that specified time or after that specified time. So, while reading the data from the file we are required to check if that file is received before that time and if the file is is received after that time. So, inside the PySpark we are having these two options. First is the modified before and second is the modified after. So, when we can use the modified before and after. So, modified before this attribute can be used to read files that were modified before the specified time stamp. Second the modified after. So, this attribute can be used to read files that were modified after the specified time stamp. So, let's assume I am going to specify the today's date and whatever the file is received before today we just want to process those files or whatever the files that will be received after today's date we just want to process those files. So, these two options we are directly having inside the PySpark. First we can go with the modified before attribute and second with the modified after attribute. Let me quickly go inside the browser and we will try to see in practical. So, here we are under this input container and in the input container here we are having these two sales file. So, sales 0101, sales 0102. So, these two CSV files we just want to process and here we can see one file that is received on 29th of Jan 2024 and second file is received on 30th of Jan 2024. So, our requirement is first we just want to process the file which is received before 30 and the second file we just want to process which is received after 29. So, here for reading the data from the blob stories we can go with df.read method and after that here we can specify the option because we are also having the header. So, the header value that should be true after that here we can specify we just want to read the data from which format. So, the format that is the CSV and here we can specify the path. So, the path is very straightforward we have already created one of the mount point that is MNT under that we have the input folder and under the input folder which files we want to process. So, we want to process the file the name is sales.anything. So, the file name we want to process which is having the sales. So, let me try to put this into another data frame that is df1 and instead of df it should be spark because we are reading it. So, under the spark we are having this read method and then option then CSV like this we can specify. Let me try to use the display and in this display we can specify df1. Let me try to execute this cell and we will see the output from this. So, each file is having total 799 rows. So, here we should be having 1598 rows. So, that is why it is clubbed both the rows. Now, let us come to today's requirement. The requirement is we just want to use the modified before and after. So, we can specify the method that is modified after or before that you can see. So, let me go with before first and here we can specify the date and time. So, that we have already seen in blob stories we have the file which we have received on 29th of 2024 and the timestamp that we have. So, let me quickly specify time here. So, the format that should be 2024 01 30 and then we are specifying this timestamp as 00. So, what are the file that is received on 29th should be processed. Let me try to execute this cell and we will see the output. So, it should be having total 799 rows. So, that we can see now it is having total 799 rows and this we are reading from which file. So, this we are getting from the file which has been received on 29th. Now, if you want to use after here then it will be processed the file which is received on 30th. So, let me execute this cell and we will see it should be again returning 799 rows but this data we are getting from the file which has been received on 30th of Jan. So, these two methods we can use modified after and modified before. So, in the real time environment I have seen we are required to process the data which we have received the file on today. So, let's assume we have scheduled a job and that job is executing on 6pm every day and the requirement is whatever the files has been received on that day that should be processed. So, on those scenarios we can go with modified after and here we are going to check the today's date and the timestamp that should be 00 like that. So, it will be going to process the data which is received on that particular day. So, I hope guys you have understood when we can use the modified before and after and you can explain that to the interviewer. Thank you so much for watching this video. See you in the next video.


Before you can continue your session, I have a small announcement to make. The sessions after the lunch break about cell and cell art are free software by Enrico and auto building and experimental by Andreas and Martinus Faisalow will stretch their rooms. So if you would like to visit Enrico, go to the big audience T1 while the auto building and experimental session will be in the small room. So, thanks. Okay, so let's continue. The point I was beginning to talk about before the break was the whole topic of the layout and navigation and things like that. So what I would be interested in is should we try to develop a new layout? Should we try to make a competition out of this? I think some websites have good experience made with this in the last years. Let's take for example the Ubuntu page. I don't know if Mozilla was a competition or if this was something else. So, I would be interested in hearing your ideas about that. Yeah, I consider that the most important thing to say is form. My opinion is very important to say form follows functions and also follows content. So first I think we should really know what should this page content and information. Because you can't do a layout if you say, oh well, we're not sure what should happen with a page. Of course, a general layout also needs to be involved for the general layout. You might do it now and it might be a good idea, but really to say, okay, how the page should look like, especially for the front page, I think we need more than just a general layout. And that can only be done if you know what should be on it. Okay, so the point was, can we make a layout when we don't know what we want to change else on the side? And he said that you can only make a layout if you know the content. I disagree a bit. What you have to know for the layout is a bit about your navigation. So what do you need on navigational elements? So do you need only one list with some short links like we have on the top of the page? Or do you need a real menu like here at the left? That's things that have to do with the layout. For most content, I don't think that the frame in it is presented in really matters. The layout only has to make sure it doesn't waste too much space from