So We have always said public keys are public, but we now have this issue Well, how do we really distribute them such that we know we've got the right one? It's not someone pretending to be a user Well different approaches public announcement yell it out So what I do I generate my public key and while we're in the class I read out the values Or maybe a signature of the values You download my public key. I read out the values and you confirm because you see it's me You trust it's me and see that that is my public key. Now, you know that you have my public key So some form of announcement That works on a small scale when you're physically close to people But it doesn't work on a large scale and across a large area Have some form of directory like a website where everyone uploads their public key and When you want to get someone it's public key you go to that website and download it But we have that problem. How do we trust that the attacker hasn't modified the values on the website and Then we'll see two more secure ways a public key authority and public key certificates Public announcements just send the public key across the network But we saw with the simple key distribution scheme that doesn't work because of a man in the middle attack if User a sends its public key to be There's no way for B to know for sure that it's got a public key. It could have been an attacker in the middle So That's the problem with that approach Now the announcement may be done via a network It may be via old means of publishing it on an email or a website or a newspaper Maybe a little bit more automatic use some special directory Where you publish the public keys in the directory in advance and When you want to let's say B wants to learn a's public key It contacts the directory and downloads a's public key But same problem we have how do we how does B know that it's got a's public key? We need some form of authentication So we'll arrive at using an authority What we'll do is that each user has their own key pair They're going to publish their public keys in the directory and The directory will call here the authority the public key authority and When a user wants to communicate with someone else, let's say a wants to talk to be a Will contact the directory or the authority here and say give me the public key of B a will contact be and B will also need the public key of a so it will contact the authority saying give me the public key of a You will get the public key of a and then they'll do some final authentication steps to check that they're communicating with the right entity This can happen automatically. So this is a protocol that can be run between the different computers involved So whenever a wants to talk to be it we go through these seven steps We'll go through them in some depth look at the messages and look at the Some of the design issues here some of the advantages and disadvantages of doing this remember the aim is that a knows B's public key and Also B knows a's public key if we know the public keys and we're sure they are the correct public keys Then we can use them to exchange secrets or whatever else we want to do later The aim is to exchange public keys Let's go through the steps and and keep track of what What we know and what we learn along the way First we'll list what is known by the entities before any of the messages are exchanged. So A wants to talk to be we're going to exchange these seven messages But before that we assume that a knows some information B knows some information and also the authority What do they know at the start? Everyone knows their own key pair. That's the first thing. So we'll list that a knows The public key of a and the private key of a B knows its own key pair and the authority also has its own key pair So we assume they know their own key pair But also before any of the exchange takes place We'll assume that the users have all published their public key to the authority That is the authority also knows Pua and Pub and they are the correct public keys An example being I'm the authority and Every student comes to my office. They show me their ID I confirm that stem and they show me or Electronically give me their their public key and as the authority I store that in some database So the authority knows the public key of a and the public key of B Our aim is for a to know the public key of B and B to know the public key of a what else When a went to the authority and gave The authority its public key the authority gave a The public here of the authority. So at the start a also knows P you of the authority and so does be I just list that here In other words every user must exchange their public key with the authority before this works If we have a million users, they must all exchange with the authority Now this scales okay because as you increase the number of users that the number of initial exchanges increases linearly So this centralized scheme like the KDC We need one manual exchange per user But that must take place securely in advance So now what we want to do is a communicate with any other user in this case B And we want to do that automatically because let's say we have a hundred users if there are a hundred users there were 100 manual exchange with the authority a exchange with authority B with the authority and the hundred users all did it centrally to the authority 100 manual exchanges, but now we want to allow any user to communicate with any other user They all need to do an exchange. How many possible exchanges are there? We are hundred users. How many pairs of users are there? If you remember from two weeks ago Anyone remember the equation if you have 100 users, how many pairs are there between them? 4,450 100 times 99 divided by 2 So about almost 5,000 so The reason we can use manual exchange with the authority in this case is because we only have 100 to do manually, but if we wanted to do manual exchange between the users We'd have almost 5,000 exchanges many more and that becomes too inconvenient so that's a It's okay to manual exchange with authority, but not between users Hence we use this protocol of seven steps to exchange between users First step a sends a message to the authority some form of request It doesn't say in this picture what the request is, but maybe it contains the identity of a and b So we just say a request think the request is saying I'm requesting the public key of B So the request actually may contain at least the ID of a and the ID of B What's T1 a timestamp? So we send a request to the authority. I'm user a saying I want to learn the public key of B and So that request should contain my identity. I am user a the identity of that Entity I want to communicate with B and a timestamp T1 Do we do not hear saying this request came at this particular time? Why do we have a timestamp? What's the general type of attack we try to defeat with timestamps? What's the name of the attack? replay attacks Hard to perform if there's a timestamp we send at this message now We include the current time very accurate if someone resends this message Five minutes later the receiver can easily detect. This has been delayed by five minutes or it's been replayed Let's not trust this recent message. Okay, so it provides some Some information to the authority that this is a current message and Also, we'll see it it comes back in the response So the a knows that the response message to Corresponds to a response to the initial request so it's like some sequence counter or some value that The receiver can check that it's not an old message or a replay of a message It's a request for the public key of B. The authority has the public key of B So it sends back the public key of B But we can't send it unauthenticated If we send a public key unauthenticated someone could