Hello, hello Hey Ken to the many unanswered emails that I have back to you or or to your latest one Yes, is the The answer that there are some of the things that we're gonna talk about today It's the it has always been the intention that some of that would go Into academic publication Awesome and if there's an If part of that means collaborating with you all the better It doesn't but I definitely can collaborate if you want no problem But it can it can be I was just he was just asking I'm doing a proposal from my like thesis I did 20 something years ago now, right and he wanted to Update it and submit it and he asked if I knew anyone else that interesting thing is going on in the space And I thought of you so So you definitely don't need me to collaborate on it and you can go in with you know, you and you know Whoever you're working with names on it for sure Oh nice. Okay. Yeah, you you thought of the first You thought of what what nerds do you know Great, thanks. Thanks. I know I know lots of nerds at least you should feel like That's all right because I I have plenty of nerds in my background. I can reach out to you I picked you above them all Wait, were you just we're just digging that hole deeper I felt bad about the yellow snow you were drinking, you know, so I felt like I reach out and give you give you an olive branch Yeah, no moving on moving on Very good We've got the folks that are on the phone if if you've got access to the doc, please drop your name in Record your attendance We've got maybe one more minute before we Get going in this minute It's a great time to add agenda items to the bottom of the list I've actually seen Daniel here is great Daniel. Welcome. Hello speaking of of unanswered emails I'm gonna have an awkward moment here in about 10 minutes. I think I'm Really? Yeah, good to meet you. No worries. Oh, very good. Okay, Danny if I if I may Daniel if I if I may add a Conversation on Submariner as a as a topic if that's how if that's helpful or wanted today, but if not then You know, feel free to take it off. Okay. Actually, we'll see for a few seconds there. Oh You know, I'm dropping on Submariner in as a as a topic Assuming that that's okay, but okay Yeah, we My plan for today was just to say hello and then try to figure out a time to give a presentation I wasn't planning on doing the presentation today. That's okay Sounds good Thanks Nice nice to have you Daniel Daniel since we're shooting the breeze for just the the briefest of moments Anybody else here with you Let me just check the participants. I added it to our community calendar, but no, I don't see any other Submariner people here today Okay, so someone's got to lead the way. I get it Yeah, I'm trying to kind of help with our CNCF Effort been pushing that for a while now Just hurting sheep Yeah, very good. Well, we're folks were we're about six after let's get going if we could It's a couple of you whose names are relative maybe perhaps fresh to me, which is some super encouraged to see Anita here As well as Daniel and then we've got some some familiar names on the call as well Um, this is what I'm about to do is a slightly atypical for most of the CNCF calls that I've that I see and that I participate in But I like to do it on this call anyway, and if it makes anyone feel uncomfortable Don't don't sweat it, but I wanted to so Daniel and I just had a brief interaction Daniel. That was pleasant Hopefully you feel encouraged and welcome. I thought yes. Thank you. Good. Good. Good I'm Anita. Um, I figured it'd be nice to say hi or to let you say hi to everyone. And um, yeah. Hi, can you guys hear me? Yeah. So hi, my name is Anita. Um, I'm actually just subbing in a bit for one of my colleagues who comes here more regularly Christopher Hansen. He's sleeping because he's teaching an India time class now, but um We're both from ArcSum. We're a cloud native training consulting firm and We just like to stay on top things CNCF and Always great to observe and see what's going on in the space. So hi everyone Oh, hello Very good. Very good. Um Thanks for joining. Yeah and Folks, I don't I don't say this enough. Um, ken lets me ramble on and give you know, say bad jokes and that kind of a thing But um, so so ken ellens and and myself are um here as co-chairs of the SIG network. Um, just to familiarize everybody a little bit we have um SIG network it has Trying to think of not very strong language, but um It's the home base for you know, any number of network and traffic and protocol related projects that are within the CNCF And our order of business on those um, it tends to be fairly light and so um, because we have such a strong set of um, sub work streams happening in the CNC in the service mesh working group We've been using this time, uh To advance those initiatives. So we've been spending a lot of time on those So as we get into the topics we'll just to help I don't know that that clarification is totally necessary I think that the the reason I bring it up is because we'll end up speaking about a couple of projects in specific for quite some time And that's not because we don't want to do justice to other projects. It's because It's because we have the time so we so we do it so So if I hopefully that wasn't confusing But so the first couple of items um that we have for SIG network. Um, is just is just a reminder that um emissary ingress or the project that's formerly known as ambassador From ambassador labs from I think formally data wire It's proposed for incubation. It's been proposed for a while now. It's out for public review So if you have the they I know that they appreciate um supportive votes and feedback otherwise So everyone here is welcome to Um go make a comment or go go show support Another thing that was relevant um not to SIG network But to all of the SIGs is that and maybe particularly to SIG network actually now that I think of it is there's a popular kubernetes working group or SIG called SIG network Sound familiar? Yes. Sound confusing Yes, um Kubernetes SIG network is you know focused and concerned with networking within that project um So the two are distinct, but so there's a proposal out right now to Rename the cncf SIGs to cncf tags technical advisory groups That's of interest to people um, Daniel, we actually Happen upon the topic of Submariner fairly fairly quickly Daniel for those that might not be familiar with with the project. Did you mind I'm giving Just letting people know kind of high level what the project is about and we'll put a link to it so that people can Yeah, sure Uh, so just in a few seconds. It's a multi-cluster networking project Uh, we've been working with the multi-cluster networking so again kubernetes following really closely their cap process Implementing multi-cluster networking and service discovery right behind them basically um It's just a healthy open source project that we're open to get into this cncf as well It's kind of the angle that I'm here for um Yeah, happy to talk about other details that people have questions But we'll give a longer presentation with all kinds of details there and Daniel, um the canonical link to the project or the No Submariner.io I can add it to the central submariner.io and then there's a github that Is similarly named Very good Nice good It's been on the been on the radar for a while Or I mean before the even the interactions on here just um I take her for my part I take a note of the project is interesting Cool. Yeah, I thought you found this I think we met very very briefly or I saw you at least at the last in-person kubecon And then we've been working during the pandemic a lot our timing started basically right before the pandemic This one the project ramped up. So Gotcha. Okay. Okay Boy, that seems like forever ago that I actually saw another human Yeah Very good. So then there's a few topics within the service mesh working group um if you're you know, I recommend folks to Peruse the slides here, which talk about I think about five different initiatives within the working group And my hope is that we'll talk about two in depth today Because this initiative the arms right because the working group does have a number of sub working groups And much to to chat through and and things to execute on there's a There's the cncf sig network mailing list Which I believe is The url all the way up to here cncf sig network. There's a um A separate mailing list a sub mailing list if you will for the service mesh working group uh, so that Everyone isn't being Everyone who's focused on c and i for example or on gnats or something isn't being bothered with a bunch of service mesh specific stuff Or to the extent that they want to be that they would they would sign up So please, you know, if you're not signed up on that list and you find what we're talking about today Interesting. Go sign up tell your friends uh, two of the initiatives to cover today one is an update on get nighthawk I'm going to introduce people to nighthawk who aren't as familiar Of which there may be a couple nighthawk is Well, it's a well simply like simply say over Overtly simply stated. It's a load generator That doesn't do the project justice It's a it's a performance. It does performance characterization of layer seven of layer seven traffic for grpc for htp for for htp2 for Has had a lot of features and There's been an open source initiative to help get nighthawk into the hands of many And into one of the other projects that we That we talk about the meshery project So there's a few representatives here today Abhishek was it is it you that wanted to give an update on progress with respect to We continue Yeah, that's right Uh, yeah, thanks Lee probably not uh, so I just want to give a quick progress update on What we had where we had left last meeting um So at this she was in one second So the screen visible it is all right, so This particular documentation is being used to sort of get the track track the design spec and updates and the ongoing process