the page so that the content is actually visible. But I don't think that it's one point of good layout that you don't have to change it for every page depending on the content. I just think you need to be sure how the main content looks like. The main content I'm being seen is like, okay, what's the navigation? What is the side structure? Should we move sub-projects or something else? These things need to be fixed before we make the layout. Of course, the layout is not a problem, but it tells the latest devs that this is the one or the other for work groups. We basically meet in the middle and say that some content is important, but the examples he mentioned were actually the navigation elements. I guess we some kind of agree in the end. You have to know what general links you have in your navigation structure and the real content doesn't matter. Okay, that's it. During the break, we've been discussing me and Fabian about, again, like user analysis as something which should become a bit more central. It's quite common in literature to see that if you find out that you have different kind of users, then you have to develop a different kind of interface and different kind of application to actually address them. I mean, so this user thing is so central that it should at least be part of the talking. And so we've been discussing a bit what could be the users of our website. And well, the developers we've been discussing before they're not addressed at the moment. There should be links to all the statistic page on people, NM people, and there's all the documentation around there. So they should be quite fine press. They look at the website, which is quite inappropriate for them at the moment. And the layout for press people, it would be absolutely the layout of the content. It would be absolutely different than whatever we are used to because you have to feed them the news, basically, which is short and to the point. And then after the news, all the pointers to the background, a little bit what DWM is doing actually. So DWM could be a source of news for the press, but could be expanded, I don't know. There could be some thinking about it. But we already have three web pages, three websites, sorry, or three parts of the website. And then there's Debian users. And we have to see if they fit there or not because Debian users is like anyone from a physical lab person doing quantum analysis to someone implementing Debian in a junior in a primary school, installing tux paint. And while we've been discussing if that isn't better left to the CDDs instead and maybe providing Debian stuff for developers or if the users could go in the press page. I mean, all this sort of discussion, if you think about it a moment, really change a lot what could come out of the website distribution, the website content. Okay, so he was making the point again that we really need to think about what users we have on our page and what do they seek to adapt our content to their needs. So we already discussed much about the developer aspect. But what he also mentioned was on the one hand the press, let's take someone from the press. He wants to have the news and he wants to have some concise information about the background, about general information about the project and things like that. And that's really difficult at the moment because the news are very split up and the background is on different pages. So that's an example for a user that's probably not self-good at the moment. And the last point are obviously the Debian users. So what do they want, but that very much differs because they are very different kind of users from system administrators who want to install large classes of Debian to people that only set up a small pool in their school or something like that or end users that only want to install their own computer. So the question is whether you can really make a page that gives them all what they want or if you have to guide them to some CDDs also that are more specialized for their needs and to make more emphasis on this. But yeah, so that was basically what Enrique was saying. And I guess the idea of trying to make such kind of analysis is really a good one. But how do we start with this? So do we make a discussion on the meaningless and say what are your users? Let's say something about this. How would you start with this? Let's try to make a discussion again. Should I answer? There is a raise hand down there. I don't know. Okay, let's make our first. I think the question is what should be on. One of the most difficult questions. One thing should be to take a look what the people are currently looking for. But it's only for the part of the picture because if it's not there, people will only look once for it. Because it isn't a work for me. So it's only half of the pictures. It's the other half. It's either to reconcile them, to speak with people and say okay, first to sort ourselves, okay, what could be useful? And then sort it, wait it in the end. Put some stuff in because we shouldn't have too many stuff on it. And perhaps also as some users you have seen have for example backed up for about the video saying okay, what do you expect? Because we know they are more interested to work with us than just average. But they are perhaps not as deep in as we are because everyone of us should be fairly easy to locate some information because we just know a lot about it. Okay, so the point was user analysis can consist of two parts. The one part is to analyze the current usage of the page and to see what users are using more and what they are using less so that you can find some information on which parts you should work because they are really important. But the other part is to find out what are people missing because they obviously can't use it but it's missing completely. So it's also important to get feedback from end users and trying to find a way to ask them. Yeah, well, in an ideal world you do all sorts of sociological stuff and interviews and which, okay, we can't. So we have to improvise. Either we do like some tiny fantastic thing like linking a small survey from every page and then see what's the profile of people answering from every page and so see what different kind of people are looking for. But that's, again, maybe more trouble than it's worth and there's a lot of risk of doing it wrong because we are not scientific knowledge researchers, basically. Or we can go really back driven. So suppose, well, we have some idea like press and M and D bells. I guess we have them. And so like start with something simple for them and maybe like keep the old website as like the everything else stuff. Like some like make some intro, like some, well, some homepage. There's no decent name. Like some personal page, some main page or main page for all these groups, for