So, in the last class, I was trying to motivate what we mean by passive circuits and the sort of conclusion that we arrived at was that passive circuits is something where the amount of energy that is supplied to the circuit, this is always positive and the amount of energy that is supplied to the circuit is bifurcated in two ways, a part of it goes into stored energy which gets stored by the energy storage, storing elements in the circuit and the other part gets dissipated, ok. So, let me write out an equation that sort of captures this idea of passivity. So, this equation is what is called dissipation equality and what it says is that power supplied is equal to dissipated power plus the rate of change in stored energy. Well, as far as dissipated power is concerned, this dissipated power is always going to be something which is positive. Therefore, I could take this rate of change of stored energy to the other side and I can always say that power supplied minus the rate of change in stored energy is some quantity which is always going to be positive. Now, in case of a circuit of course, what we can do is we can write this down, the power supplied is v dot i and so the stored energy is denoted by E then dE dt. So, v i minus dE dt is greater than equal to 0, this is greater than equal to 0. Essentially, this is in fact equal to the dissipated power and the dissipated power is always a positive quantity. So, v dot i minus dE dt is greater than equal to 0, this in fact is called the dissipation inequality and this dissipation inequality is always going to hold true for circuits which are passive. Now, how do we characterize circuits which are passive? Now, importantly, the example of the circuits that we were looking at, it has one input and one output and typically in circuits, the number of inputs is equal to the number of outputs because we think of circuits in terms of ports and each port has a voltage and a current and so one of them, either the voltage or the current you think of as the input and the other one as the output and so the circuits are the special kinds of systems where the number of inputs is equal to the number of outputs. So, of course, till now in the example that we were looking at, it was a single input single output case, but you could also look at a multi input multi output case where you have a whole vector of voltages and currents of various ports forming the input and another whole vector of the corresponding currents and voltages on those ports as the output. And then just like we talk about v dot i, you could just talk about the inner product of the input and the output giving you the energy supplied and there would be a storage function depending upon the number of depending upon the various energy storing elements which are there in the system and one could write out the dissipation inequality which says that the inner product of the input and the output minus the rate of change of the stored energy, this is always going to be greater than equal to 0 because this quantity in fact is going to be the dissipated power and the dissipated power is always a positive quantity. So, let me just constrain myself to a single input single output case and let us say the single input single output situation is given using a transfer function as ys is equal to some gs us where y is the output and u is the input. Now earlier what we had said was that u transpose y, this is the same in the case of the electrical circuit v dot i is exactly the same as u transpose y and we are saying that u transpose y integral from minus infinity to plus infinity, this particular quantity should be greater than 0 then the system is passive. Now if you are going to take the integral from minus infinity to plus infinity of u transpose y, one could take the Fourier transforms and if one takes the Fourier transforms this is the same as there would be some scaling factor k and minus infinity to plus infinity of u j omega star times g j omega g j omega star y j omega. But of course, this u transpose y I could really write it down as half of u transpose y plus half of y transpose u so sort of making it symmetric. Therefore, along with this expression there will be this other expression also which is y j omega star g j omega u j omega. So, this integral of course, this is over d omega so this integral would be equivalent to this integral after having taken the Fourier transforms so we have taken Fourier transforms. Now if you look at this expression this is the same as saying well I think I have made a mistake sorry so let me do it again. So, if you are looking at this from minus infinity to infinity of u transpose y dt this is in the time domain. This is equal to some constant of proportionality of course is u transpose y u transpose y I could write it out as a half u transpose y plus a half y transpose u.  So, last time the mistake I made was that I put this g j omega in between. Now I can bring in the g j omega by substituting you see why once you have taken the transforms y j omega is really g j omega times u j omega and so substituting this and there we would end up with integral minus infinity to plus infinity.  Now of course when I write this down there are several assumptions that are going in. The assumptions that are going in are the following. For example, we will assume that u is a compactly supported trajectory that means if this is the time axis u is non-zero only over a compact set. Now if u is non-zero over a compact set then it is easy to take the Fourier transform it makes sense to take it Fourier transform. Now if u is compactly supported because the transfer function tells us that y is equal to g times u this is the equation. Therefore, the Fourier transform of y also makes sense and if u is compactly supported in the circuit we can expect that y is also compactly supported and so then it makes sense to take the Fourier transforms. Now if you take the Fourier transforms the Fourier transform of y and Fourier transform of u is related in this way and so once you have this expression you substitute and you get this and now this integral is greater than equal to 0. So, if you look at this last expression whatever u you choose this expression must be positive and now one can show that this expression would only be positive if g j omega plus g j omega star is greater than equal to 0. But this here is really the