of This particular project will get nighthawk last time when we When we had this meeting we discussed about the The area of concentration on what that what are the next steps that we're going to take On regarding this project So we discussed a couple of items on the ci process how we're going to publish Build the artifacts and publish nighthawk releases on different versions so I didn't put up a design spec about it Over somewhere over here mentioning some of the Key features like the artifact conventions and One second Yeah, basically the whole whole design spec ideas have been updated in this portion So for someone who's not checked it out yet, they can go over here to look at it So right now we've we've managed to Take a couple of steps ahead for on the ci process basically We've got a repository where We are currently building a custom ci For for publishing artifacts on the nighthawk On different distributions of nighthawk bindings so So yeah, like basically this The progress is on that we created a custom Action, yeah, this basically is the definition of the action which takes in Uh, certain parameters like the repository to publish to version of the nighthawk to be released Uh, the operating system architecture based on every different parameter that we are going to Release these different versions And then we we've got also the ci setup ready to be published and right now we We've added support for only two of the operating systems which are one two and macOS So these are the two workflows that have been established now but ongoing Maybe hopefully the next meeting they'll be So yeah, like that that's basically more or less the update on On the ongoing task of get nighthawks Does someone have any questions? Abhishek your voice cut out there right at the end where you were saying that's kind of that's the progress that's been completed and next time we might expect And then and then you cut out. Oh, okay. I'm sorry for that So whatever things that next time we meet uh, we might cover two more distros which would be Fedora that is red hat and also windows We'll cover for windows distributions good Any if there's any along with that Vinayak you've been Working with a few different contributors, but have been Busy behind actually, I think there's a video of you being busy behind the scenes building out the The project website Do you I'm gonna put you on the spot. I Do you uh Have an update there that you'd like to share Okay, so basically the get nighthawk website was so far Meant to be like a single page website to represent the get nighthawk So far we have covered Shall I share my screen? Sure, please Is my screen visible? It is Okay, uh, so basically, uh, this is the site that we have been working on for Get nighthawk and So far we have achieved all this Uh on the site and we plan on to I think implemented dog's collection for this website and customer review section in the future and I also a couple of more things are on the list for example a video section to Demonst demonstrate some of the things and resources for get nighthawk And example implementations Other than this, uh, we are currently Looking Currently making a decision on what the logo for get nighthawk is supposed to be We have a few drafts of it ready And currently doing a informal vote on it There's a link to those draft logos inside of the meeting minutes so So for anyone who has comments or who has A design that they think should be the be the design that represents Get nighthawk, please Please comment Good. I was hopeful that There are a couple of other Project maintainers that said they couldn't make it today But they have been responding asynchronously one of them in particular Really avoids any synchronous communication at all costs so um But anyway, please to see the engagement. Please to see the support from um nighthawk maintainers so Any questions or comments on get nighthawk For obeshack for veneath urban ag As we go to transition to the next topic. I'll I'll say this if um If nighthawk is somewhat unfamiliar to you um There's a couple of really neat things that that load generator is capable of that Is part of the genesis or part of the logic and the genesis behind get nighthawk itself The world the the rest of the world needs to get their hands on it. There's some Interesting ways to characterize performance so Speaking of performance characterization the next topic is service mesh performance And sumku is here with us. Perfect Sumku, there's a couple of folks that that I'm going to put you on the spot as well This is entirely. I don't know that this is fair or not But there's some of the folks that are on the call like blake who've been around the project for a long time And others just coming to to learn what it is do you Do you mind doing a practice introduction of what the project is? Yeah, definitely put me on the spot That's good That's good. So we've been discussing about smp last couple of times I guess the idea where we the discussion came into the point that There are quite a few load generators like like we mentioned and and also What I found running some benchmarks on service mesh type applications that there's some gaps with respect to how performance measurement could be done between lately Tuning versus layer seven tunic with respect to load generators. So in general the idea is you know, so we need a place where where we could discuss some of the methodology standards or Features of how performance benchmarking should be done for service mesh And Discussing with lee we found smp is a good place where we could collaborate and build on here and To the point that this could be a sandbox project within cncf So from that perspective smp provides the The right constructs with respect to where it is going one in terms of automated deployment For example meshry using meshry, but the main thing is it does provide integration of different load generator tools versus different service meshes along with it. So from that sense SMB Can be a place where we could discuss and build on That's the part what I've seen so far You can you can fill in the rest Yeah See it's all down like that Zero prep zero warning. It's all downhill from there. Like you'll hear That was fantastic to Try to add a little more flavor to to what sunko just said is that If if you're in that the meeting minutes and you take a quick look at The service mesh working group charter Uh, well, or you can look at the charter or I guess the slides maybe have it a little more crisply um I can't you know, for my part, I can't tell you how many times either I've been directly asked or I've heard people ask um What's the overhead of a mesh like you know, what how much is this going to cost me and how do I characterize that? How do as I go to you know, use it more and more How do I how do I make sure that? You know, I've got an ongoing analysis or an ongoing Hand on what that is Is did I make the right selection here in terms of technologies? How do these things compare? There's so many variables. And so, you know, there needed to be To sunko's point like a forum for You know vendor neutral forum for some of that discussion for the advancement of some of the studies that that I'm different groups different individuals have been doing and hopefully a common way of capturing and describing performance characteristics of um Well cloud native. Well in some respects cloud native workloads They could be running on a service mesh and they may not be You know much of the goal here is centric to what happens when they are but it's Like that's probably the first question that people You know after after they say hey, what's the overhead they say? Maybe in their minds one of the easiest ways to gauge that overhead is To measure, you know, here's how their app is running today. Here's how much that you know to characterize Its performance and its overhead off the mesh And what it looks like on the mesh and then they start to tune and tweak any number of knobs and and configurations and different service meshes and different versions and and Part of the part of trying to make this body of work useful is after having engaged with A couple of universities questions around What applications what cloud native workloads are Represented are you know good ones to study and use and disseminate knowledge on Which ones are representative of you know The most common workloads that others would have So just even the topic of what's what are good sample apps? Which ones are available? Where are they available from? Cornell had been there's a professor there that had worked on a few they've published a couple um, I think you know much like Okay, it was one one topic another kind of topic to add additional flavor to what Sunku was saying is that Well, there's any any number of configurations of not just the infrastructure the mesh what it's doing your applications How many nodes and clusters and all that all that stuff, but there's also A myriad of Um test configurations. So Is this a silk test a capacity test a stress test? Is this going on for 10 days? Does it go on for 10 minutes? You know, are you how how is the how, you know, there's all kinds of knobs to tweak on the load generators? How are they behaving different load generator different load generators measure differently?  