each of these groups. Starting simple and then see the request you get. Okay. And see not to always answer the request from the same person because that creates his own homepage instead of like the homepage. And then in that way, I mean, while doing that, you establish some kind of contact and you try to outline a picture of the person you have in mind which could be like even like an idealized character which you could describe and use as a reference. I don't know if people have read the inmates are running the asylum, which is a funny book as well. That's a book called... Didn't I send it acoustically? The inmates are running the asylum. The book is pretty nice and explains this technique a lot. It's a nice way of sharing the concept of the target user. And so like portraying this picture maybe as you go because we already have a website or like portraying an hypothetical one and discussing about that maybe like, oh, this guy makes the press release providing it and has little time for it because it's got tons of sources to track and you define it a bit in detail and you start designing for it. And then if that doesn't work out, then you try to find what's the shortcoming of that and you design another persona. That's the name of this thing and you refactor the website for this other persona and maybe that works better. That could be a process. So the main suggestion from Enrico was that what one could do was to create different starting pages for the different users we have in mind. So let's make a page if you're someone from the press and want to know something about Debian, go there. If you're a user, go there. And so that you have this as a starting page and link from there to the old content to the things we have right now and then to get some feedback about so that you have a starting point where users can comment on and give feedback about. Because other means of analyzing users like making surveys and stuff like that is much work and it's easy to do wrong if you're not experienced in it. So that's very problematic. And the other thing one could do is to make a discussion where you invent certain users and use cases you think of them and then try to go with them to the page and see where in their use case there are things that lack and problems so that you make different examples and try to analyze where they would run into problems. I don't think we should try to get people to feedback that probably won't work. I don't think people... Well, very few would leave feedback. Whenever I go to a website and see please leave feedback, I just ignore it. They pop up a window saying please fill out in our survey, I just close the window because I hate doing this. And a lot of people would probably do that. So we might get a few comments but we won't get... I think we'll get a representative view from trying to get user feedback. So I think it's better to try to figure things out to try to do the... try to think that use cases and build something and then maybe add something. You can comment here if it doesn't look good but you should try to... you should try to decide it before... I think. So the point was users are lazy usually so they don't give feedback and if you get feedback you get only a very selective view because only a few users provide it. So he thinks that the point about making hypothetical use cases and thinking them through is actually way better because that just works and doesn't require someone else to do work for you. So there was... Before doing use cases it's better to design personas which is like... I don't get the difference. No, well use case is what you offer them. Like the actions you offer them you support for them while the persona is who they are is them. And before designing use cases you want to design use case for whom. Because like getting news for a developer is very different than getting news for a press person. Okay, so the point was you don't have to create use cases but you have to create personas so that you have hypothetical persons that use the web page and to try to different kind of them like a press person that wants to make a general article about Vivian so what would he look for and thinking that through from their point of view and don't fall into the trap to just say all people want to have news because that's true but they want different kind of news so you have to think from their point of view and not only from the items you want to offer. Also looking at it from the other perspective from the people who are actually going to do this we probably need to adjust the process so that the people who are using it to do anything can actually make use of it. So what I'd like to ask is what kind of experience does this group have with this kind of development methodology? Do you all understand what a persona is and what a use case is or is this just mumbo jumbo that sounds fancy but doesn't really mean anything? So you are mainly asking the audience if they have already experienced with this kind of development so that you're trying to take the view of the user and try to develop from there or if that's really at the moment something that sounds sensible but you don't have any experience with. So let's take this point and then ask if someone wants to answer this. Yeah, just a re-question. Has anybody yet gone through the logs and tried to track down exactly how people use the web page? I mean it's good to think about hypothetical use cases and hypothetical personas but it would be ideal to figure out where people actually are entering the site from where they're going, what the commonly used information that we actually provide is. So the question was has anybody looked at the logs so has anyone tried to get information from them and the simple answer is I don't guess so. So, no. Sorry, www.devn.org is currently on Klecker which is a restricted host. Okay, so Paaske added that the logs for the main mirror for the www.devn.org not for the most are on Klecker currently which is a restricted host because it's also security.devn.org and so they are not really available but that's no problem. I can just give them to anybody who wants them and I even think that... I don't know, no normal website users don't have access. Okay, so the logs can maybe be available if there's a volunteer who wants to make some analysis out of the logs and he can even have other logs from other mirrors. We have some on deviant machines like www.us.devn.org which is on Glock so you can take a look at the logs there too. And so that's mainly about finding a volunteer who wants to do that. The technical stuff can be made possible. If you want to do that I suggest you get a friend who's in sociology and you feed them the whole logs and tell them to make a thesis out of it. That's the best way to do this stuff. But I don't want to wait