intercept it and modify it So we see we authenticate that message The public here B Including the original request ID a ID B and the same timestamp and We encrypt that with the private key of the authority Encrypting with a private key is signing We sign the message or the authority signs this message Confirming this came from the authority When user a receives message to what do they do? Decrypt and the name of that process of decrypting we call starts with a V We verify so we say that the authority signs The public key of B How did they sign it they encrypted with the private key of the authority when a receives a signed message they verify to verify you decrypt with the public key of the sender and We said that a already has the public key of the authority so they can verify that this is indeed the Message that came from the authority When a receives message to they verify the message using a public key of the authority They find it passes the verification because it was encrypted with the private key of the authority It successfully decrypts with the public key of the authority therefore verification passes So they know the contents included are valid They've learned PUB so that's the first discovery of a message and as a result of that after message to We know PUB a knows PUB remember our aim a to learn PUB B to learn PUA Before we look at the next steps What if an attacker intercepted message to what could they do? Right if an attacker intercepts message to they can learn the public key of B Remember message to is encrypted with the private key of the authority Everyone knows the public key of the authority. It's public So this does not provide confidentiality Anyone can see the public key of B So the attacker can learn PUB they can learn the request and T1 So what they learn the public key of B we know that that's okay because it's the public key Can they try to modify anything? they intercept message to and They're trying to trick user a and to get a different public key They change PUB to PUI the public key of the imposter Will it work? Yes, it will work They intercept they can learn PUB they can change PUB to something else But when they send that modified message onto a what is a going to do a is going to verify Using the public key of the authority any message we receive from the authority the second one We verify with the public key of the authority And it will only pass verification if it was encrypted with the private key of the authority Therefore if an imposter tries to modify this message to along the way They can't encrypt it with the private key of the authority because they don't have it They need to encrypt with some other private key But when we try to verify with the public key of the authority it would fail the verification so Encrypting with the private key of the authority Means that if someone tries to modify it a will detect that modification and that's our authentication That's how a knows It's got the public key of B It hasn't been modified Any questions about the first two steps is just to get PUB to a I asked for it Authority sends it to me, but importantly it sends it to me signed by the authority We want to exchange public keys, so we keep going A knows the public key of B now a contacts B for the first time sending a message to be saying Let's communicate. Let's talk. It uses the public here B to encrypt Its own identity and a nonce value again a random value or some number that will only be used once and It's hard to predict by an attacker It's encrypted with a public key of B Therefore no one else can decrypt that message except B Only B can decrypt this message So if an attacker intercepts message three they cannot learn and one B receives this Realizes that a wants to talk to it Step four and five are similar to step one and two B now requests the public key of a from the authority The authority sends back a response containing the public key of a Signed by the authority B confirms and learns pu a it verifies message five and Learns pu Hey, so just to make that clear that the steps that are important here the public key Authority signs this message and when a receives it verifies and Similar with message five it's signed by the authority and when B receives it verifies The way that it verifies is using the public key of the authority which we assumed was known at the start after message five We've achieved our aim a knows the public key of B B knows the public key of a But we still have message six and seven and they are Used to to confirm that there are no replay attacks or no modifications along the way Like in the previous protocol where we want to be sure that we're talking with the right entity message three contained N1 The only person who knows N1 is a Let's say some random value Message six coming from B also must contain N1 If it contains the correct N1, then it confirms that B Was able to decrypt message three which confirms that message six comes from B If you can decrypt message three you must be B B also includes N2 in message six and A sends back that same N2 in message seven so when B receives message seven it knows it's talking to a So really three six and seven AMB checking are we talking with the right entity? We'll just jump back to one of the previous systems one two and three The purpose of those three messages a and B to confirm they're talking with the right entity Exactly same purpose as three six and seven here If you look closely they're using almost the same technique they send the nonce values Encrypted with the other entity's public key Questions on how do we use a public key authority to exchange public keys? Correct That all of information that that you send them all the public key that they're listed it's trustworthy like How do we kind of it you can pretty much do the same thing? Correct all of this assumes that the authority is trustworthy That is So at this so we're assuming that somehow before we did all this we have confirmed It's the right authority. This is this manual exchange. So Right it could be that in the example that I said you are the users I am the authority you trust me as a lecturer at the start of the semester you come to my office We provide some ID we do a manual exchange and I learn your public key. You learn mine as the authority then after that all semester we can use this protocol and Each student can talk to each other student using this protocol by automatically exchanging public keys But yes, we don't overcome this problem of we must trust someone Because We need to get started somewhere if we want to Exchange a shared secret key Across the network that it must be encrypted if we are going to encrypt it. We must have a key to encrypt it Well, we can use public keys, but our problem always with public keys. We must know it's the right public key And the only way to cryptographically do that is to have it signed by someone but if we sign a message we must have a public key to Verify that message so there must be some initial trust. There's no way around that here In this case the initial trust is a trusts the authority When I say trust here, I mean a has the public key of the authority and it knows for sure It's the correct one and that issue is a practical issue. That is how do we trust other entities? Maybe you trust a government or you trust your employer they they set up the system in advance such that we Have that initial trust built into the software or into the system We'll see that a little bit more with web security and digital certificates So let's summarize on the scheme here the aim a and b get public keys The assumptions every user trusts the authority and they've exchanged public keys with the authority That must be done manually in advance the automatic steps request the public key of B Receive