real part of g j omega and so the real part of g j omega must be greater than equal to 0. So, this condition is the condition for passivity and the condition for passivity translates to and here of course we are only considering single input single output case. So, the single input single output case the y and the u the output and the input are related to the through this transfer function g of s and then what this translates to by this set of manipulations is that the real part of g j omega must be greater than equal to 0. So, let us look at situations where the real part of g j omega is greater than equal to 0. What does that mean? Now you see the expression that we had is g j omega plus g j omega star but this is the same as saying g j omega plus g minus j omega. Now if g j omega can be written as a plus j b then this will turn out to be a minus j b. So, the imaginary part gets cancelled out and you are just left with the real part. So, this being greater than equal to 0 is the same as saying that the real part of the transfer function g j omega must be greater than equal to 0. How to translate this condition into something more meaningful for us? One way we can translate this condition into something more meaningful is you see the image of g j omega is a Nyquist plot. So, saying that the real part of g j omega is greater than equal to 0 is the same as saying that the Nyquist plot of the transfer function should lie in the first or the second quadrant because then the real part of g j omega is going to be positive. So, what this translates to or whatever we have been doing till now this result that we have got, what it translates to is that the real part of the transfer function g j omega should be positive and what that means is that the Nyquist plot is in first and fourth quadrant. But as it turns out this Nyquist plot being in the first and the fourth quadrant is not a complete characterization of passivity. That is because mathematically the Nyquist plot lying in the first and the fourth quadrant may not necessarily translate into that particular condition that we had where you have a storage function and supply function and that interpretation that you have. First, let us look at some examples of transfer functions which are positive real. So, I did not mention that. So, those transfer functions whose Nyquist plots lie in the first and the fourth quadrant well one definition for that is positive real. So, positive real transfer function gs is such that the real part of g j omega is greater than equal to 0. I cannot claim that this is the definition of positive real because depending upon various books the definition of positive real changes. Now, the earlier interpretation that we had for passivity the one would like to say that positive real transfer functions is equivalent to passive. But that is actually strictly not true because if you give the definition of positive real to be that the real part that the Nyquist plot lies in the first and the fourth quadrant then one can show that there are some transfer functions which will satisfy this condition of positive reality but are not actually passive. So, it turns out that in many books they use the definition of positive reality to be the fact that the Nyquist plot lies in the first and the fourth quadrant whereas in many other books the definition for positive reality says that the real part of the transfer function evaluate that means the Nyquist plot lies in the first and the fourth quadrant but in addition the transfer function is stable. So, now I would give some examples to try and tell you what exactly is the difference between defining positive reality in this way and defining positive reality in the sense of this plus gs being stable. So, let us look at some examples. So, suppose you look at the transfer function gs equal to 1 by s. Now, this transfer function is it positive real? Well, if you just take this definition then g of j omega is 1 upon j omega this therefore the real part of g of j omega is equal to 0 and so the real part is greater than equal to 0. So, one can say that this transfer function is positive real. If one uses the definition that positive real means this plus gs is stable if one uses this definition then again this particular transfer function is positive real because the real part is actually 0 and this is also stable means s being a pole at 0. If you think of that as stability or marginal stability or whatever goes then one can still continue to call this positive real. So, the definition of positive reality could be just this or could be this along with gs being stable. Again, as I said earlier it depends on the books that you follow some books use only this definition but most books use this definition plus the fact that gs is stable. So, let me use a few more examples to show why there is a difference between just having this condition which is the condition that we got from the earlier equations that we derived and also having this condition that gs is stable. So, let me take another transfer function gs is s plus 1 upon s plus 2. Now, if we look at the Nyquist plot of this, the Nyquist plot of this at s equal to 0 it is at half and then so, this particular transfer function has a 0 at minus 1 and it has a pole at minus 2. So, as you go up you find at any particular j omega there is this angle which is larger than this angle and so it is going to be positive and as j omega tends to infinity this finally tends to 1. So, you end up with a Nyquist plot which looks like this goes to 1 and then when you look at the rest of it this is what you get. And so, it is clear that the real part of g j omega is greater than equal to 0. So, by that definition that the real part of g j omega is greater than equal to 0 this transfer function is positive real. Of course, if you also put in the fact that it should be stable well this transfer function is also stable. Therefore, by both the definitions this transfer function is positive real. Let me now take another transfer function which is gs is let us say s minus 1. Now, this transfer function of course is not stable. Now, if we were to draw the Nyquist plot of this it has a pole at minus 1 at plus 1 and it has a 0 at the origin.   