for half a year for another site. Why? Okay, so the suggestion from Enrico was that one should try to find someone who is interested in sociology or something like that to help with that because it usually gives some results you miss otherwise. So the question was have people experienced the user-driven development? I don't know if that's the correct name or if it's the correct name for this kind of thing. Sounds fishy to you or... Put up your hand if you have ever started making a program without opening your next editor first in the writing program. Okay, that's a few. So... I guess what we would need for something like that would be someone collecting some useful resources about this. So let's say, okay, if you want to do this let's take a look at this web page or if you can get this book and read about it and then we can start with it so that we don't make every fault, every other people that have to try to do this before we also make again. So if you want to do this, you're welcome. I just sent to the web conf my English link about personas to show any article I just found on the web could be an interesting read. Okay, so Enrico will send some information he already has to the conf main list and I will forward this to the Debian website main list too. Yeah? I can also do some digging but I think it's important to get the doing started so we don't need to wait for everybody to get the PhD in user analysis before we do this. We can just start and fix things later once people have learned more. Okay, so he emphasizes that you don't have to read all stuff before you can start because it's just delayed it's not useful so you can start and then later when you know more just refine your results and fix everything you have made. In the meantime, if you want to get a PhD in user analysis this afternoon you can talk, that's the topic. Yeah, okay. I'm really interested in this we could even make it off at a later date at the conf, I don't know. I can just, that's it and if people are answering yes, I want that. I will write the domain list to the IC channel and see about feedback and I will usually request a spot if... Okay. So, other topics you want to talk about? Are there any? So before I just pick another one from my topics and ignore you? Well, I think we should do an only sort of start page but also there are a lot of how I should say, very depth licenses where you can go to for example if you are near the mirror list you don't need to go to a few steps away to get to the mirror list. It took me some time for asking me to find the actual mirror list. It should not happen actually. So, I think that's just an example and I don't have any idea how to do it but I think there needs to be a massive cleanup of the link pages. Yeah, okay. So the main point was that the links are really suboptimal at some places and one other example one user gave me last week, I think it was in Buckleyport or in the main was was about so you are getting Debian and... Yeah, the download link is also very good. Mega CDs, I guess. Oh no, that's not right. Okay, no. So, go on the download one. Download the next one. Oh yeah, see here it was.  So you have another link.  There's nothing on it. Just a link to the install menu. The problem is there's no link so you have to go to the install menu let's say for something where there are actually floppies. So, now let's take the HTML. So, yes, now let's see let's see, it's actually made of floppies. Oh, another link. Floppies. Yeah. Yeah, okay, there's nothing. Let's try something else. Opting system installation media, let's try that one. So, maybe it's what we want. So, yes, that's a pretty much good example of what shouldn't happen. Go on a link that says get floppies. You want to get the floppies and not ten links to other pages where then we can actually get the floppies. So, that's a good example of something we want to fix. Other topics you want to discuss about? No, that's not actually the case. So, what we're still interesting about and we have left this topic I started because of the more interesting stuff we have then discussed. It's the whole layout question. I for myself, I can't make layouts.  So, how would you search for a new layout for the website? There are many people that have complained about this and so, would you just search for a volunteer? Would you make a competition? I would be interested in that because I can't do it. So, I have to find someone. How would you make this have someone experience with this? I think we have a set of people who make at least these layouts in the area of Debian and why shouldn't we just ask them if they want to provide a second side of my project and then we can of course discuss which looks better and who have good ideas about how the navigation should be and which of the sides the second step after fixing how the navigation should be. Okay. So, we just should just ask people but we need to have some information first to give them a better idea of what we are searching for. So, perhaps we should wait a little bit because we have really an idea about what do we want us to change before we search for a layout and then we later realize that doesn't fit us at all. Yeah. It would also be nice to get all pages that's more or less the same layout currently figured from here in the developer's corner at least the whole top navigation That's the left-hand side all that disappeared. Okay, good. We currently only have the extensive menu on the left-hand side only on the front page. So, the question was whether we want to make a more concise layout but the navigation elements don't change. Things like the CD page are also a question of course because it has a completely other layout currently and it would be interesting to see if we should merge this and I really think we shouldn't have a different layout for the CD pages but I don't currently want to impose on them the layout we have for the main page because it's crap so I invest the work into doing this and then better change it anyway. Okay, if there are no more things about that topic what I also wanted to hear is there are some people here that already work on the web pages some others that don't What I wanted to ask you is do you think it is particularly complicated to work on the web pages currently is there something we would need to change on this is to make it easier for contributors or something like that Split the users page Okay. One thing I find particularly hard but for other people if something goes wrong even if it's a main cloud file which will restrict the toast That's not true It's not obvious the documents that are available of course I myself can log into Black and look up and say, oh that's very good I think it might be better to document that from better I suspect you just have looked That's the thing it's hidden