the signed public key of B from the authority in message to a Verifies the signature of message to using the public key of the authority Message 3 is telling B that a wants to talk to it. So B does the same as message 1 and 2 it Requests a's public key from the authority the authority sends a's public key back, but signed B verifies message 5 Okay, it learns the public key of a 3 6 and 7 combined A and B checking are we talking with the right entity with this exchange? There's no way for an attacker in the middle to modify a message and Try and pretend to be one of the others for an attacker to pretend to be B from a's perspective or vice versa because These messages are encrypted with public keys We have confidentially confidentiality of those messages and because the contents are random numbers or nonce values The attacker cannot guess what they are in advance What's the problem with this we trust the authority is one problem We'll see we can't get around that if we want to use a centralized approach What's another problem? Maybe not a security problem performance wise performance a problem There are seven seven messages to be sent across the network to do this every time a pair of users want to communicate they Exchange these seven messages. So there is some communications overhead usually not large Let's say we need to do this every five minutes a wants to communicate with someone else they go through these Seven steps just send some packets across the network software does it for us But maybe performance with respect to the authority can be an issue the authorities like a server A and B are computers in the network every time any Computer wants to talk to any other computer We see the authority must receive a request sign a public key and send it back twice in fact So there's some load on this authority. It must sign two messages for every time a pair of entities want to communicate if we have thousands of users wanted to communicate There are many requests coming to the authority and the authority has to sign those requests and send them back So there's some performance bottleneck at the authority if this is slow If it can't respond quickly for a response then the communications between the users will be delayed So yes, some performance issue with the authority. It's we depend upon that and also some trust issue with the authority We can't overcome the trust issue We must trust someone to get started We can overcome the performance issue So we looked at using the authority to distribute public keys The authority can be the performance bottleneck everything goes through that entity that server if it's slow that whole system is slow You can speed things up by caching some of the messages the way to overcome that Every exchange goes to your authority is to use a concept called public key certificates


You can do both. You can do both the simple infrastructure and the simple continuous So the initial steps will be the same The initial steps will be the same. So there's not a problem. Now. I'm demonstrating the next one simple running sutures One group is still missing Chris Zara cheese them Initial step is the same the first bite is the same get a good grip full thickness opposite side full thickness Pull it out with a curbing motion as usual First one we will put the knot as usual because we have to fix it So see I'm doing a little bit like this. There is a reason for that that sort of you know embeds the knot next I'm tying it off Okay, now what I'll do is now follow me very closely Unlike the previous time What did we do we cut this off isn't it how we are going to cut it? I'm just going to leave this behind the long loop still remains in my hand I'm going to catch hold of the needle back And this is going to be my stay. I'm going to keep it out of the way again catch hold of Come on and get a good grip opposite side Good bite pull it out with a curving motion first one next again Good grip Approximately half a centimeter away another bite Come to the opposite side Another bite Pull it out. You see how the switches are coming now. They're coming parallel and slightly oblique We'll take a few more throws and Then I'm going to show you the last step Continue Get a good grip approximately half a centimeter away Full thickness Full thickness This is the simple running or the simple continuous both mean the same Continue half a centimeter When you're taking the bite like I said in a normal patient There are no dots What do you do is you just give a gentle push with your needle and you see the bulge Then you know exactly where your needle is coming out. That's how you align yourself So give me can you see a small bulge and I know that's where my needle is coming So I have decided that this where I want my needle to come out in an actual situation. Also, you will see that If the tip is very small, don't try to grab hold of the tip Some of you will do it and you'll break the tip and the tip will go to the wood And the next two hours will be searching for that small tip that has happened So give a little extra push so that the tip comes out nicely These are small finer points and then get a good grip and give it to pull it out of the curving motion Many people try to put it out straight. Then also the tip breaks once in a while give it a little Like this so that the Ends are perfectly united. These are all the techniques to make sure that you get a good scar It automatically becomes a leak because you're bringing a running switcher, isn't it? Next I'll take two more and then I'm going to stop it by it Because the last part is important. You have to see how to finish it This is going to be my second last and then I'm going to stop it. This is going to be my last So this is how you should get Now watch the end We have only one then So the question is how will we loop it and how will we stop it? That is the crucial one So let's say my suture. I've finished my suturing and I'm going to this is my last one So how do I finish it? So I'm taking my last stitch now full as usual As usual Okay, now what you do? Do not complete it keep a loop Do not pull it full keep a loop and this is going to be my not Usual two loops catch hold of the apex Next again same procedure catch hold of the apex Catch hold of the apex same way and there you go and we finish it off. So please do the Simple


We are now going into our third year of our world facing a global pandemic. While there was a change in what we now define as normal, what does not change are the core characteristics that are the heart of U.S. Special Operations Command Korea. The past year included a change of command as SOC Corp. Major General Michael E. Martin as the commanding general and command sergeant major Joanne Nauman as the command senior enlisted leader. We prioritized readiness and strengthening relationships with our Republic of Korea SOF teammates. This included U.S. training with airmen, sailors, soldiers and Marines that came from duty stations in Japan, Washington State and California. We also focused on building a resilient battle staff, whether that was understanding operations in a more dynamic fashion or looking at our diverse command and seeing how we can become more inclusive. We cannot forget the families both on and off Peninsula that took on the adversity and challenges of military life while managing the safety guidelines that accompanied COVID-19. Their support makes our mission possible. Now, as we go into the year of the tiger, it is a perfect symbol of the special operations dynamic that we share with our ROC teammates. Characteristics of bravery, courage and steadfast will. These are shared amongst our communities, regardless of language. We're ready to drive into this new year and new opportunities. Concilio Preveo, we go together.