And this then turns out to be so perhaps I should not use a minus here I should just put plus. So, if I take this transfer function so s upon s minus 1 this is not stable and when you calculate this is plus and so you get 1 plus omega squared yeah. And so in the numerator so the real part will turn out to be omega squared upon 1 plus omega squared. And this quantity here is greater than 0 for all omega greater than equal to 0 for all omega. So, if you use the definition that the real part of the transfer function is greater than equal to 0 then this thing is positive real this transfer function is positive real. But if in addition you also put in the condition of stability this is not stable therefore, this transfer function is not positive real. Now the question is why was this condition of stability brought in to associate these transfer functions with passivity. Now that is completely dependent on what one would call the storage functions. So, it turns out that if you have a transfer function like this you are not going it would not be possible to synthesize a circuit which has this transfer function using purely passive elements. And the reason for that is because this g of s is not stable. As a result the associated storage function that you would get that you can get for this particular transfer function that storage function is not going to be positive definite. So, let me explain what I mean by that. So, earlier I had said that the storage function is a bit like a Lyapunov function that means if you set the input to 0 and then you look at the system then the storage function plays the role of the Lyapunov function. Now the Lyapunov function of course, has to satisfy certain conditions that is one of the conditions being that the Lyapunov function must be a positive definite function and its derivative must be negative definite. Now the fact that the derivative is negative definite will get satisfied because of the dissipation inequality. So, just recall that the dissipation inequality gives us something like this U transpose y is greater than equal to d dt of E where E is the storage function. But now what does this mean? If the input is 0 of course, this quantity is 0 and so 0 is greater than d dt of E which means for the system with 0 input this E can act like a Lyapunov function provided of course E is positive definite. So, if E is positive definite here this thing essentially tells us that the derivative of E is negative semi definite and as a result the resulting system, the system that you get by setting the input to 0 is a system which is stable. Therefore, it is important that this storage function that you get should be positive definite. Now when we use the definition of positive real transfer function to be equivalent to the real part of g j omega greater than equal to 0 then this condition alone gives us no guarantee about the positive definiteness of the storage function. So, this condition gives no guarantee about positive definiteness of E. So, that is why many people would like to call a transfer function positive real when not only this condition is satisfied but it also guarantees that the storage function that would result in the system is a positive definite storage function. Now in fact the guarantee for that is given by a famous lemma which is called the positive real lemma and so let me state the positive real lemma. So, let us take a transfer function g of s which is stable and let us assume that this transfer function is written in as a state space model and so you have equations dx dt equal to ax plus bu y equal to cx plus du and let us assume that this representation is a minimal representation. So, minimal representation essentially guarantees that ab is controllable and ac is observable. So, what we are saying is we start out with a transfer function of course I am just restricting myself right now to single input single output case. So, we are taking a transfer function which is stable look at the state space representation and the state space representation that we are looking at is a minimal representation which means the ab cd matrices are such that ab is controllable and ac is observable. Then the real part of gs is greater than equal to 0. So, gs is already stable that we have assumed then real part of gs is greater than equal to 0 if and only if there exist matrices p l w of appropriate dimensions such that so what we are saying is that the real part of gs is going to be greater sorry the real part of g j omega is greater than equal to 0 that means the Nyquist plot is going to lie in the first and the fourth quadrant if and only if there exist matrices p l and w of appropriate dimensions such that the following three equations hold and the three equations are a transpose p plus p a is equal to minus l transpose l p times b is equal to c transpose minus l transpose w and w transpose w is equal to d plus d transpose. Let us look at these three equations and think about it for a minute. So, what we are saying is the positive real term what it is saying is suppose you start off with a gs which is stable and you look at the state space representation which is a minimal representation which essentially is equivalent to saying a b is controllable and a c is observable then the real part of g j omega is greater than equal to 0 or in other words Nyquist plot lies in the first and the fourth quadrant if and only if there exist matrices p l and w of appropriate dimensions such that a which is a system matrix here a transpose p plus p a of course incidentally this matrix p is going to be a symmetric matrix. So, p is going to be a symmetric matrix and therefore a transpose p plus p a this whole thing is going to be symmetric and what we are saying is that this matrix is going to be minus l transpose l.  I mean it is guaranteed to be positive semi definite it could be positive definite if l had the full appropriate rank but it is guaranteed to be positive semi definite. So, what the first equation is saying is that there is some matrix symmetric matrix p such that a transpose p plus p a is negative semi definite.  