very well here on the web page Let's see if that's one good example for creating or editing pages There's a link here somewhere but it's obviously not on the page you would look for it The question was whether there are the build logs available since the page is regenerated with the VM error and you don't have the log files to look for problems especially if you change big things The point was that the build logs should be on the which is not true It's available via HTTP but the link is hidden It's right on the first where it's the first link has recommended reading next to it and it's a bit down at the how to help previous page previous page on the desk no, it's on the desk page the first link down to how to help how to help Ah ok, you have the build logs Yeah That was obvious Of course Ok We see we can find easily examples for what we don't want or what we want to fix So And in this link that's still not what I use most often are logs from the from the documentation sub-watcher and I don't think so That's not a real problem I'm just looking to click normally Yeah, that's how I find out about my rejects but on you But it's another question So Yeah We have only 5 minutes left so if there's nothing if there's not another topic which I think we can leave this here and just end this discussion I really want to follow up on the user on the idea of inventing personas and trying to fix some things and eager to read the links and we'll propose how to go with this Ok, so and I will try to summarize our discussion about this whole log-in stuff because we're not really getting to any decision or even a majority meaning or something that we should discuss this further There are obviously problems with CMS as the whole maintenance stuff and things like that so we should really discuss it and I will try to initiate this discussion on the Debian website maintenance so if you're interested in this point just go there and participate in this Ok, thanks I think it might be worse to make the use cases discussion because it's really not too hard to say everyone trust the whole use case we make a profit on Saturday or so and then we can summarize it up because if you're all here, it's much easier to discuss than by a main listener we have a salz if you believe that ok, so the proposal the proposal was to try to get the buff organized so that people that are interested in can start a little bit with this persona and try to get some first impressions and ideas about that I will propose a date do you have any no Saturday today is the formal dinner so that's not a good idea speaking of releasing everyone should just make one use case in about 2 or 3 minutes because then we have a lot of information yes there is an amazing find for a date we just got the weekend because of our time so they've come 5 at hot buck changes the changes link what did somebody do there? we have Thursday today it's already almost Sunday so we have Sunday no not really maybe we might hope we can just make a parallel to this ball from 8 to 9 and we just make that hot buck at the cabins place so your suggestion was to to make it a parallel to the start of the ball because the ball takes about 4 hours and we can just in the first hour parallel we can meet down the stairs down the stairs where also the Helsinki proposal was made so the suggestion was to make it a Saturday at 8pm because the linux ball is about 4 hours planned here so we could easily make an hour to discuss some of our stuff but of course also I don't know what's up with you but I don't like to keep it in parallel for example with web apps policy or with web apps policy or with the data and workflow management okay yeah I will write it on the mailing list and you can comment on this then um okay um yeah okay I like this suggestion to just make it at 8pm on Saturday is there anyone who has a problem with this okay so let's do that and who has to zoom go to stairs down stairs at 8pm stairs at 3pm and two bands and you just have to bring some chairs because you film also four people yeah okay I remember the photo Amaya posted it too okay so yeah okay let's stop this here and we hopefully meet some of you at Saturday some of you on the mailing list after this so thanks for the discussion


Welcome back to the channel everybody. We are back fishing down in Austin, the Silver Bullet is parked here at the tree house waiting the next adventure. But we've got adventures here. So today is gonna be a home blog and there's always something going on here at the tree house it seems. We call it the tree house because it's literally just sitting in the trees. There's always some sort of issue and we're constantly battling with the home itself whether it be cracks and things shifting and moving which is kind of normal from Texas. Then we also have the wildlife of the woods. So the carpenter ants and just things like that. We've got lizards and snakes and just the typical stuff that you would expect. But then we also have these other varmints. I mean the mammals, the bobcats, the coyotes. We've got hogs. We haven't had the hogs in a long time because it's been so dry. The ground is extremely hard. Then we have raccoons and then we have possums and foxes and armadillos and just about everything you could imagine comes into this yard on a pretty frequent basis. I feel like we've done a pretty good job keeping the pathways clear. You know having some safe places for Emmy and Ben to play and not have to deal with the snakes and stuff like that. But the rodent creatures, I forgot about the rats. We've had rats inside of the house this year. Perfect example I just discovered two days ago. And this isn't even the creature that I'm not sure about yet. This is definitely a mouse. But if you guys just look right here, a rat or a mouse, whatever, has been chewing on the AC insulation around the pipe there. The pipe's real cold so I don't know if they're just attracted to the coldness since it's so hot outside. They're definitely getting in the house though through that hole. But that's not even the creature that I'm upset about. The mystery creature that I'm upset about is tearing up the yard, terrorizing the yard. And it's not a hog.  