You'll often hear about smp and to Sunku's point like the One of the first tools to implement this spec Meshory, you'll hear them talked about often together one because because these are both new and kind of Driven towards part of the same goal that part of their shared same goal is Is that of making it easy to repeat and run these tests but not necessarily against sample apps against users apps, you know against whatever those are and in whatever environment they have because Because it's all bespoke, you know to their environment. And so it's about empowering others to go off and answer these questions because I'm part of the goal and part of what I'm hopeful that You know, Sunku and the rest of you that are here will Commit to and and that we will collectively go off and do is You know defining working with these service mesh Groups or or those that aren't running on a mesh fine. Um, what are what are those? representative workloads what what I think while I while I personally consider almost any almost any Benchmark almost any load test that you want to define and run is is valid Some of them are not very useful because you know, no one's got that type of a configuration or or that load never hits their services in that way That's important where I'm, you know, excited that that Sunku and the rest of you are helping advance this because Those are things that that many of you know a lot better Yeah To add on to that what we see Especially in terms of blogs being published a lot of folks have done different Type of analysis and some performance numbers whether you see is still or on what All right, so there's some suggestions of what could be done, but then they need a place and a little bit more traction in terms of You know establishing a standard patterns like you mentioned Lee and also Our best practice is to see how best to characterize a mesh, you know What are the aspects to look for and that is not there today from what I see across and So how can we I guess the question is how can we you know Bring together that type of discussion to hear and ensure that you know, some of these work is represented across multiple meshes or Methodologies that being discussed online. How can we make it uniform? So that's easier to understand consume All right, so um, and one of the thing Lee discussed was having this project as a sandbox project in the RCNCF so that it's has much better visibility Make it easier to for folks to contribute and also participate Uh, but and just open to ideas as to see can it bring in Opinions as to what else we could do here. Yeah, everyone else is getting put on the spot today. This is this There's a you know, it's um Maybe I'll have one more comment and that is like soon could to your point. Um That that's one of those That's what I would expect and maybe Josh, I think you're the only one that maybe hasn't gotten put on the spot yet. I don't know but is When you're like, what is important? What are the important signals to measure? Yes, when I say signals, maybe some of you think about the four golden signals from the site reliability book So I guess I guess I probably am not the right person answer. It's just being I don't want to say new to the space but um Unfortunately, I'm usually on the side of implementing the technology that other folks go to do the performance for us um, I have some folks in the Company I worked at that I could probably ask what they're looking for and uh provide feedback that way but um Yeah, just off the top of my head. I don't really know I don't really know what I would recommend or throw out there Thank you, Josh. That that's yeah. Yes. Actually I'm from From my part, I would love to um for others to bear weight on that or to express opinion on um How important Latency is and the measure, you know the long tail latency and CQ maybe cq doesn't matter at all I will say just having had to troubleshoot some apps recently where we were running into capacity issues I'm finding out that actually one of the things we were setting cluster level is actually application level, but it's still Still played into it. I mean having that visibility um Cross not just things that we see Obviously the kubernetes are back playing which is where they thought the problem was but within a java app There's a memory and heat limitation that they were hitting up against causing the app to Keep crashing out and then they thought it was kubernetes limit causing it to then regenerate the pods, but being able to see it from the app level and then through the uh Through what what our settings are and actually I guess if No, I don't know is smp pulling in values for Limits that have been set at say the cluster level. So you you may be looking at performance, but you could also see what percentage Of your limits you're you're filling in so say I'm you know, I'm allocating only two gigs max memory to an application that's deployed Would that apps hitting you know, 80% of that limit not just saying hey, this is the performance you're getting out of it But also by the way, you're you're pushing really close to a boundary you may want to be aware of To increase that limit. I know that kind of visibility is very helpful for us ops folks Because we don't know when to go increase things until something Obviously keeps crashing and somebody calls us and we're like, oh, yeah, you keep hitting You know limit let us up that for you or whatever Right because you may be hitting the upper yeah, you may be hitting the upper bounds of Something that was either intentionally or maybe unintentionally configured, but it's a soft limit. That's um, that's specified and then causing you Causing you issues so like if you're not if you're unaware if you're unaware of the fact that there's a governor Or or a limit to find That then yeah, you may you may be off trouble right and I guess Yeah, we can obviously run all sorts of low generation tests and things and spec out and And figure out what we want to set things at then once you actually get into production It's usually a different beast and like you said those limits that are set Are sometimes blind to the application owners the developers They don't know what we've said at the operational level And so they're being called in trying to figure out why the app is not stable or whatever And really it's it's something else. So if there's a way to scrape that data together say when we know the app performs well Here and we see something you know going on. That's great. But at the same time it's your apps perform like it should You're just hitting these these boundaries that have been put on you And maybe that's something that's already in this application. I don't know enough about smp to know If it's if that's something that's already baked into the product I need to play with it a bit To understand what it can and can't do already This is this is a fantastic conversation Joshua like while like to answer your question very directly and sort of explicitly like while SMP doesn't capture the limit like a limit that's defined on a pod or Or across an interface today Maybe it should one But then two even if it didn't a long term that's still the a very healthy type of a conversation or type of Um information to disseminate You know through a project like this to to To let others know that they might be on a wild goose chase that like hey It you know some certain percentage of the time you're actually you're chasing down a performance issue that's actually Um, you actually configured your infrastructure to do that your your configuration is working you're being limited and it that's like Anyway that type of a disc like a that's a I'm gonna try to I'm I'm gonna make a note about consideration for that and asking folks They're on this call and and elsewhere to to comment on whether or not to include limits in The spec and then Even to the extent that they don't I'm josh to the extent that you keep coming here I might encourage you To like put put pen to paper on just a couple of the things that you just said because it's just Part of what the the charter of the project part of what we're trying to to do with s&p is Enable a standard way to measure things Enable people with a bunch of knowledge You know tests that have been run and results and things that they can see hopefully on Um on something of a regular cadence is to empower the service mesh projects themselves to measure themselves in a uniform way use And publish those results and in a way in which They're in hopefully a more fair way than they're being measured today because they're being measured today and And doing doing these measurements is pretty pretty difficult And there and those results being published and a lot of times they're not They're not it's not quite fair. It's either something's being compared and they're not apples to apples or Or it's not being compared but Someone forgot to turn debug off or something like someone forgot to actually tune their configuration. So Some of these projects are getting pie in the face when they shouldn't or you know egg in the eye and they shouldn't So when these tests are running are are they like you kind of set up? a traffic simulation of what you want to run through it or Are there like is there like a real world mix right because I I know what you're saying You know networking guy all the time We always see these specs of what throughput you can achieve But that's what like perfect sized frames going across the wire like they they they really They put the perfect workloads across them to show how fast those work But in a real world mix we see a lot more fragmentation or a lot more A lot, you know much smaller packets and many many more packets need to be handled things like that so Is there I guess how is that mix that mix being generated? And and then obviously you'd want to use that same workload against all your different Different items you're testing against so it's a fair A fair comparison right each group gets a set of their own tests They're going to obviously lean towards a test that makes them look good versus one then there may be not so good at Josh I that's such a what an excellent um topic that you just opened like like yes, of course and uh Like use of the service mesh really facilitate doing just that like At runtime of the tests Manipulating the mesh and telling the mesh to introduce some chaos Is one make one way of You know mixing up the test And another one is taking advantage of the load generator itself and its ability to to do just that its ability to inject faults or And and that's very much so squarely In the wheelhouse of what the spec should be considering for