The next equation connects p and l and w through b and c where b and c come from the state representation it says p times b is equal to c transpose minus l transpose w and this w is something that purely depends on d. So, if you d plus d transpose this is going to be a symmetric matrix and that symmetric matrix is exactly the same as w transpose w. So, the positive real lemma is something that holds only if you assume gs is stable. So, if you take away this assumption that means you do not assume gs is stable then this condition that the real part of g j omega is greater than equal to 0 if and only if these things well this does not hold anymore. Now, the point is that this p essentially defines the storage function. So, there is one more condition that I need to add which is there exist matrices p, l and w with p being positive definite. Now, if the condition gs is stable is put in then this p is positive definite but if this condition gs is stable is not put in then this p is not guaranteed to be positive definite. So, the positive real lemma says that if you take a gs which is stable and this is the state space representation it is in a minimal representation. So, a b is controllable, a c is observable then the real part of g j omega is greater than equal to 0 if and only if there exists matrices p which is a symmetric matrix and positive definite and two other matrices l and w appropriate dimensions such that this all this is true. So, p is a symmetric matrix and p is greater than 0 then all these equations are satisfied. What does all this mean? So, I have just stated a lemma called the positive real lemma but what does this finally mean? What this finally means is that you could think of the storage function for the system. So, the storage function E one could think of the storage function as x transpose px where p came from that positive from the earlier lemma. So, p is greater than 0 then you are talking about. So, if p is positive definite then you are talking about a storage function which is positive definite. So, now if you have the storage function and you look at dE dt dE dt is equal to x dot transpose px plus x transpose px dot for x dot you substitute a transpose b because you have the state equation saying x dot is ax plus bu.  I will write this in a more compact form x transpose u transpose and then I have this matrix here and then I have x and u and out here I would have a transpose p plus pa then I would have pb here, I would have b transpose p here and 0 here. So, this expression is the same as this. So, what we have got is an expression for dE dt by just using the state space equation and using that p that had appeared in the positive real lemma and I get this. Now, throughout we have been saying that the supply is given by u transpose y. So, a moment here you see I have taken the storage function to be x transpose px ideally this is a quadratic one would put a half here and so what would happen is there would be a half appearing in all these terms because of the half that I have put there. So, I will compensate for that by taking the supply to be 2 times u transpose y and you would see that this is just a play with constants it really does not matter all that much. Now, so the supply is 2 times u transpose y, but from the state space equations we know y is cx plus du. So, the supply which is u transpose y I write it in a symmetric form.  So, the supply turns out to be this expression here. Now, for passive systems we said supply minus the rate of change of energy this must be equal to dissipation, but this dissipation is of course going to be greater than equal to 0. Now, we found an expression for the supply. So, it is x transpose u transpose with this matrix so x u this vector you are using on either side of this matrix. So, I will just use this matrix and sort of suppress this x u. So, if I write down the supply matrix I get 0 c transpose c transpose d plus d transpose minus now d edt again I had a similar expression using x transpose and u transpose which was this and so if d edt is this particular expression. So, I can subtract this expression from the earlier expression.  So, this whole matrix put together pre multiplied by x transpose u transpose and post multiplied by x u this must be so what I have written down here is supply minus d edt. So, this whole thing must be equal to dissipated energy and so this matrix must be a positive definite matrix is what we should have if the given system was passive. Now, if you put this together then the resulting matrix that you will have the first entry is going to be minus a transpose p minus p a let me write it down minus a transpose minus p a then here I will have c transpose minus pb here I will have c transpose now both of them are not c transpose one of them at the bottom minus c. So, the mistake c minus b transpose p and here I have d plus d transpose. So, this particular matrix is the same as this.  So, the negative of this is l transpose l. So, for this I could write down l transpose l. Now, if I look at the second equation it says c transpose minus pb is l transpose w. So, for c transpose minus pb I could write down l transpose w and this is just the transpose of that. So, this is w transpose l and then the last equation tells us w transpose w is d plus d transpose. So, this I could write as w transpose w but what this matrix is this is nothing but l transpose w transpose multiplying l w and this is certainly greater than equal to 0 because this is essentially like squaring a matrix. So, what we are essentially saying is, so if you go back to the positive real lemma, when you are saying gs is stable and this is true then it says that there exists all these matrices p which is a symmetric matrix greater than 0 such that these conditions and the other two matrices l and w such that all these conditions are satisfied. Now, what I have just shown here is if you start by considering e the storage function if you start by considering the storage function to be x transpose px where p is obtained from that positive real lemma then and if you think of the supply as u transpose y then when you take supply minus the rate of change of storage then you end up getting this equation and you manipulate that you get that that thing is going to be greater than equal to 0. So, what we have essentially shown is that in the positive real lemma if all these conditions hold then if all these conditions hold then you have passivity. But as far as this lemma is concerned we have not shown either way what we have shown is if these conditions are satisfied then the system is passive. So, now I seem to be out of time for this lecture and so in the next class I would show the positive real lemma and the implication the necessity and the sufficiency I would prove in the next class.