When I was young, I was really obsessed with the stories about Qigong masters. Where you'd hear about the old sage in the Himalayas or on the Chinese sacred mountain, and there was this Taoist mystic who could somehow perform miracles by doing all their little Qigong breath movements every day. Now studying Qigong has been a piece of me studying Chinese medicine, and I've always been curious about what it could really do, and why I should honestly do that over exercise or do that over something else that I already really enjoy doing that I know is going to help me live a long and healthy life. Well in this video, I want to share what I learned doing Qigong on and off for truly about a year, and even though I'm sharing that it's about 30 days here, I want to share some of the experiences that I had. Hey, Alex Hine, author of the book Master of the Day. Now I've included the first link in the description is a free download for a PDF, like an infographic, which is five daily rituals that can help you add 10 years to your life with traditional or classical Chinese medicine. So if you want, you can click the first link in the description to download that, and then you're going to get that sent right to your inbox. So the first thing that I noticed after doing Qigong is this idea that I call somatic sensing. So one thing I've noticed that's different between regarding exercise and Qigong is that I've been going to the gym for 10, 15 years and I can do an hour long weight workout and still have cold hands a little bit. Now the difference, when I'm doing Qigong, within five minutes my hands are warm and even hot. Now I think just subjectively in terms of think about what that means for circulation and think about what that means in terms of, in Chinese medicine, there's a saying that the Qi guides the blood or the Qi precedes the blood. So if blood is coming then Qi is moving. So what's crazy is that how could I possibly exercise for an hour and yet for whatever reason I'm not getting circulation to some of my extremities. In Chinese medicine, one of the reasons for doing Qigong is that it's supposed to be able to, number one, you begin to have a better radar for what's going on in your body. It helps develop this subjective sense of where are things not working? Where is the flow interrupted? Now that could be as obvious as I'm bloated or I feel a weird stuffy sensation in my chest or my hip hurts. But beyond that, doing Qigong is supposed to allow you to feel certain qualities of your patient better or the person you're treating. So for example, it's allowed you to get a better accurate diagnosis, a more accurate diagnosis to impulse. It's supposed to allow you to feel things you ordinarily can't feel in regard to just palpating a person like massaging. Just palpating a person and seeing what's going on with the channels in the body. So for me, this subjective feeling of warmth was very interesting. Now the second thing I noticed doing Qigong daily was movement. So when I say movement, one thing that Qigong is supposed to do that we talked about is make you more aware of what's going on in your body. So if you're someone that's not that sensitive, it can help you actually to become more sensitive. Now one thing that would start happening doing Qigong in the morning was that I would burp a lot. I would fart a lot. I would feel a lot of pressure in my intestines. And I would feel all of these sensations. But overall burping, farting and then later having a strong appetite in the morning, which I almost never do, was really very telling to me that it was moving something. So in theory Qigong is first supposed to help you be aware of those blockages. And then second, it will eventually with time clear those blockages. So to me it was very fascinating that number one, it was making me aware of what I was feeling in my body, often indigested, often bloated, often gassy, and then I would burp or I would have gas in the morning. But then ultimately I would have a good appetite. And that was very, very interesting to me because that was part of what the promise of Qigong was supposed to do, make you aware and then eventually move and fix some of those blockages that were actually going on inside of the body. Now that's pretty cool because that's part of the self-healing mechanism of the body and what Qigong is really designed to do, which is in the absence of movement, of exercise, of changing your diet, of taking a drug or an herb or whatever intervention it is, Qigong by itself can help regulate the person's body to kickstart that self-healing mechanism. Now the third sensation that I felt was being calm and warm. So one of the first things that I asked a Qigong teacher was what's the difference between Qigong and doing exercise? Because honestly I like working out much more than I like doing Qigong and I'm very disciplined about that. So why do this for my longevity or feeling well as opposed to just going to the gym? And what she told me was that there's three things. Qigong entails breath work, so changes in your natural breathing rhythm, visualization and physical movement and doing that often even with other things on top of that is the difference between Qigong and just going to the gym. So while I was doing Qigong, I was doing certain kinds of breath work so that typically meant instead of my normal breathing, maybe inhale is every two seconds, exhale is even shorter, my inhale and exhale were up to eight seconds long each. So that's like a double triple or quadruple the length and duration of my breathing, lengthening the breathing. So you can think what all that added oxygenation does to your tissues, to your brain function, to your energy, to your digestion, to everything. Now that is the calm part and the warm part was that increase, obviously the increase of oxygen made a lot more circulation for me. So I would feel warm, my whole body felt warm, my extremities warm and calm. So it was a big difference, especially if I did Qigong after an entire nine to five work day, I noticed the difference after versus before.  And then within 10 minutes of Qigong, my breath was very long and relaxed and my hands were warm. So to me, this warm and calm phenomenon was very, very interesting and I understand how that would be very strongly correlated with longevity and a healthy life. So I hope that helps. Those are just my personal revelations doing Qigong for a while, trying to understand what it's about and why to do it. And this is one of those things that always has puzzled me and a little bit frustrated me because I couldn't understand why I should just do this versus just going to the gym, which I already love and I already do and I have done for over a decade. But hopefully that provides some insight for you as to whether or not you want to investigate it, find a teacher or whatever. But I hope that helps. And of course, you can check out the first link in the description, which talks more about practices like Qigong. It's a free infographic that is five daily rituals you can use to potentially add 10 years to your life with traditional Chinese medicine. You can click that link, first link in the description. And otherwise, check out my last related videos right there and right there.