Do you know if it has like a Playback capability, so this this is actually use case that we're looking for today with a certain application That's in a an environment where it doesn't have The dev environment that we're practicing in doesn't have the same access to components that the production environment does so We what we want to do is just take like a packet capture or record the traffic And i've done this with other products on the market that you know sell very big iron appliances that can record A certain traffic simulation and then you go and play it back In your test environment to get get that there's that or am i going down like a whole rabbit trail It's not even a part of this product's capability or Or a test set that we want to look at Out Um So you're doing you're doing a beautiful you're doing a beautiful thing, which is almost exactly what synco had done last time which is we were talking about service talking about nighthawk and we were talking about Mechery And you know part of his question was hey, where's the where's the lining of these things? And you're actually broaching that same thing is like you're right that like hey the service As a specification What what is it capable of well, it's capable of capturing and characterizing In just in written form like in yaml form Capturing and characterizing Performance and how you're generating load what your environment is like what your configuration is like, you know Like doing that in a uniform way. So it so it's a specification that's Like unto its own it's kind of static in nature. It's sort of like, you know, here's a document this document is written in In accordance with this specification You can take this document this specification that describes all of my environment the way that I'm You know Generating a bunch of load real quickly and then backing off and then generate, you know, like that describes all those things I can exchange it with others and Have them run similar tests SMP itself isn't Isn't a capability, but it's a specification that other projects can implement And the first one to have implemented it is is this one meshery the use cases of like traffic recording traffic playback or like Or to generate test after test or like performance test after test is why Is why we're talking about meshery nighthawk and the spec So the spec being a document a standard way of capturing and characterizing all those concerns and considerations How long do I run the test for at what intensity? Using what protocol from what vector like how many load generators were there generating that load or how many playback generator not generators, but how many How many of those same load generators generators were playing back the messages And then to use the load generator to to do it the one that we're You know spending a lot of time on is is the load generator nighthawk And then to be able to to schedule it To capture the output of the tests to be able to compare the tests to share those tests Centralize them do studies over them to make it easy to repeat You know have a repeatable tooling to to measure these things is why we talk about meshery Um So yeah, so like what a beautiful you just sort of ran the gamut of the projects The whole stack. Okay. Yeah, that's kind of right now. That's where I'll I'll display my ignorance in this case is between these products knowing They're set so thank you for explaining that that helps a lot So with s and p we're talking the spec itself Like you said definition of what's going on or what to do and then the other products coming into play You know Getting that hot going in and actually doing the generation of those workloads and stuff like that and then meshery being that The current or one of the platforms that implemented the ability to actually let us Let us try it out in their platform That makes sense. Thank you. Thank you Look at that josh you I was just kidding about putting you on the spot and now you just explained the You just explained three of the projects and once Okay So so So the in the next 15 minutes kind of I think, you know, unless someone else has another topic, which I'll pause for The next topic was going to be um donating s and p to the cncf I'm the subsequent donation that I think that we I know there's been planned for a long time as the donation of meshery as well to the cncf So I'll pause before we talk about mechanics in terms of donation Is everybody question I'd send an email to the service mesh working group email list Not sure if anybody got it Outlook gave me a This email doesn't make this type of reply I got I ended up getting it. Yeah, I'm if that Okay, that's great. Yeah, I had to send it via the yeah the website. I wasn't able to send it via my email client So I'm not sure what the issue is but anyway, if that's working Find the way Yeah, and soon could you Yeah, yeah, exactly. So on I'll wait a second soon cool. I think I'm having the same problems I had sent a couple of emails one yesterday and one today and they don't Seem to be showing up Did did sunku did you get an email about the nighthawk logos by chance? Because it but when I send it via the my outlook it didn't go through Okay, I have to I'm glad that you brought this up because there's a couple that I've sent to the mailing list now that don't Okay, there was some network lag and I'm not sure if that was me here Everybody else. But yeah, I get your point I think I think it was on my side as well Okay Well fair enough. Well, there's um, you know by by number I think the majority of you that are on the call have had some amount of helping hand in smp or Or maybe just learning about it and have a potential vested interest Um, uh I think uh ken I think has already is already helping us get Um get there and get this thing submitted. It's a You know, here's an open opportunity for people to make their mark on an upcoming project This one has been socialized with the cncf toc I think more times than they probably cared it. I've heard about it. Um And it you know, it certainly strikes a chord because it's In it in it, you know, from my perspective it the cncf is a great home for an initiative like this because It needs to be in a a vendor neutral place. We're just trying trying to um, the goal here is Standardization and um information is to So so point is um part of the product the mechanics of donating the project is to fill in answer some questions These are the questions and the link to those questions is here here That doc was just created half an hour ago. So So is this kind of like a vision as to what the our goals of the project that we want to establish? once it's It's a sandbath project fine-stand, right Um, yeah, and well are this this particular doc is it's actually literally just a copy of The google form that is now used to submit cncf projects Okay, and and so I just copied and pasted the questions off the form into a google doc figuring What no better way than to invite others to participate than? Yeah, absolutely. Yeah I will go through that and um respond to it by tomorrow No, the deadline I mentioned is 23rd, I guess right so I want to review by before that and then Suga one of the things that you just said though about part of the charter and the vision for smp While we sort of reviewed Some some of that right now. I don't know that it is extraordinarily explicitly stated Prominently like it is it is explicitly stated in a few different places and some google docs over here And maybe in a blog post or something over here, but in my mind That could be made a little more Prominent or like hey, is it an ongoing goal? I would expect like once smp were to land into the cncf Is it an ongoing goal to to publish some benchmarks or is it a goal to devise what what the group considers to be worthy benchmarks things worthy of looking at Are there a couple of iot centric ones or a couple of uh, 5g centric ones or there are a couple of and uh Like to to your point about vision and scope. I think there's room for clarification Absolutely, I think as part of the proposal or the questionnaire we can mention that also we can also note Possibly write a blog along same lines. I know smp. We were talking about publishing a blog Whatever we are listing here. We could possibly summarize it in a blog and It goes with that and publish it in smp site Yes resoundingly yes That's an Yeah, internally we have to go through quite a few legal reviews or some reviews before You know, I can put in my name, but yeah, happy to kind of collaborate here and to find the procedure Within my company how how I can participate here But I think it's a no-brainer to kind of put it out there and smp sites. It's very clear For anyone who's looking at it So you may be a stronger a stronger person than me I have I have quit a large general large tech companies for less than Than having to suffer through that project process Yeah, I know So we go ahead, but yeah, no, there's some good blocks you have written already. So I think we can build on that Okay, hopefully hopefully all the rest of you feel like that's an invitation for you as well Please please if you're interested, please do same thing goes for get nighthawk and for meshery and there's There's there's actually a lot to nighthawk and there's there's even much much more to meshery much that hasn't been espoused and written down so Oh one one last item. Um, whoops it can I don't I don't know if If you mind me raising up this topic The um, josh was giving some fantastic perspective, you know from from is ken still on Oh, I think yeah, okay.  