I don't believe it's a raccoon but something has been going through the yard, going around the house, the base of the house, digging up, tearing into things and just tearing up my grass especially. Now I hate to be the get off my lawn guy at this stage of my life but I feel like I'm getting that way. The last three years I've struggled to get decent grass growth in my yard. I mainly wanted it for erosion purposes. I finally got it this year. It's looking great. All the neighbors are going, dude, what are you using for seed in your yard? It looks so good. I was out there watering it twice a day. I had the sprinklers dialed. You know what I'm saying? I mean, if you middle-aged guys know what I'm talking about, holler at me in the comments because once you get that grass set up growing, I mean, nailed it in the spring to ride out the heat of summer where it's 100 degrees for like 30 days of row here in Texas. But now all that has been screwed up. And I'm just walking out every day to new holes. This has been a few weeks. And it's not just the grass. It's also the plants. OSG is pissed. So she's on me to do something about this creature. It's tearing up her plants and her flower beds and all that stuff. It's even broken one of her favorite little clay pot things. She had some baby wipes in it or something. And I come outside two days ago. The pot is broken on the ground. I'm like, what is going on? We're being attacked here. So a first line of duty. We need to figure out what this actually is. It's been a long time since I've broken out the trail cameras around here. I took them off. The deer lease have been sitting in a box. It's time to break them out. We're gonna be putting them out at the deer lease soon. Anyways, so we're gonna get some cameras out going. And I've already put out some traps. Now let me show you guys what was doing the digging and obviously we're dealing with something clever. So we put in this Jasmine this year. Stephanie did this. This is her little project. And it started to uproot the Jasmine. I know it's hard to see. There's a lot of shadows here, but it's just digging in here and Stephanie's having to come out here each day and recover it with the mulch and the soil because we don't want to stuff dying. This is what prevents erosion. Our house is dependent on erosion at a minimum.  So we're constantly battling that. We come in here to the flower beds. As you guys can see, it's something's digging in here and getting worms. So it makes me think, worms, beetles, whatever it makes me think. It's like an armadillo or a possum. But the whole pot thing breaking, I want to say that's the old five finger raccoon. But I don't know. Come around to the other side of these beds and you can see a paw trap that I've got laid out here. And last night I set out some shrimp. We had shrimp for dinner. We put some leftover shrimp on there. They were all eaten, but the trap didn't go off. So that's probably a poor job on my part setting this up. It was just kind of a last minute thing. And then it went over here, tore it up, tore up under the azaleas until we reached this soaking hose. So it's dug up all around the soaking hose. There's even a sprinkler pipe that's exposed now. This is all just from last night. We're having to come in here every day, rebury this stuff. Also, we've got chicken updates. Let me take you in here. Also wrote a problem inside here. I'm pretty sure I fixed the issue, but there was a possum that was getting in here and eating the chicken's food at night. Luckily I have this coop door. I've got this automatic coop door and that closes them in completely. So possum could not get to these chickens at night. The chicks I've had in a very small enclosure. It was getting in through the top here. So I took this board, I put that on there and put this other board. And now there's just this little tiny hole. I mean, a mouse could get in here, a rat or something, but I don't think maybe a very small possum could get in there. Not one big enough, I would think, to do much damage. And I've completely redone the pullet and cockerel enclosure here. So let me show you guys this. This is pretty neat. I've been working on this for the last couple of days, but I took some paracord and I've run it on these poles. I way overbuilt this chicken run and I'm glad I did because so many things lurk around here. But what's nice about having these structural posts in the middle is I can separate sections off if I want to and kind of put it in quarters. So I've got a quarter of the run here that's enclosed.   Any sort of leaf will get caught up in it. Anyway, it got all balled up. It is a complete mess. It started out as a 50 by 50. It ended up as such an odd shape that I just draped over the paracord. And it's working pretty good so far. It's been up for two days now. And the pullets and one cockerel, which I have now identified, are loving it in here. They've got a bunch of perches. It's really cool. I mean, I actually take you guys in here. Colonel Sanders, he can't get in there. He doesn't like the netting. They don't like it when they get caught up in it. It catches everything, including my hat. Say hello to the world. This is my frizzle cockerel right here. You can tell he's gonna be a male. He's already got those waddles and comb rocking. And I think the other frizzle is a female. Look at the polish, man. Polish is crazy. And there's that frizzle. They just come up to you, which is nuts. Just come up to you. They'll let you cut them. They're really soft. They're watering these plants that it looks like fall out here because the dead plant and the dead leaves. And now we've got holes everywhere. Did you show them all these holes? I've been showing them, babe. We're gonna try to fix that tonight. I mean, last night, you and I talked about it. We said we were gonna set out some traps. We had that leftover shrimp, which was perfect. It was a good attractant, but whatever it was, eighth of shrimp did not get caught in the trap. So I'm gonna try to fix the trap where they have to walk over it instead of being able to peek in there and just pick it out. I vote that it's a armadillo. You think it's armadillo? I think it's an armadillo. I'm on Team Possum right now. You're on Team Possum? I am. Nobody's on Team Raccoon? I think the raccoon did the clay pot damage, but I don't think it's digging in the ground after worms. It'd have to be pretty desperate. There's plenty of trash cans it could go to. That's true. The raccoon on our property goes for baby Ben's diapers. Like a couple of times I see like, it is disgusting.  We need to get like a trash can cleaner out here. Well, that would be me. No, we just live in the woods with raccoons eating poopy diapers. So I had to do some digging, but I found all my old trail cameras from the lease. Some of them have been beat up by hogs and cows and like a few of them were broken. So I found one that is working. I just put some batteries in it. So let's go ahead and let's set up this cam on one of the trees here. This is the higher tree. So it should work out. I placed the cam here. All right, so we got our camera set up here in the app and I just got to change the notifications to get images immediately and then we'll be ready to go. Now for the front yard defense. This is what I'm talking about. This is everywhere. These, I mean, these are big holes. These things digging in and then the grass is done and it's new ones every night.  