So also I want to say hi to everyone that is going to see this in the future with recording this so that it can be shared with others that whatever reason could not join us today, which actually is, as I said, it's very common being such a global school. Let me share my screen now. So, perhaps it's very important to identify yourself as a school that is really ready for change. Our school is not fixed. We don't have, let's say, the wish of remaining in mobile or kind of fix on our own ideas but rather we are embracing change and innovation, and we want to anticipate what the future of architecture is. That's why our logo expresses this permanent transformation and we don't have a logo we have sort of an evolving way of identifying ourselves. The AD is actually the most experimental part of the school. It's the program the program that that allows itself to go deep into research and also to understand how design is an opportunity to reinvent the world. So we're here in a very whole every hall is a historical building, but actually for it for us it feels very much the opposite very lively, then full of ideas of people, but also a container of the knowledge that architecture in this whole diversity. It's produced and accumulated in the in the last centuries. And that's why we are literally standing on the Avery library, which is the library of reference in the world for architecture so so so for you this is this means that that you're automatically connected to this knowledge and that everything that will happen during the time that you're here and beyond in the future as an alumni of the of the school is very much constituted by the and connected by all this diversity of knowledge in architecture and knowledge and architecture that the Avery library captures our pedagogies are designed to provide you an ecosystem where you can explore how architecture, it's part of the most important tensions that are reshaping the world societies climate, equity, data and technology. These are basically the pillars of our, of our pedagogy, and we basically do it not as a form of instruction but rather providing you a very complex ecosystem of possibilities where you can choose and navigate how you want to track your path. And that's something that of course it's requires a lot of attention on our end, but that translates into basically making sure that everything that is happening in the world. Climate crisis environmental crisis social tensions new ideas of how we work together, the way bodies are extended in technologies new ways of understanding nature as something that these architectural lies, even the notion of human are something that is designed and constructed in the communities that that are produced to this process, social media technology data, AI, also new forms of understanding gender ecology not as a problem but rather like the paradigm in which we operate but also the risk societies are facing now and the way architecture minimize reduce adapts to it. It's basically what what the context for architecture is. But we do these two structure and design, and we have eight tracks eight lines of work eight tensions that are accumulating our efforts and that allowed you actually to find people that can help you getting deep into many of the sensitivities and questions that you already bring to the school. So we're not expecting you to come as an empty, let's say person that we will start but actually we're very interested on your personal stories what is important for you, your cultures, your sensitivities, and we, we want to make sure that whatever is important for you, you can find in our school lines of work that can help you grow and develop your already existing concerns and abilities and sensitivities and and the first of this track, it's the environmental engagement, which of course it's not unique, there's many, many ways of understanding how architecture helps producing environmental engagement and we actually want to map all of them and to see how different they are to design to research to information to lecture seminars. The second is how to turn technologies accountable and that's of course a crucial point and and Dibor at the time that of course we're seeing very rapidly machine intelligence over passing the capacity of human intelligence. And so this question of how we turn accountable our technologies how we make social media space for democracy how we understand the way technological systems can empower individuals and communities and ecosystems. There's also a line of work that how could we not be paying attention to the third one is the articulation of the societal. This is crucial, we believe that one of the key capacities of architecture, it's to operate socially and by this I don't mean to just be, let's say supported of these franchise, but also how the actual societal alliances are produced at all different levels in all different situations so how architecture works as a mediator as a facilitator as an assemblage a society itself, are part of long traditions that we can we can build on. And that is of course a crucial part of also what architecture is now in the tensions of evolution how it is going to be reinvented in the future we want you to have the tools to do that and to immediately be at the highest level in that discussion. There's a totally different way to approach materiality now in the past materials were selected in architecture mostly through their aesthetics or capacities, but now the discussion is much more complex, it's about this long span like life span. The precedents that what are the labors that are included in its production mobilization installation, but also what is the future of materiality, once placed in a building, how materiality connects to bodies and environments at the time that is already mobilized as part of the production. So, so all these very complex questions require also research laboratories, new theories concentrations but also design forms of design, and that's what we do here we bring all these so that you have the capacity to very rapidly operate on material cyclabilities. The fifth line and track of work, it's inter species relationships in the past architecture has been promoting anthropocentricium. But of course that came to an end, we know now that our future is intrinsically linked to the future of many other species, and actually biodiversity became a way for humans to work under the possibility of their existence, we actually know now that there's no autonomy of the human body, the human body, it's 70% composed by other species so we basically are ecosystems, and the way we negotiate our relationship with other species is actually a big focus of architecture of experimental and avant-garde architecture now that we definitely have a voice on and we want also you to be empowered by by by being able to become an expert on how to do that. The sixth track and line of work and tension for evolution of architecture societies ecosystems is the connection and the articulation of the online with the offline. How could we not address this question. The part of our life is now delegated to automatized systems and to I a systems and to digital systems, and we want to make sure that we are not working with a notion of architecture of the 19th century, but that we immediately install everyone's practices and research and knowledge. What happened right now, we will see that we have a number of faculty that are working on these issues and that you and you, those of you that are interested on this, you will find the opportunity to, to go deep into this. The seventh track and line of work is an acting identity, and that has to do with the decolonization of our practices. So, discussions about racialization and racism across the world but also non binary gender identities gender tensions feminism, weirdness and radical forms of echo and queer ecology. And of course a very, very intensive field of work now and debate, but also very intensive field for design. And, and we want to make sure that that everyone in the, in the, in the program. It's familiar with how to and cast the tools, and it's a power to navigate these discussions and these possibilities for architecture. You know, if you might at the end, moving all the tracks. And the last one is geopolitics in the making architecture it's operating across scales. It's no longer something that operates only at the scale of the building, but the buildings by looking at building buildings we also expand in the tiny scale of bacteria and the large scales of geopolitics. And that's something that we, we've seen through infrastructures to the expansion of cities to the architectural devices that are designed to, to address a specific geopolitical questions. And, and of course we want to make sure that this is again something that we bring to this to the program so that you many of you have the possibility of exploring become experts on this. I must say that this is basically the way we do this is that everyone in the first semester becomes very familiar with all these tools, these ways of doing mobilizing design these ways of research and this very diverse ways of addressing individual practices, so that everyone in the first semester become actually experts on on all these lines of work. But then you start deciding how you want to decide your trajectory in the program. The professional definition that or academic definition that you want to have when you graduate and you will start choosing how to mix how to take pieces of these tracks and how to actually be shaping your own expertise. Ultimately, what we're basically with these programs stands for is to understand but the, that when we see buildings like this when we see an architectural setting like this in New York.  