Good. Anyway, um, one of the things that ken was privately suggesting is that um If whether or not you know this or not, there's a there's another service mesh working group in the cncf and it's the is the end users Service mesh working group soliciting input um Excuse me input um from that collection of of individuals For my part, I think that that would be a wonderful thing to do to ask them if there are specific types of benchmarks or like to josh's point Do they see a particular pattern that really causes their um applications issues Do the is it is is much of their concern relegated to the mechanics of uh A canary rollout something that's a bit more You know that that's kind of specific to a surface mesh and what a surface mesh might be helping to facilitate Drop packets in between or redirect or the concerns around um a packet capture and a replay of that When you're replaying those same packets and yet You know if you're replaying If someone just submitted a payment to your service and you're replaying that in prod like Maybe you're charging them, you know more than you should So anyway, I totally digressed my the point was there's another um There's another working group to Socialize some of these questions with questions with and solicit feedback from So, um I'm sorry. Yeah, so good. Uh, no, uh, along this this topic. I'm surprised. There's another working group. Actually, I did not tell them So is uh, is there enough synergy that can be combined into two or is it total different charters? Oh, there's enough synergy. I would have been it is against my will that there are two or uh For my part and the reason that the in but actually there's a lot of logic as to why there are two It's I don't I don't actively For my part, I don't actively complain the concept the notion is Um, so that end users can I'm talk amongst themselves freely without harassment or suggestive comments from vendors It's kind of the um, is the Line of delineation Seems like it's more end user not just service mesh, but in general end user focus. There are a few other groups that are Uh in parallel to some of the technical working groups if I understand, right? Yeah, yeah, that's right. There's a whole you're right. There's a collection of um different Um, I yeah, I think they are called work. They are called working groups But there's an end user area and within there. There's a few different working groups on different topics that Get together and and yeah, you cannot work for or That's part of the divide is like consumers versus producers or Okay But that said what an opportunity lost not to um, have some of that exchange to be able to solicit um The complaints and provide those to those that are producing the tech or Invites for size. That's a good idea. Definitely And and they've warmed up to that now They've had a change of guard and with that a change of perspective So that's so it's another kind to do item there is to Make that connection On that topic as we go to wrap up here Anita. Um, it strikes me that you might be in You might end up in or interfacing with clients or or you consumers users as you guys go to um assist them In their use of some of this tech I'll plant a seed in your mind to think about it, you know, if This is an open forum for You know, some of that feedback about where people are really struggling Alrighty And Anita, you might have said something but you're on mute. Sorry about that double muted um I was going to say, uh, yeah, I'm not as much on the technical side But some of our consultants obviously they are and they would be um interested so I'm taking notes. That's part of what I'm in the meeting. Uh, so I'll Be sure to put a line and uh to talk about like callouts for if there's any kind of Specific issues or queries that might come up that might be relevant for you guys Please that would that be nice. It's it's yeah, otherwise we're just Making stuff up Working back. It was not fun. So it's totally understand. All right, anything else Okay Thank you all. Uh, same time in a couple of weeks. I'm Daniel Daniel, you're you're whether you're asking for it or not. We're penciling you in All right, it sounds good. We'll schedule some people to join us Okay, see you all in a couple weeks. Bye. See you guys


Kremlin blames Kiev for blowing up of Karkovka Dam. The Kremlin has stated that the dam at the Karkovka hydroelectric power plant was blown up by the Ukrainians. Dmitry Peskov, the press secretary of the president of the Russian Federation, said it in an interview with Russian media outlet RBC. We can already unequivocally state that this is a deliberate sabotage by the Ukrainian side. This sabotage could potentially cause very serious consequences for several tens of thousands of residents of the region, ecological consequences and consequences of a different nature which have yet to be established, he said. Peskov stated that Ukraine was pursuing the goal of depriving Crimea of water. He also rejected accusations against the Russian military. The water level in the reservoir is falling and, accordingly, the supply to the canal is reduced, dramatically reduced. It looks as if the sabotage is connected with the fact that having started large-scale offensive actions two days ago, now the Ukrainian armed forces are not achieving their goals. These offensive actions are faltering, he added. Russia's investigative committee has opened a criminal investigation into an act of terrorism following the destruction of the Karkovka HPP Dam and the flooding of the territories. History reports indicate that the Karkovka hydroelectric power plant was blown up by the 205th Separate Motor Rifle Brigade of the Russian Armed Forces.


Welcome back everyone. In today's lecture we are going to discuss what happens when a dynamic system undergoes pre-vipration. So in the previous lectures we have seen that when a structure subject to dynamic load then we learned how to set up the equation of motion. Now in subsequent classes including today we are going to looking up or we are going to be discussing some special cases that can be analytically solved okay and we are going to start with the simplest case of dynamic loading which would be pre-vipration in which case a structure is basically assigned some initial condition like displacement and velocity and it is allowed to let vibrate without any external force acting on it okay all right. So let us get started. Till the lectures that we have done so far we saw that how to set up basically the equation of motion of a system under action of an external force okay and we derived that the equation of motion can be written as f i plus f t plus f s and that should be equal to the applied force and for linear system we saw that we could write it as m u double dot then c u dot and then k u should be equal to p of t okay. So up to the last chapter our focus was to derive or to finally come up with an equation of motion which is of this form for a different type of system okay so we had different system under the action of external load and we saw that how to derive this equation of motion now what we are going to do we are going to study special cases of this equation of motion for different type of vibration okay now depending upon what is the external load and what my system comprise of we are going to deal each of we are going to discuss about each of these systems one by one and then see what are the application of those type of systems and then how do we actually or like you know how do we physically interpret those systems okay so if you look at these equation of this equation of motion we basically have three components okay now depending on whether we have a value of damping okay zero or non-zero and what is our force of excitation okay based on these two important parameters we are going to discuss different properties of a dynamic system okay so for example let me characterize what happens for each of these cases so in general we saw that we had equation of motion okay now we draw something like this then when damping is zero okay so when damping is zero we had three or let us say let us start with that when the applied force is equal to zero so Pt is equal to zero in this case then we will have what is something called as free vibration okay so this is free vibration and under this free vibration depending upon whether my system is as a zero or non-zero value of damping okay we can either have undamped free vibration or damped free vibration okay so again we are going to characterize between undamped free vibration or damped free vibration so remember that this was for Pt equal to applied force equal to zero this is c equal to zero okay and this is c not equal to zero okay so this is the one categorization one tree branch in the other part we have what we are going to discuss not a zero value of applied force but a non-zero value in that case we are going to discuss some specific cases for example what we are going to start with if we have non-zero value of the applied force we will have forced vibration okay and depending upon the nature of forcing function okay we are going to study where few specific cases and then few generalized cases so we can have like you know harmonic motion so when I say harmonic I mean something of you know I mean something similar something combination of sine and cos okay and then we could have a non-harmonic motion okay so we are going to say let us say yeah non-harmonic motions so we could have let us say so this one would be like you know something like sine cos etc okay non-harmonic could be like you know something like step functions or like you know pulse excitations or things like that and then we will have random excitation okay and random excitation we have let us say earthquake excitation or seismic excitation okay so depending upon what is the nature of the forcing function we are going to study all these topics and then of course like you know in each of these topics we are again going to study you know damped and undamped okay so again we'll have damped and undamped and we are also going to discuss that how we are actually going to obtain the response of those system for example if you have a harmonic excitation like it is feasible to obtain an analytical solution or a mathematical solution which is a closed form solution for non-harmonic cases if for very few specific cases we would be able