So here we are back with another episode of our series. We are currently on the series, Cedar Point Conspiracy Theories. The last two have been a great success. A lot of people like it, so we're obviously gonna continue it. And in today's episode, as you already know, we're gonna discuss Cedar Point BNM Strata. So the Strata Coaster is something that has been talked about actually quite some bit, especially in recent years with this whole, you know, rumor going around that magnum's gonna be removed, la-de-da. You already know my thoughts on the magnum removal from my previous conspiracy theory video. I just don't see it happening, but we're definitely gonna touch on the BNM Strata. For those of you that are new to this series, I discuss both sides, so I discuss why it could happen, why it won't happen, and then I give my personal thoughts on the matter. These are not my reflection of what I think is going to happen at the park. So whenever you see a title like BNM Strata or magnum removal, it is not my thoughts. It's just the topic of discussion for the series. I do wanna start off this video though with I guess asking you guys, if you could share this video and get this series out there, more people watching, we are about to hit our one millionth view today. So that's a big day, big milestone for us. We are live streaming today at 8 p.m. to celebrate. So if you guys can help us out, share this video, get the message out there, get more people, subscribe to the channel. That would be awesome. The channel is growing rapidly thanks to you guys. I see your shares, how many people are sharing our videos and I couldn't be more thrilled. So thank you so much. So I do wanna start off the video with a reasons why the Strata coaster is coming to Cedar Point. This was really hard for me. So again, the concept of a BNM Strata is it will have a lift tail. This was really hard for me to come up with because I actually won't get into what I personally think just yet, but some feel it's old and outdated. And when I say that, we're referring to Magnum. So a lot of people refer to Magnum, actually not a lot of people. Some people refer to Magnum as old and outdated. I'm gonna change that word to some because I'm a firm believer that Magnum is actually super underrated and I love Magnum. So some people feel it is old and outdated and it's time to be replaced.  This is somewhat true. So with a lot of the back area that we see, and we're gonna touch on that in a little bit later on in the video, is there's a newly bulldozed plot of land where the hotel used to sit right in the back end of the peninsula. Magnum kind of blocks off this route that goes back there that could be used for expansion purposes for the water park or maybe for a bigger coaster or maybe they wanna put a GCI all the way back there. Who knows what's the plan for Cedar Point or Cedar Fair with that land. But there's definitely this area that Magnum blocks off. It kind of like drives like a line down the center or a little bit down the center of the water park and then into this newly bulldozed plot of land. And no one really knows what they're gonna do with that plot of land yet. So it'll be really interesting to see what's to come. Stratocasters with a chain lift would be the first of its kind and it would take us back to the days that Cedar Fair used to be the trailblazer for these first of a kinds coasters that push the limits and all that. I would love to go back to those days where Cedar Point announces that coaster and you know it's gonna be the first of a kind or the world record breaker. We're still kind of in those days but it's definitely simmered down a little bit. So they don't go for pushing the limits to an extreme. Steel Vengeance was definitely going for the extreme. Some could argue Val Raven was as well and Gatekeeper was as well. But I'm talking about the days where Millennium Force and Magnum first out of this world attractions. So definitely wanna go back to those routes and a B&M Stratocaster with a lift hill would be going back to those routes in a way. So let's say the rumors of a Kings Island 2020 giga are true. Cedar Point would need another new massive steel roller coaster to compete with that in the same state. So I mean, to be honest, that was a very fair argument for me. When I heard that argument I was like, that's pretty fair. I too would think the same thing if Kings Island does get a giga coaster. I do think Cedar Point will need that new massive steel coaster again. So this is that argument that kind of started to get my brain ticking a little bit. So not trying to foreshadow a little bit to the end of the video, but that was definitely an argument that got me thinking. And again, it could reroute a lot of passage for the water park and all that. So it was again, it was hard to come up with arguments in favor of the B&M Stratocaster coming to Cedar Point. I'm gonna get into the reasons why not now. Again, this was a lot easier not to truly foreshadow, but again, from my personal opinion and just from current evidence, Magnum is not being removed. It's not, it's time to go. It's a very popular attraction and it's very unerated and amazing hyper coaster in my opinion. I just don't see it. It's not its time yet. A Stratocaster would require way too much land and without Magnum's removal, there isn't many locations that Stratocaster could fit. There are absolutely no signs of Magnum's removal at this current time. And that would mean there's no reason to believe we're looking at a Stratocaster coming anytime soon to Cedar Point. With the coasters we're also seeing, and this was kind of my argument, with the coasters we're currently seeing being built at Cedar Fair and Cedar Point and other parks and all that, going out on a limb and building this massive B&M Stratocaster, it just doesn't seem like the right time. We're not seeing any evidence of Cedar Fair back in their roots, building these massive steel coasters that blow people out of the water. And just from a marketing standpoint, it wouldn't make sense to jump right onto that out of nowhere. You wanna save these massive needed expansions and ability to build these massive coasters for a time of need and right now it's not quite the right time. I do wanna stress as well that there's