And this is crucial. We want to make sure that we don't approach architecture in a superficial way, but rather than we mobilize the entire power of design that we really are able and prepare an expert on mobilizing the power of design to transform the future, and to transform it in a way that it helped us address the fundamental questions that are shaping the times we leave and that will define what the future of humanity will be in the next decades. We do it through a very simple structure, simple so that you can use it easily, and that you can basically make it yours. The first semester is the semester that we actually make sure it's very intense. So even before you come here you will get already some text that we want you to read and to participate in some of the first week discussions and experiments. But it's also very fun, I must say, and everyone remembers this first semester as the moment of opening and ideas and meeting your peers and discuss with them, lively, but also imagination fun. But basically this is the moment that the class comes together. We start with a multicultural welcoming where everyone is really celebrated and we want to make sure that we all know what is unique about each of you. We actually even celebrate the way each one express themselves and what are your languages your idioms your references what is important either very elevated or very simple what is that that each of us like and it's an opportunity to know each other from what makes us different. We highly believe in the uniqueness of everyone and we want to preserve that. So we have advanced architectural design studio transhumanities and arguments and these are courses that are taken by transhumanities arguments by the entire class so it becomes an opportunity to know each other. And then we have two semesters, the fall semester and the spring semester that are also very intense, each of them very different, where you have the capacity to choose. I'm on a large pool of courses. Let's explain a little bit better than the first semester. The first semester, the, the most intense course is the advanced architectural design studios, you will have to choose I'm on a pool of 10 studios, very different. These lines of work that I was presenting before, they are represented in the studio so you will see that for instance some of you will want to work with an area Calvillo on the development of interspecies relationships to design others others will work with Marco Ferrari on projects that are at the scale of architecture at the scale of buildings operating climatically and intervening climatic crisis. Others will want to work with with Elias and Joseph Anastas on the way stone the carving of stone is actually a form of, of communal empowerment in the middle list. You will want to work with Dan Wood, revisiting the way architectural typologies and towers of buildings that are mixing uses become an opportunity to reinvent the way societies articulated. Others will want to work with other people that looking at the way the existing materiality of architecture can be mobilized and, but we have basically 10 very different studios, all of them incredibly intense all of them. We are very devoted to connect design with research as an opportunity to to turn the studio laboratory with notions future notions for architectural practices are are invented by each of you. Some of these studios will be working in groups some will be working in allowing or promoting students to work individually, but you will basically be in the lottery you will get in advance all the syllabi of these studios. In the first day of classes, you will go to a lottery, you will see a thorough presentation of each of the studios and then you will indicate what are your preferences what's your first option your second option, and through a student run process that is run by the representatives of the previous AD class, you basically will be assigned to one of your top options. And, and that is that you'll see it's very horizontal the studios have from six to 12 students and one or two instructors and a teaching assistant. It's a large team of faculty with a small number of students, so that there's the possibility for you to develop a very strong relationship with your peers and with your instructor to work together to do something that is very sophisticated, very needed, very innovative, and at the same time that represents what is important for you and gives you an opportunity to grow and sharp the kind of architects that you want to be. And then we have a second course that is Transcalarities. Transcalarities is a course that is composed by two parts. It's one part is a workshop in small groups with instructors that are experts on research, and that will have you basically get very rapidly. So one of the tools that you need to do high academic research, you will be introduced of course in how to do searches, bibliographical work, also experimental research use of media, but also you will be trained on academic writing, academic in the way to argue and how to build arguments and to provide evidences for it. So this part is very much helping you to very rapidly get to the level of high academic work and, and then the second part is discussion that I myself together with Jean Paul, Jean Paul Paulman curate, where we basically discussed in the course of the semester, more than 300 cases of architecture, and we do it in detail, which to a huge detail. And we, we basically, this is a huge opportunity for you to expand your architectural knowledge by, by knowing very well, the most important architectural designs of the last decades the ones that are shaping all the contemporary discussions. And this is really fun, we do that on Fridays in the afternoon and normally people go for drinks afterwards. So it's very, very, very, I would say heated discussions about the most important projects of the last decade so it's really fun but at the same time very, very helpful. Then we have arguments arguments is, it's very intense as well. Oh, sorry, I must say that for trans characters you have amazing people coming, we have Keller Easterling, Lydia Calipoliti, Mark Suramaki, people that have done, you know, let me show you some of the books for instance. Mark Suramaki will be working with us looking at he, he just launched this amazing book, and it's, it's looking at the way materialities it's now been applied massively to experimental projects across the world. And we will be basically looking at all the different lines to, to understand materiality, Lydia Calipoliti it's the expert on on ecological systems and again we will be looking from this 1970s to to nowadays, the whole. Hi, hi is experimentally, let's say innovative buildings in the in the terrain of ecology beyond the culture of sustainability of course and getting much more into the, the, the whole ambition of ecological thinking we also have Keller Easterling is coming to also work with us analyzing the way structures of market and capitalism and mobility, the forces of globalization have also been experimented through architecture in the last decades. And what I try to say is the transfer it is really the moment for you to understand how architectural design in the last decades, it's been advancing the possibilities that now we can anticipate for the future. Arguments