to obtain analytical solutions okay for random excitation it is not possible the like you know because the excitation cannot be represented as a simple like you know I mean a combination of functions that are amenable for mathematical solution so in that case we are going to study how do we obtain solution using numerical methods okay so we are going to study that as well okay now today what we are going to do okay we are going to focus on this re-vibration okay what we are going to focus on this case today as re-vibration okay now as I said what do you mean by free vibration okay free vibration happens when you basically imparts an initial velocity or displacement to a system and let it vibrate without any action of external load okay so basically in short okay basically in short what we will have as pt equal to 0 all right so this is the condition for free vibration without any action of external load we let it vibrate freely okay and we will see that for this type of system we could have either undamped free vibration okay or we could have damped vibration and we are going to study both of these today okay now the question becomes that you know how do we impart or initiate free vibration okay so one of the ways to do that because we just said that there is no external force the question like in how does the motion start so we to start a free vibration we impart either initial displacement to the system okay so it would be either initial displacement of the system or initial velocity okay so initial displacement means u0 or initial velocity would mean u dot zero and like you know I mean you can see there are a lot of example for this type of system for example if you take a pendulum and then you lift it or if you provide initial angular displacement of let us say hit a knot all right and let it vibrate okay then it would go under the action of it would basically undergo free vibration okay so that is one example there are other examples as well for example initial velocity would be something you know I mean you take a hammer and then you hit something let us say an elastic system with that hammer okay and then that would be basically imparting initial velocity because in that case the hammer imparts lot of force in a very small amount of time it does not have time to react so it would not have initial displacement as such but because of the like you know large force in a short duration of time it would acquire initial velocity and we are going to discuss that like you know that is called impulse and how do we impart that okay so these are the two conditions through which we can initiate free vibration in a system all right now these type of system or these type of motion free vibration as I said because it is without action of any external load okay these type of system can be utilized or that this kind of motion can be utilized to obtain basically important parameters of a oscillatory motion okay for example so let me just write it here to obtain important parameters okay and two important parameters okay and we can we can do that experimentally so two important parameters are basically what is the and we are going to define that what is the natural frequency okay and what is the damping ratio okay so these two parameters can be obtained using the free vibration of a system okay so it is like you know it becomes very imperative that we obtain analytical solution for the free vibration of a system okay so the first thing that we are going to do in this chapter would be un-damped free vibration and then we are going to go to and discuss the damped free vibration okay so first thing we are going to discuss is undamped free vibration so remember this is a free vibration and this is undamped so free vibration means Pt is equal to 0 and damped means C is equal to 0 okay so basically our equation of motion becomes what if you substitute these two equation of motion I basically get this okay with of course we need as I said we need to have an initial condition otherwise if you solve this differential equation without an initial condition you would get a trivial solution okay so the initial condition a non-zero it need to be a non-zero initial condition either what should know sorry or what should be the values of u of 0 and u dot of 0 and one of them must be non-zero to initiate the free vibration okay so these two condition need to be utilized all right so what we are going to do first we are going to solve this system and obtain the analytical solution for u of t okay and then we are going to get into the physical interpretation of the response for the free vibration so solution to a second order linear homogeneous differential equation remember that we now do not have any term on the right hand side of this equality so we discussed that you know the how to get the solution of a homogeneous differential equation basically let me write my general solution u of t as e to the power lambda t and then we are going to substitute it back to the original equation so that I get after substitution plus a and that should be equal to 0 okay now e to the power lambda t term would never be 0 it won't give me any feasible solution so the only thing that can be 0 is what I have with the brackets here and that gives me the value of the lambda so there will be two roots of this equation this is the quadratic equation it would be plus minus under root minus k by m okay which I can write as under root k by n where I represent under root of minus 1 as the complex number i okay and this is nothing but let me just fix the view yeah so that I can write this as i omega n and we are going to discuss the significance of this omega n and this parameter so we are going to do that but let us first substitute our roots to the original equation which is u of t because it has now two roots I am going to write my solution as a linear combination of e to the power lambda 1 2 which represents the solution with respect to the first root and then e to the power lambda 2 which is corresponding to the second root okay so I will get here as and then b e to the power i omega n t if you remember from your complex numbers theory what did you have if you have e to the power i x you could write it as cos x plus i sin x remember and then e to the power i x minus i x can be written as cos x and minus sin x so if you make that substitution in this equation here and then again rearrange the term okay you will get something like a plus b cos omega n t plus let me just fix it here I will get it as cos omega n t plus i a minus b sin n t and again these two parameters can be represented as another constant the values of which need to be determined to obtain a specific solution this equation so I am going to represent as another constant omega n and then d sin omega n t all right so I have obtained the solution to this second order homogeneous equation linear homogeneous equation here now I have two unknown constant and that we are going to determine using the values of or the using the provided initial conditions okay so okay so let us substitute those values before that I need to differentiate it once to obtain the expression for u dot t so if I do that I will have as minus c omega n sorry this should be a sin omega n t here plus e omega n cos omega n t all right so let us substitute these values so u0 is equal to c and remember t equal to 0 cos omega n t is basically it would be 1 plus 0 because sin of omega n t at t equal to 0 would be 0 so I have obtained my value of c as u of 0 okay now u dot 0 would be equal to this term again would be equal to 0 plus I will have d omega n and then the value of cos omega t would be 1 okay so this gives me the value of t as u dot 0 okay if I substitute this to the equation that I had the expression that I had for ut I would get it as u of t is equal to u of 0 cos omega n t plus u dot of 0 sin omega n t all right so this is the solution of free vibration for the initial condition u of 0 and u dot of 0 and you know of course depending upon whatever the values of u0 or u dot 0 you have you can obtain the specific or like the numerical value of u of t okay so this means just let me write it this is as free undamped vibration okay so as you can see I have the expression for u of t and let us just try to plot this function okay and see how does it look like so I have a cos function and then I have a sin function okay so if you plot it if you plot these expression okay so what I have here is all right and then this is u of t and okay so I can write it as so if you plot it here it would look like something like this okay so what do I basically see here my resulted function is actually or the expression for ut is actually a harmonic function and also a periodic function which repeats itself okay it repeats after a specific time okay if you look at this graph here I know that whatever the initial displacement at time t equal to 0 was u of 0 okay and the slope initial slope of this ut is basically the velocity which I am going to write it as a u dot of 0 okay now in this case if you look at this or let me just write it like this take it from here so it has some kind of periodicity this function here okay and this periodicity is actually if you saw this function as you see the function here actually repeats itself after a or after 2 pi by omega n seconds okay and that you can you know prove by substituting or finding out the value of ut at time equal to t as well as t plus 2 pi by omega n t okay you can find that out from this and you can you can prove that the values are still the same okay now this quantity here 2 pi by omega n and then all the time after which it repeats itself is called the natural time period of the system okay so this is called natural time period of the system okay and remember that the value of omega n that we have obtained is under root k by n so now the value of t n would become using this relationship here 2 pi under root m by k okay so as I said t n is called the natural