two other coaster models I can see being built first, such as a GCI wooden coaster or a flying coaster before we see a strata with a lift hill. There's just so much possibilities with those two coaster models before we even need to consider a strata lift hill coaster. So in my opinions, this is really a tricky one to be honest. It's very difficult to predict at the current time as I don't see it in the coming years. But as soon as we see any signs of Magnum being removed, I'm probably gonna be one of the first people to jump on the B&M strata lift hill bandwagon. For a couple of reasons, I just see Cedar Point down the road needing these massive investments to compete with parks close to them or even at a distance. It almost seems like the whole coaster wars has started again. It's a very interesting topic of discussion because we see parks like Six Legs Magic Mountain, Six Legs Great Adventure having that possibility of restarting those coaster wars. We're hearing Six Legs Great Adventure might get a coaster in 2020. Six Legs Magic Mountain is back in the game with building these really awesome massive coasters and Cedar Point is gonna have to follow suit. Especially since Cedar Fair seems to be cannibalizing Cedar Point's records and building record coasters of the same models at their parks around the world. I say around the world, I mean in North America, like Canada's Wonderland, Carolins, Kings Island, et cetera, they seem to be taking their own records. But as soon as we see Magnum being removed or any signs of that, I will definitely be the first one on that bandwagon. They're not gonna replace Magnum with anything else but an exceptionally large world record steel coaster in my opinion or something that would bring people in. Again, I do personally think there are better options out there currently like a GCI wooden coaster or a flying coaster from BNM. There's world records to be taken there before they start going into that world record steel coaster, sit down steel coaster category again. I just feel like a BNM flyer is one of their best options to go down. There's a lot of world records they can take there. Even a GCI Woody, lots of records to be taken there before they go down the route of the strata with the lift hill. I would like to see Cedar Fair going after records again as I stated earlier in an aggressive manner and pushing the limits, especially at Cedar Point. I missed this whole era where they did that. Anyways, what do you guys think about the strata coaster coming to Cedar Point and what year do you think you could see a strata coaster coming to Cedar Point? I wanna hear from you down below. So comment down below what you think. Is this a fail or is it a win? Definitely comment down below. Hope you guys liked this video. Give it a like, subscribe if you haven't and share for others to enjoy. Thanks for watching guys and as usual, have a good one, bye.


A week before, two weeks before again. I see. Mr. Newton, you're exactly the reason for it. Oh, that's great. All right, good afternoon. We're going to begin our next talk, which is, you can see, this title is Sinif. I'm missing role in Padraal's game. And, of course, our president here is Deepak Cohen, who is an associate manager in quality engineering as is stated on this slide. So, how would you go further ado? All right. Am I audible? At the back? Okay. So, my name is Deepak. I'm an QE, basically. And I started in 2007. This was the year when the global economic recession also started, incidentally. And the Selenium and the WebDriver projects also merged, which would then go on to become the de facto web testing standard. So, I did five years in PTC, which is paramedic technology. And before coming to Boston, I was not aware that PTCs had quartered 19 miles from here. And after that, I did six years in Red Hat. And I've been doing the same thing for last 11 years, like accepting user stories, writing automated test cases, and finding bugs. So, you will say it is a monotonous job, right? But if you have an eye for it, it throws a bit of nuances and challenges every day. All right. Anyone in this room whose responsibility is the software quality? All right. So, there are a couple of people who fell in the trap. So, this was already discussed in one of the earlier sessions that quality is everyone's responsibility. And the agile recipe. So, my talk is an agile recipe. So, it is only fair that I give you the disclaimer that the most important ingredient of any agile recipe is the people which practice that success recipe, right? So, you cannot copy a successful agile recipe and paste it on a different team and expect similar results. So, it can either do really well, better than this other team, or fail really bad. All right. So, let's start with the heartbreaking story. So, has anyone seen this progress bar on a web page? GitLab has it. Okay. So, it was back four years ago. I was working on a user story. And it was a ticket management tool. Single page web app, ticket management tool which had, let's say, hundreds of fields. And out of those hundreds of fields, two were the fields which used to be pulled regularly because we had to show users the correct data. A very updated data. So, what we used to do till that time was we used to discreetly update those two fields by pulling, making two network calls in the backend without telling the user. So, in that sprint, there came an enhancement request that you need to give users a visual clue that you are fetching the fresh data for those two particular fields. So, my developer friend used this JavaScript library. I really liked it because it was on GitLab. It was on my favorite e-commerce site. So, I thought it was cool. So, as a QE, I tested on different browsers because JavaScript, and then I did regression tests as well. And one Friday morning, eastern time, and unfortunately the Friday evening, India time, we released it. And I had this habit, like teenagers, when they put their cute selfies on Facebook or Instagram, they refresh the feed to see how many likes. So, after every release, I had this habit of, you know, monitoring emails, IRC, as well as the bugzilla feed to see whether there is some backlash or not. Till 30 minutes, there was nothing. And after 30 minutes, there was a huge