Look at this.  Just destroying my grass. These are the areas that are just dead. They're dead from all the rooting and I'm not gonna tolerate that. That is not gonna be tolerated here on this grass. Flower beds, same thing. You can see last night that the shrimp shells all the rooting around it and we didn't get trapped. So I'm gonna basically create a funnel somewhere where the animal has to step over that and gets caught in it. So I'm gonna have to take some boards and just create a little path for that thing to step in. So as soon as that server kicks on, I should get immediate updates if something walks through the frame. Next step, we're gonna get some boards. We're going to get maybe some logs and we're gonna set a path for this animal to have to go through. Most animals don't like to step over stuff. They're gonna take the path to least resistance. So I'm going to put some salmon skin. Stephanie is cooking up salmon tonight. This is perfect because it really went for the shrimp. So I'm guessing it likes fishy stuff. So we're gonna take some salmon skins. I'm gonna just kind of trickle it in there. Just trickle it in in this path that I'm gonna make and then I'll put a wad of it on the backside of the trap where it has to walk over it and hopefully get clamped on that. I have a big like cage trap but I've set it out before and I've never gotten anything. I think it's just, it's a lot. It's a lot of convincing for that animal to go in there. I just like the paw traps because A, I mean, if you catch something crazy and you want to let it go and it's not your target species, you can let it go. And B, like they can't see it at all. Like it's buried on the ground so they're gonna most likely step in it if you set it upright. I didn't really set it up like right last night. I set it up where they could walk up to it, eat on top of it and you know, you basically have to step on it for it to really pounce. It's not as sensitive as a mouse trap. So we're gonna set up the little funnel and then that's it. It's basically sitting on our trot line. We're going fishing tonight and it's gonna be dark here in about four or five hours. So hopefully we get something on the line. All right, we got our little funnels made. Let me show you what it came up with. I had these already from the chicken coop. Oh my God, it just bit me in the armpit. Have you ever had that happen?  Okay, anyway. So I just had these laying around in the chicken run. This is what used to hold their food and their water. So I just propped them up right here. It's nice because I've got these little boards on the back to kind of give it some stability.  I've got some salmon. So we'll go ahead and we'll put a little bit on the outside here, just a little taste, a little taster or two, we got it. Just a little something right there for you, a little appetizer. We'll put the back chunk right here at the back, just behind that trap. So basically it has to put its foot right there. Gonna be a juicy one right there. So we'll put it just right there. That should be enough stench. The stuff smells pretty good. Similar to the shrimp that it should work. I just got a ding in my pocket. Hopefully that's our, just got notification for the cameras, detecting motion. Not showing anything yet, got to connect, but it's definitely detecting us. So we'll run around to the front, do the exact same thing. And hopefully this is gonna do it guys. I mean, shrimp attracted them. I was tempted to put catfish bait, but I hate dealing with that. I think the salmon is gonna do it. Super greasy. Little chuckle, little appetizer, and then boom. Main course back there in the corner. I've got a whole piece of plywood. This is one I just had laying around. And I put some stakes on this little two by six right here. And I think that is gonna do it. Now all we gotta do is wait for nighttime. Hopefully we get a snap. All right, so it is about 5.45. And my son, he woke up crying at like 5.15. So I just reached over, grabbed the phone. And I looked to see if I had any images. And we had movement on the front yard camera. So I'm about to go outside and see if anything is in these traps. It's just kind of, it's just blank. It's like something moved through there, but I can't, I can't see anything. And that was at 5.04. So I'm wondering if it's like outside. That's near my, where my son sleeps. I don't know if it's like howling or, you know, squealing or something like that. So let's get the flashlight. Set outside. All right, we're gonna go check the front. See if there's anything in there. That's where the camera had the motion. There's nothing in there. So the skin is still there too. Don't see any new. Gonna go check the backyard. Got the first rooster crowing. Colonel Sanders is crowing. Oh my God, let's see him. Let's see him, we got him. We got him, babe. We got him. Well, look who it is. It's like this little Bilbo Baggins wandered into the wrong shire. It's time to get out the dispatch team. Look at him. It's like just plain dead. He's trying not to move. Your destruction has come to an end, dude. Yes, y'all, the traps worked. Those funnels worked. Now it is time to call in the dispatch team. We got a lot of options. I was actually up late last night working on one of my newer bows. We'll be doing a video on that soon. We're not gonna be using that. We could go full auto. With the one seven seven. But I think the best bet for the money is that guy right there, Old Red. Old Red's already got a light attached to it. Nice little tape job on there. Nothing's ready to go. Now if you'll excuse me, I have a date with the varmit. And we're going into the woods. One of us ain't coming out. All right guys, well the trap definitely did its job. Making those funnels made all the difference. You know, I don't think that is the last one either. I think that there's probably more around here. And I know for sure something with hands or thumbs, whatever, got into our pots like something sneaking around the house. So there's more varmints out here. Plus the ones that took out the last of our flock still lurking around here. So don't think we're done with our backyard varmit quest just yet, but we got one taken out. And I know OSG is going to be psyched when she's making her coffee in just a little bit. I go in there and I tell her, honey, I got the thing that was digging into the flower beds. That means browning points for me, ladies and gentlemen, I did my dadly duties. So thank you guys for tuning in. The sprinklers are just coming on right now. Perfect time. Just took down the cameras, incredible. Gonna do some more home vlogs around here. Got some bow making to do as well. And of course we'll see you out there on the water. So thank you guys again. May God bless you and all your adventures. Godspeed, we'll see you on the next episode.