time period of the system okay and omega n is actually called the natural circular frequency of vibration okay so it is called natural circular frequency of vibration okay and as you can see from this relationship omega n is actually related to t n using this relationship here okay and the unit of omega n is actually radian per second okay and then there is another parameter which is called the natural cyclic frequency of vibration okay and we represent it using f and it is called natural cyclic frequency of vibration okay and the unit of this f is actually first let me just write down the relationship between f and omega n so they are related as you can see f is basically first let me in terms of the time period is 1 by t okay so this is the cyclic frequency of vibration okay and it is also related to omega n using this relationship here and the unit of f is actually cycles many places you will see it is written as cycles per second or in short cps but more commonly you will see that hertz as being used as the unit of the natural cyclic frequency of vibration okay now we are using the word natural quite a lot so you just have to keep in mind the significance of the word natural is basically that this is the natural means that it is without any action of external load and it is for an undamped system so these natural properties are so maybe I will just write it here natural properties are defined for undamped system okay without action of external load okay now it is very important to understand you know the physical significance of these parameters and what are the typical values that you would see for these parameters okay now time period as I said it is basically the time required to complete a single cycle of motion okay now if I have this graph here and if I had to represent it let us say for a system the spring mass system that we have discussed okay so let me say this is a this is b and I can take that for like you know for any section of this vibration cycle that I see here okay it would be c e at e okay so the motion is always considered about the equilibrium position okay and for many cases like an equilibrium position is also the initial position or the undefined position which is fine for example we considered when we considered the motion of a hanging the spring mass system hanging from in the vertical direction for that we said that let us consider the motion from this position so the initial position was equilibrium okay and then what we do either we impart an initial displacement or initial velocity okay or a combination of both okay so this starts from let us say a value of if I am measuring you from the equilibrium okay starts from a value of q equal to whatever the initial initial rate is provided so that would be let us say case a here okay then what happens as u is increasing it attains a or goes to a maximum say in this case somewhere around here okay and this is the maximum displacement of the system due to initial velocity and displacement okay and this is the position b that is shown here so this is position a this is position b okay so it will go to this maximum position then it again it will start coming back to the initial equilibrium position okay all right so this would be again c here okay and then it will go with the so when it goes to a maximum value of the displacement right here okay u would be maximum but the velocity would be zero okay and that you can see from this cycle here as it goes from a to b you can see the displacement is maximum however this curve is actually flat here which means that a slope of the this expression is zero the slope is actually the velocity of this spring mass system so the velocity is zero all right and then it starts coming back to its initial position okay and then it passes to its equilibrium position at which its displacement again becomes zero however it passes at the maximum velocity so at this point is what when is your velocity is maximum okay and that velocity carries this system in the opposite direction so the negative u direction as you can see here okay so I am going to represent that let me say here so this is the state d which corresponds to the negative maximum okay and then again after it attains this negative maximum it starts coming back to its uh equilibrium position at which it completes a cycle of motion and this uh you know this actually keeps on repeating okay so you this is the basic like you know the breakdown of a free vibration of an undamped system okay now let us come back to these three parameters that we talked about the time period the circular frequency and then the cyclic frequency okay and as I said that units would be second here it would be radian per second and here it would be hertz okay so uh now what do you think if I have a two if I have two systems a system a and a system b okay now system a if I am saying to you that a system a has very high frequency okay very high frequency okay of course uh you know this would be in comparison with system b here what are the things you can deduce from this information that has been provided to you okay if it has high if it has a system is a high frequency compared to uh system b there could be multiple possibilities one could be or like you know let us just list down those possibilities if the frequency is high remember that how is the frequency how is the time period connected to the frequencies is time period is either 2 pi by omega n or it is also 1 by f so it is inversely proportional to the frequency so that means the time period would be small small here okay large okay what other things you can deduce remember that my omega n is nothing but a by m so the frequency is higher that means it could be a stiff system okay compared to a flexible system and I mean this makes sense isn't it if you consider a flexible system can you physically imagine that a flexible system would take more time to come back to its or like in the finisher cycle of motion compared to a stiff system okay a stiff system if you give initial displacement it vibrates at a very high frequency okay high frequency means that there are a lot of or there are like you know higher number of uh cycles in a single second of motion which is basically consistent with this definition here 1 by f okay other possibility for the given scenario would be instead of saying stiff system or flexible system for a given same stiffness this could also be possible if the mass is small here okay so let us write down a small mass here it is large mass okay so these are the few of the possibilities that might result in high frequency system a system a with a high frequency compared to a system with b with low frequency okay so this you have to keep in mind if a system is stiff that means that it would have high frequency okay if a system has very large mass that means that it would have low frequency okay or I can also say that if a system a very large mass that means or flexible system then it would have large time period of oscillation compared to a system with a small mass and a stiff system all right okay once that is there uh let me come back to our expression for u of t again which we had obtained as u of 0 cos omega nt plus 2 dot 0 omega sin omega of nt and remember that we said that omega nt I can write this as 2 by by t so I can also write this expression as and then I can write this as similarly 2 by by t by tn okay now remember that we know from this graph okay what is u 0 what is u dot 0 uh we have also find out what is the time period of uh vibration or the oscillation okay there is one more thing that is remaining to find out remaining to be found out and that is the amplitude of the oscillation here okay let us represent this using u 0 okay so amplitude would be basically whatever the maximum values value of this expression that I have here okay so I need to find out maximum value of ut okay let us see how do we uh get that uh if you consider any function of type a cos let us say a cos theta plus b sin theta if you remember your trigonometric identities what I can do here let me uh multiply and in this case here I will multiply and divide by this under square root of a square plus d square okay and if you look at this carefully if I consider tan alpha equal to b by a then this expression is nothing but sin of alpha and this expression is nothing but cos of alpha okay but tan alpha as I said is b by a so I can write this further as under root a square plus b square and this would become cos theta into cos alpha plus sin theta into sin alpha and from your trigonometric identities I can write this as cos of theta minus alpha okay and that we can like you know substitute it back here so in this case remember my a is u of 0 b is u dot of 0 so I can write this whole expression as u of 0 cos of theta minus let us say I represent this instead of I will say this as phi okay now I know that maximum value of cos function is actually plus 1 so that the maximum value of ut would be let me write it as u naught with this okay so the free vibration with initial displacement and velocity happens around this static flip game position with an amplitude which is represented by this here okay all right once that is clear okay let us see how do we find out the important dynamic properties of the system okay till now we were deriving our equation of motion as mu double dot plus cu dot plus ku equal to phi of t we said that for a free vibration this equal to 0 for an undamped free vibration this equal to 0 okay so a simple problem on this would be a system an undamped system would be given to you okay and you could be asked to find out what is the value of omega n which you have to find as k by r m remember that there are multiple ways to obtain the equation of motion in terms of different degrees of freedom as well okay however whatever you do the omega n should be same because remember omega n depends on the stiffness and the mass of the system it does not depend on the applied load