is very different arguments is, is also composed by a part that is. Verso in smaller groups, and it's really, and then a lecture with entire class where we discuss together with with each way with a different visitor or guest speaker, and we basically invite the people that have produced the most important studies and practices on architecture for the last two years, very recent. And we half of them are architects. Half of them are people that were from other fields discussing architecture working with architecture. So I think that the work is very important because it's a worsen on interrogation. How to pose questions how to, how to basically destabilize destabilize knowledge. How do we find the cracks that allowed us to innovate in existing. And that we do in a very fun way also in the morning you basically meet with your instructors in small groups, and you prepare your questions prior to these meetings you have read all of you a text that is or a film or an exhibition you have consulted something that was previously sent by the by the speaker and then we meet all together in the in wood auditorium, and we have a very intense conversation with the speaker, we also have lunch there. And it's really fun because it's actually like a very active two hour meeting where we really interrogate the speaker find where the potential and the cracks of the discourses are and it's very very much also building the connection of the entire class to these discussions. And what we basically make sure is that all these lines of fire of these tensions that I was referring to the environmental engagement that colonizing the center and architectural accountable materiality and the cycle abilities of materiality, architectural as the articulation of the society at all the connections of the online of the offline the interspecies relationship, all these are basically dealt with in all these different courses. The course is incredibly different to each other, but they all have the, they're all mobilizing these lines of work and choir and innovation. So what is great is that by the end of the semester, both each of you becomes an expert on all these different topics, but also as a class, you have gained the culture of its own that that allows you to channel all your uniqueness and your specific sensitivities, individual sensitivities, your culture, your previous knowledge, but also connected with discussions that are shaping the identity and the capacity to work together of your of your cohort. The advanced science studios are very lively. They you are given for those that that are far and could not be with us in the last days. The studios are you're giving a place in the studio each group is actually together in one of these long tables and then you have places where you can meet as you see there is always very lively and very intense very densely populated. And it's really fun.  And but also this is if it's here when where you meet often with your instructors. And of course sometimes you have been absent there's a room that is where you're meeting and that, but so each group meets in different rooms but the, but you know the life of the studio is something that is incredibly beautiful. It expands into other facilities this is for instance, are making studio that is also a place that I think is is part of the student life in a very intense way. And also this is a place that offers jobs so if you have the training to use this or you can I mean the first day that you arrive you will be offered in the orientation, the possibility of getting training I would encourage you to do that as soon as possible so that you can fully do the making studio and even if you want to get the job there you're prepared for that you can write to the director even now if you if you if anyone wants to be considered for jobs is right now for this. We also work across campus and across the city and globally with experts, you will see that each studio is already producing connections with many experts that help you. But rather, whatever research you're doing in the aim of the of the studios. And what is very important is that whatever you do, it's at the center so we really are a student center school, and we really want to know what is that that is important for you and what is that that your work. So anticipating we are very very much paying attention to all you say to all you do because we know that the future of our world is resides there. And the way we do it is that you permanently present your work in front of a large community of faculty express visitors. Good discussions where basically you get to understand what else what's the potential of the world that you're doing in conversation by by explaining yourself and by by responding to questions and by getting comments from many others. We want to make sure that you have everything that is needed to develop your work is the presentation of a student that produce these huge other things and then as you present we're ready to have a bunch of incredibly clever people. Reacting helping you taking it farther clarifying what you're doing getting the tools that you need. And that's what we do all the time. In arguments we have, as I said we bring the people like Jack Halberstam for my fantasmac or Easterling. Laura Poitras and Henry Molke basically to have discussions you basically you meet in the morning I said in groups like the one in this photograph there will be like this to discuss the. groups like this you have meetings like this when you will be discussing together what how to interrogate the speaker and then the speaker comes and we have these very fun discussions. And this is this course that is also called arenas of design. It's also crucial because it's the moment in which you take the mic and have the opportunity to get as a class in conversation with me with by John Paul man with color is telling you to do the ability with Marshall Maki to interrogate architecture and with this I mean close environment so the, you know all these very very different architectural traditions that have been shaping architectural discourse and designing the last the case, we will be interrogating in detail in this in this to transfer this. The second and the third semester are very exciting. It's the moment that is very different, whereas the summer feels very intimate you take over the school you're the owners of the building. The fall is full of other people, which is actually great. And it's the moment that you melt in the studios, this also means that in the fall you have 20 studios from which you decide what are your first second options.  So that's great opportunity because normally the students bring all this critical knowledge that has been nurtured to the summer and that's a great moment for also let's say discussing it with the students that that have been in the school for two years already. So they can also help you navigate the school the university the city in a very intense way. And then you have a large pool of courses on history and theory and technology and representation courses that you can take. You're required to take one advanced studio one history and theory elective and one visual technology electives, but that's only the minimum, and we encourage you, you know the program allows you to take more courses without paying tuition. There's a limit of 19 points right to see that you can take without paying tuition, meaning that you can take more courses and I would encourage everyone to take as many as possible, because it's, it's a great opportunity to make the best of the pool of possibilities that is here in Columbia, you can also take courses across the campus. Sorry, before we get here, and the spring is very exciting is that the moment that we travel. So you will be traveling with the with your studio and doing field work engaging with communities across the world and doing a research that allowed you to elevate your the global impact of your of your work. This is also very important moment is when you're completing your portfolio. So this is crucial and of course we have on that and the school base for this term. We have a very large and very impressive pool of faculty. I mean we have probably a Stephen Hall, but not to me kind of front and it's not teaching but he's still here and there's all these different generations of very important voices of the in the field of architecture that have saved actually what we think architecture is now and that are the Benjamin in amazing work on ecology Hillary sample with moss. And Juan Herreros