outrage. These are not the actual flippings. I just made them. So, there was a huge outrage. So, everyone said that this is a usability disaster. This change, this particular loader is distracting us from working. And if we don't work on cases, Red Hat loses business. So, we quickly reverted the change and to bring back the saneness in the system. And then we had a retro, right? Like every team, we had a retro. And out of the retro, everyone said that this happens. We could not gauge the user behavior, right? We thought it was a good way of implementing this change, but we could not. So, we actually brushed it under the carpet. But then I did a retro with myself. I'll explain in another slide that the retro which you do with your inner self is the best retro ever. So, this was the struggle. So, this is the user. Support engineers in our case. And this is the QE and this is the developer. If you look at these three categories of people, which two are more likely to go for a drink together?  Like QA and developer, right? Because they have that team bond proximity. And because of that proximity, which is a psychological thing, right? You cannot change it. Because of that proximity, what QE does normally in agile teams is they test the change. They don't test why did the developer implement that code change, right? So, very existential question. But QEs mostly fail to do that. And more so in today's time when we don't have traditional QEs, right? Every QE is also a developer of some different kind. They are writing code day in and day out, right?  So, now you have three ways of breaking that code, which you have already seen. But it's not a black box to you now. So, there were hundred other ways of breaking that code, which you will miss now. Then we thought about why don't we do one thing? Why don't we bring fresher perspective into the QE thing? So, same work stream, we bought another QE, right? But without making any capacity changes. So, there was user story one, there was user story two. And there was first QE and primary QE and secondary QE. So, primary QE will work on user story one for 50% of his time and on user story two for 50% of his time. And the same thing secondary QE will do. So, because no two people think alike, I haven't made it up, it is neuroscience. Our mind is connected like our fingerprints, it's different. So, different people perceive things differently. So, if you look at crowd sourcing testing platforms, which have, you know, boomed up recently, they exploit this thing. So, they'll take a website and throw it to 500 testers all over the globe. So, we thought that this will at least make some improvement in our process. It did. But there was still a gap because to work in this system, both the QEs needed to attend all scrum ceremonies like daily stand-up planning, retro everything. And the proximity challenge which the primary QE earlier had, the same thing happened with the secondary QE as well. Then we came up with a new thing called Cineq. Cineq is someone who is not part of this work stream, a completely different person of maybe a different project or someone else on the bay. So, what does Cineq do? So, how do you, the first thing is how do you find a Cineq? So, these are the qualities of a Cineq. Cineq should not belong to your work stream or project, which means that he is shielded from the project-related discussions, right? The Cineq should be naturally a vocal and SRT person. So, we don't need to make any effort on finding these people in red hat, right? And the third and most important thing, he should be willing to help. Again, in red hat, you will find, because people contribute to different projects. So, you will find Cineqs. And then, if you don't find, then you have to incentivize. Right? Now, what does a Cineq do? Cineq gives a very fresh and mostly end-user perspective to your work, because he's not seen the code, right? He's not been part of planning or grooming or scrum. So, he is looking at your changes as a user. And Cineq is your accountability. And if we go back to this line, what we have to do is, we have to nudge this person from here to slightly here, right? And Cineq does that. He nudges the primary, secondary QE towards the building the right product side. Now, the take-aways from this talk. So, if you look at what happened after that incident, that usability incident, first we tried to introduce a secondary tester, right? Then we identified the gaps. Then we tried to implement a Cineq. So, we were constantly improving, finding gaps and improving the system, which is the essence of an agile team. And then, again, the thing which I said earlier, best retrospectives are the ones which you do with your NSL, right? Because the actual retrospectives are very formal. The third thing which you can do is, you can sign up a Cineq. You can find a person in your bay who is not part of your project and ask him if he can give 30 minutes per week to you and see if it works for you. As I said, this is a recipe that can work for you. It can work better for you than it works for us. Because in our team, we have a UI work stream, a mid-tier work stream, a services work stream. So, the QE working in UI work stream automatically become natural cynics of, because they are the consumers of the service layer, right? They become natural cynics of the service layer work stream. So, what you can do is you can find a Cineq, a very assertive and vocal person, and try to sign him up for your project and some physical takeaways. So, if you look at this Tiffin carrying duty bag, I have bought this, three of them from the mountains of Kashmir in the north of India. So, I actually want the feedback for this. So, for that, I am incentivizing. That's a nice bag. So... Why aren't you taking off the Cineq? Sorry? Are you taking the process by buying this in its affections? Maybe. But right now, I just want feedback for this talk. So, whoever uses this hashtag, you can take the photo as well. So, whoever uses this hashtag in the next 30 minutes and provides a tweet as a feedback. And because I have bought them with my hard-earned money, so I'll choose the best it reads and I'll give away these bags. All right. Any questions? Great talk. I really enjoyed the Cineq as part of the team and that aspect to it. But I noticed that there was a bit of a similarity between the secondary QA and the Cineq because you're already pulling in an engineer from some other... There is no similarity between Cineq and secondary QA. Secondary QA is part of your work stream. So, he has to attend your scrum ceremonies. But doesn't the Cineq also have to... No. So, for Cineq, you have to... The only interface between your project and Cineq is the primary QA. So, just like code review, you write code, you get your code reviewed from your body developer, right? So, let's say all the stuff which was developed came on the QA environment. Now I have to test it. But before testing, I demo it to a Cineq to get a fresher perspective. 