so it is a property of a system okay it does not depend on the applied load so that you have to keep in mind okay so once I write this expression omega n equal to under root k by n you can obtain the equation of motion differently with different coefficients okay point is what I am trying to make here is whatever the way you obtain your equation of motion your omega n should be in the simplest form coefficient of the stiffness term or stiffness force okay so basically here okay divided by m which would be the again coefficient of instead of saying the stiffness force let me just write it as coefficient of the displacement okay the second term I can write it as coefficients of the acceleration all right so using this I should be able to obtain my omega n which is of again as I said it is in radian per second okay and then I can find out the time period of the system as well as the frequency of the system okay all right I hope up to this point it is clear to you okay now what we are going to do we are going to do an example okay and this is not a problem for a book what we are going to do we are going to take typical property of the values of a system of a building let us say with a column and like you know beam and then see what is the value of the time period that we get okay so let us say a typical single story building is what do you think is the typical size of a room would be okay it might be let us say 10 feet by 10 feet of course if you live in Mumbai then it might even be smaller isn't it okay anyway so let us say I have this and I want to find out the time period of the lateral motion okay there was a problem remember in which we had considered torsional motion but right now we want to consider only the lateral time period of the system okay so let us say you know I mean there are four columns a typical column could be 300 mm by 300 mm and there are four of those remember e of concrete let us say it is 25 mpa concrete okay so let us say it is 25 mpa concrete column remember that e is nothing but 5000 times under root fck okay so I would get as e as 2500 okay 2500 mpa okay and if I consider these not to be actually let me just again write it or let us just say this is the fixed fixed connection although in reality it is not like like you know always fixed fixed like you know many times it would be pain because to like you know provide fixed it we need to do additional detailing and like you know provide rigid support to the ground okay but anyway just for the sake of this calculation let us assume it is a fixed fixed connection okay so remember that what was our stiffness in that case was 12 ei by l cube okay and a typical story height you can assume as let us say 3.5 meter okay so if I substitute it here I will get as 12 times e which is 2500 mpa okay and this I can write in 1 mpa remember 1 mpa is nothing but 10 to the power 6 Newton per meter square and what would be i of a section okay so if I have a section like this bd remember if it is bending about this axis then it would be i would be bd cube by 12 and in this case both are same the square cross sections so I can it would be just 0.3 to the power 4 divided by 12 that is my ei and the length is 3.5 into the power cube okay and this need to be found out so you can calculate this value okay let us see what do we get when we calculate that okay so okay so I get it as 47230 p okay and that would be let us say Newton per meter now in terms of mass what I could do I could lump all the masses here okay so half of the mass of all this and remember this is for one column sorry so what I need to do is use four times which I let us say I will do in the final calculation it is first talk about the mass mass you can lump it at the roof level by assuming that half of the mass of this these columns are lumped to the roof slab here okay and then the dead weight of the roof slab you can add it to that okay and then you can also add the live load okay and all those would come contribute to the total mass of this system okay so for the mass of the system let us say I have four column and I would assume that half of this is actually lumped okay now remember that cross section area is 0.3 by 0.3 and then I would have to multiply this with 2400 which I am assuming as the density of the concrete okay this is for the column for the slab let me assume like you know typical slab of 250 mm okay so in that case the total would be remember that the slab dimensions I can assume this has to be 4 meter by 4 meter okay so it would be 0.25 thickness of slab times 4 times 4 and then again 2400 so this is basically the dead weight okay but in reality there are other type of things as well for example floor finishing is there there might be like you know other things that are installed on top of it because I do not have information regarding that I am going to neglect that however what I am going to do I am going to assume a live load to this slab here okay which I would assume as a live load acting as 3 Newton per meter square okay which is very typical so I will write it as 3 Newton per meter square times the area which I have here is okay and remember that I need to convert this to into mass unit system here okay so this is Newton so to convert it to kg I will multiply this with 9.8 okay so let us see how much I get 4 so I am getting as kgs okay so let us say if I use this what do I get as time period b this is the mass and then I have four of these four of this column here so I get it approximately as 0.5 second and as you like you know do more and more problems and calculate the time period you would see that 0.5 second is very typical of like you know low to medium rise building as the height of the building increases the time period would actually increase but using these typical values we have obtained the time period to be approximately 0.5 second okay so depending upon what kind of structure it is I will give you some typical values of the time period of different type of structure okay so you know buildings depending upon whether it is a low and like you know low rise building or high rise building it could be between let us say 0.4 to 1.5 second actually for high rise building if it's a very stiff structure like nuclear power plant or something like that okay then it's a very stiff structure so the time period would be very small it is around 0.2 seconds okay you have typical values between 0.2 to 0.3 second or you could have very flexible structure like a suspension bridge okay and which could have like you know depending upon which direction you are considering time period even like you know seven to eight second in one direction or like you know three to four seconds so depending upon the direction you could have like you know different time periods which are like of typical values like you know varying around six seven second or three four seconds so you know it's a good practice to keep the value these values in mind to reflect like you know what are the typical values of different type of systems for their time period and frequencies just to get a feel of the these numbers and these parameters all right so with this I would like to conclude the lecture today thank you


Welcome folks, we at the Dow Industrial has finished up 39, Nasdaq up 110, S&Ps up 12, gold contract down $17.20 trading at $18.48 an ounce, we at Silverloft 23 cents, $21.63 an ounce, Lightsweep crew down 40 cents, $78.65 a barrel, notes and bonds. Ten year note, down 7 ticks, trading $1,1203, the 30 year up down 26 at $126.11 and $King Dollar. $King Dollar up 615 ticks, trading $103.848, Euro 106, Yen 133, 134.12, British Pound 120 to 1 US Dollar. We get open, we take a look at the spy folks, you get an inside day out here, you get light volume inside the spy, we did 55 million shares, the high of yesterday was a bottom line, let's say 415, 05, today your high is 414, that being said, my take is that this is going to somehow, this is going to go for the swing point which is established out there last week. That swing is at that 418.21, inside the NDX 100, it's the same type of setup, inside the NDX it's more clear, meaning that because it's such a high volume swing. We had volume yesterday, volume came in yesterday at 64 million, did 41 today, did a contraction but it's going after the 83 million, at 313.68 and right now you're at 309.10. Notes and bonds, this is going to be the problem here, we're going to keep shaking back and forth, back and forth, but on the longer play you're going downtown. This note and bond market, this tenure note, you know yesterday had 2.7 million contracts as it broke the swing, bottom line, you're down 8 ticks today, the bottom, you get two different little swings, well the bottom is 112.05, 112.02, you know it's 111.28 actually, it was a spike, but this thing is on its way down to the 110 area, the low in the tenure folks is 109.06, so when we were at 109.06 I think it was 4.4, let me see this, so the high, I got to go to six months now I think, there it is, 4.24, 4.24 and right now we are at 3.8, so rates, higher prices, lower, have a great night, safe night, come back and visit Tommy tomorrow morning folks, look at him folks.


Inclined Press Lie back on the incline bench and take a shoulder-width grip on the barbell. Extend your arms fully, thereby lifting the barbell from its supports. Pause briefly in this fully extended position to ensure proper balance. Once balance has been obtained, slowly and deliberately lower the barbell to your upper chest. Pause briefly in this position and then press it back to the starting position. Reps 8 to 12. Note can be done with barbell or dumbbells. Hey thanks for watching my Bruce Lee training and workout video. There's a lot of videos in this series so make sure you check those out too. If this is your first time here make sure you click the subscribe button and get the latest workout martial arts fitness and self-defense and fighting tips. Alright so we see you in the next video.