Darshan Pandit, Assistant Professor, Department of Computer Science and Engineering from Walton Institute of Technology, Solaapur. So, today we are going to discuss about localization and calling. So, at the end of the session student can differentiate between mobile terminated call MTC and mobile originated call MOC technologies. So, localization and calling comes in two ways that is mobile terminated call and mobile originated call. Mobile terminated call or nothing, but the call originated from landline phone and terminating at your mobile phone and mobile originated call or call originated by your mobile phone. So, in localization and calling GSM performs periodic location update. So, even if a user does not use the mobile station, the GSM system always knows current location of a user because of his phone number which is valid worldwide. So, GSM uses two types of database that is home location register and visitor location register. So, HLR always contains information about current location. So, whenever MS moves into the range of new VLR that is a new location area, HLR sends all user data needed for new VLR. So, changing VLR that is visitor location register with uninterrupted availability of all services is called roaming. So, roaming can take place within network of one service provider. So, service provider are nothing, but BSNL, IDM, Vodafone, Reliance, so this all are service provider. So, roaming can also take place in two service provider in one country, so that is known as national roaming. So, roaming can also take place in different service provider in different countries, so that is known as international roaming. So, in order to locate MS and to address MS, several numbers are needed, so those are mobile station ISDN number, MSISDN, international mobile subscriber identity, IMSI, temporary mobile subscriber identity, TMSI, mobile station roaming number, MSRN, so let us see one by one. So, mobile station international subscriber directory number that is MSISDN is a number used to identify mobile number internationally. So, based on SIM, a mobile station can have many MSISDN as each subscriber assigned with a separate MSISDN to their SIM respectively. So, as an example you can see in the table plus 9-1 is a country code, 2-1-7 is national destination code and 1-2-3-4-5-6-7 is a subscriber number. So, international mobile subscriber identity, IMSI, so here every registered user has an original international mobile subscriber identity, IMSI with a valid IMEI stored in their subscriber identity module that is SIM, so it is an internal unique identification of a subscriber and usually presented as a 15-digit number, so in which first three digit are mobile country code, so you can see in table 404 is a mobile country code followed by mobile network code MNC, so it may be 2 or 3 digit and remaining digits are mobile subscriber identification number MSIN, so it is mostly 9 or 10 digit based on MNC, so next is temporary mobile subscriber identity TMSI, so this TMSI hides the IMSI where GSM uses 4 by TMSI for local subscriber identification, so TMSI is selected by current VLR, so this TMSI temporary, it is a temporary address valid within location area of VLR, so TMSI is stored in VLR and it is not passed to HLR, so next is mobile station roaming number MSRN, so it is another temporary address that hides identity and location of a subscriber in MSRN, so VLR generates this address on request from MSC and the address is also stored in HLR, so using MSRN the incoming calls are channeled to mobile station, the MSRN has same structure as of MSISDN that is country code of the visited network, national destination code, NDC of the visited network and subscriber number in the current mobile network, so just think and write what are the content of mobile station international ISDN number, so the content are like country code CC, national destination code NDC and subscriber number, so let us see what do you mean by MTC, so it is a scenario in which a call is made from landline phone to the mobile station, so where so you can see you are having calling station after that PSTN, PSTN is nothing but public switched telephone network, so it is a switching office to switch call from mobile and landline, so it is connected to a PSTN network, after that GMSC, GMSC is nothing but gateway MSC, HLR is home location register, VLR visitor location register, so you can see MSC, MSC is nothing but mobile switching center to switch the call between BSS, BTS, so we require MSC, so after that BSS base station subsystem and MSC is nothing but mobile station, so here, so in step 1 a user dials phone number of a GSM subscriber, so in step 2 PSTN that is switching office notices and power call to GMSC, so in step 3 GMSC identifies HLR that is to which HLR the mobile station belongs and signals call setup to HLR, so in step 4 and 5, so request MSRN that is mobile station roaming number from VLR, so if mobile station is present in visitor location register that is in new location area then we require MSRN after that in step 6 forward responsible MSC to GMSC, so in which MSC the VLR is present, so that MSC is forwarded to GMSC that is in step 6, so in step 7 forward call to current MSC, so whatever current MSC is there the call is forwarded to current MSC, so in step 8 and 9 get current status of MS that is in which BSS MSC is present we need to identify the exact cell that is in which cell mobile station is present, so in step 10 and 11 paging of MS that is identifying current location of MS, after that in step 2 by line 13, so we need to identify MS to get connected and in step 14 and 15 security check is done that is encryption setup is done, so in step 16 and 17 VLR signals MSC for connection setup, so in this way connection setup is done between calling station and MS. So next is MOC, so this is the scenario of mobile originated call in which mobile station calls a PSTN network that is landline phone, so in this we are having very few steps then compared to MTC, so here in step 1 MS transmit a request for a new connection in step 2 the BSS forward this request to MSC so you can see in the figure, so call is initiated from mobile phone in step 1, so after that BSS forward this request to MSC, so in step 3 and 4 the MSC checks if the user is allowed to set up a call with the requested service, so whether he has allowed to call the landline phone, whether he has subscribed to the service everything is checked in step 3 and 4, so in step 5 to 8 MSC checks the availability of resources through GSM network and in PSTN network, so in step 9 and 10 MSC setups a connection between mobile station and a fixed network. So these are the references which I have used to prepare this video, thank you.