30 minutes for per-spirit. It's not much to ask for. So, my secondary question. So, if QA chooses a single Cineq and like frequently demos with them, after some point, they're going to become buddies. And so, they're going to have to find a new Cineq. And so, maybe Redhead won't have this problem. But at smaller companies, they might have trouble finding enough Cineqs to... See, if primary QA and Cineq become buddies, that's okay. That won't make any difference, right? Because it does not put any bias in Cineq's mind towards the work which developers are doing, right? If they're buddies, I think there's going to be a little bit of a bias. But he's a QA, right? The job of QA was initially to start with to break the code, right? But then we went into simply rubber stamping the code. So, we need... See, if you go to GIM, right? The most common example of accountability partner is the weight loss thing, right? You start with weight loss. You make a new resolution, you start with weight loss. And over a period of time, let's say by 3rd January, you stop going to GIM, right? But if there are two people who are each other's accountability partners, then there are chances that this weight loss resolution will go till March or maybe mid of April. Thank you. Any other questions? Feedback? Me? You need a professional sign? Yeah. I'm a hire. All right. Thank you, everyone. Thank you for your time. Don't forget about the bags. I don't want to take them back because I have done shopping from Boston. So, everybody probably remembers, we're going to be men's job for the afternoon, the closing afternoon.  Okay. So, you have to find a time.


Welcome. Now we'll focus on the influence of citizens in co-creating policies and politics for sustainable cities. First, we'll look at direct participation. Next, I discuss the participation letter to assess citizens' influence in co-creation. Finally, I will give three examples of direct participation. When you think of citizens in city politics, you may think of voting in elections and referenda, or maybe about protest and large-skilled demonstrations. But citizens are engaged in many more ways. For example, they tweet to oppose to a new policy, they deliberate about the future of the city, or they start a community garden. Besides formal and organized political participation, citizens influence and co-create sustainability politics in many ways. Direct participation is of special relevance. This form of co-creation refers to the active and direct involvement of citizens in decision making. By actively including citizens and their voices, knowledge and ideas, city politics may become more effective and efficient, better informed and more democratic. These forms of direct citizen participation are often government-led, but companies and NGOs can also adopt the role of organizing or supporting direct citizen participation. In 1969, Arnstein famously developed a letter of citizen participation.  At the top of the letter, citizens have real influence. They are in control, partner up with other stakeholders, or have delegated power. This is when co-creation takes place. When we move down the ladder, we go from tokenism or lip service to non-participation. Note that according to Arnstein, consultation and informing are forms of non-participation. In some cities across the world, however, these steps would be considered important to increase the influence of citizens. Let's have a look at some examples. The first example is a public hearing that can be organized by local town councils to inform citizens about a decision and to let them bring in critique and experiences before a policy is issued. In the photo, you see a public hearing in Seattle about the city budget. The second example is a form of more influential participation. This is the example of participatory budgeting. It has gotten famous through experiences in the city of Porto Alegro and Belo Horizonte in Brazil. And it's now applied all over the world. For example, in New York City, local people decide on where some of the government money is spent. The last example is deliberative polling, which is developed by James Fishkin, Professor at Stanford University. Deliberative polling consists of three steps. A baseline opinion poll among randomly selected participants. A week of discussion and deliberation among a selection of citizens and experts. And then a final poll with similar questions as the first one. Deliberative polling often results in significant changes in public opinion and in city politics. An example is deliberative polling in the Tamale metropolitan area in Ghana, West Africa. Through the deliberative polling process, citizens became more informed about food and water security. They also prioritized, for example, a rainwater harvesting system in schools as an intervention. These examples demonstrate that direct participation in city politics is an important and widespread form of co-creation. The promises of direct participation are many, more engaged citizens, empowered citizens, and better informed citizens. Better informed policies have more effective policies and ultimately more legitimate and democratic city politics. While recognizing the potential benefits of different forms of co-creating city politics, I conclude with a warning. If citizen participation is not taken seriously by governments and other stakeholders, citizens might lose trust in their city government. When co-creation fails, this affects democratic legitimacy and may harm future decision making.


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