with all these corrections of typologies for them keeping with the thinking of the next steps of of parametric thesis and Lola been alone the director of the natural material lab inventing materials that are alive that they contain live themselves and that's a laboratory that they encourage you to be part of and be connected with It's very easy. But basically the work we do its work that it's not replicating the architecture that we know, but rather using complex discourse and technology to empower yourself as designers should do projects that other people could never do. This is for instance a project that is using machine learning to identify components that are really existing in buildings in New York and that could be relocated to increase the overall sustainability and energy efficiency of the city. And of course it's something that could not have happened 10 years ago and that is at the, at the avant garde of what can be done to the sensitivities and conflicts that we're facing now with intelligence with design, or for instance this award developed by again by a students that it's in the way different species relate to each other from human stomach to to the city to insects bacteria animals so that basically the notion of waste can be removed. And what is waste for one species what what becomes toxic for humans becomes the habitat of other species and, and that is the way to to mobilize nature in a city like New York. To basically eliminates its its impact by redefining the way humans relate to others. And this is for instance work that was done in the studio of bernard should mean studio. We have all these amazing people like Bernard that it's, it's shaped the way architecture is unfolded in less the case of course now it's 40 years since the construction of the lovely late Park in Paris that changed the future of architecture radically. And these are projects that his students are doing to to mobilize architecture as an agent for climate mitigation. Oh, this is for instance Michael Bell Studio Michael Bell is of course the, the expert and author of all these different books on materials on steel on glass, you probably know these books are the reference for material studies in architecture. And he's now thinking for instance of the way machine learning can transform daily life and actually cater to human agendas. This is for instance a studio with Amanda Williams and if a one of all that is looking at the tools of interior design as an opportunity to confront a structural racism. And that's something that was a Amanda Williams of course the, the brilliant artists and top artists, top world artists and that working with if a one of all that that was a very, very unique studio also. Well, for instance, these studio this work by Farah, a hurry and a graduate now that was very conscientious originally from Iraq and force migrant to Canada. And that she worked with the develop an architecture and infrastructure that would allow to reclaim the reins that were polluted. And so, so this is again like a way to mobilize architecture so needed. There's so much needed resources, appetite commissions for for works like this, and that we but also it definitely requires very advanced architectural development and across the world doing research studies associations. And that's something that as I said the school funds we have a specific endowment, the kidney endowment to work with this. And, and there's also opportunity for you to, to apply for for specific research for grants for specific research that you want to do that also involves traveling. But this is something that we do all the, everyone does, all of you will be asked to do this in the spring of 2024. All studies are, we're probably, I mean, I want to be pretentious but I think that we have probably the best team working with with visuals and representation led by Laura Kurgan, the, the, the, there's, we have a lab that is specifically working on these this is a work, for instance, that is developing G7 that was presented at the fence by any of the technology sequences run by low level alone and it's, but it has a large pool of professors that are experts on climate or materials on of interspecies and relationships, many of the things that I already mentioned, and this is where incredibly strong here there's so many amazing works that every year are developed by our students and also that support the way you can work in other courses and, and come up with with ideas that are addressing difficult, also critical questions of our time and, and, and we have also tools for you to self educate I mean we have workshops where we can get familiar with software but also we have tools like this is a skill trial, trials that allowed you to, to determine the kind of tools that you need to learn and to learn them online basically easily. And that's something that of course is run also by the, by the results that is a sequence. But this is crucial for us because we work with very complex information and come and conflicts and situations and realities. We want to make sure that we have that you have the, you're equipped with the tools to represent them to, to, to discuss them to work with them and also to produce new imaginaries new images new forums new aesthetics for architecture and this is again something that that is very proud of. We have among the AD graduates, some of the most important architects like Charles Renfro that it's right here shaping proximity to the shed that you know like so many important buildings that, that are bringing new imaginaries to what architecture can, can do, and how it operates and this of course, a very large number of possibilities and you will, you will decide which ones you, you take. But this is our core, and we also think that it's important to produce books. We have a publishing house, Columbia books on architecture and the city that is right here. We also we support students to produce publications and to launch them and to prepare them. We have writing workshops, we have events on writing. So writing is important for us books knowledge is important and we also want for those of you that have an inclination and an interesting in teaching in the future or you already teaching. You have teaching experience. We also have programs that allow for you to to to get a teaching experience in Columbia in G sub. And we offer the shapes every semester, but also, once you graduate you're offered the possibility of teaching in the in the first semester of the of the incoming class. You can be working with graduates from the program now in your studios will be teaching assistants, and you will have the opportunity also to teach in the future by applying to to an open call and there's 10 positions is normally, either at this moment or before normally those that have the, the interest of teaching they get opportunities to do that of course is to open cause not guaranteed but I must say that in the past, those that wanted to do it, I believe that they, they got an opportunity to do it. All these I want to insist is intended to make sure that that we render our discipline and design architectural design a way for you basically to to to move your sensitivities and to mobilize them to transform the world, let's say, and to to have a say in the in the in the future of humanity ecosystem societies. And that also reflects on your, the way that you relate to each other. The school has a large number of student groups that are very much specialized on things that are important to our students. You probably will find one that several that that are connected to your sensitivities to your, to your interest, but you can also do new ones every year we have new 80 groups of old school groups that are born, and the school supports them financially you can organize your lecture series, you can have guests you can do publications and that happens all the time and it's a great opportunity for instance, a few years ago, group of students launched the radio. And, and that became a great opportunity for for the class to be gaining a new voice I encourage you to look at the episodes you can find them in the, in our website, but this is very very, it's been a very very fun way for the class to, to work together. This is New York, and this is crucial for us. New York is probably the, as many people have claimed the most important laboratory for architecture in the, in the last centuries. And it keeps spinning each year is different each year there's new things going on here, and we work with the city very intensively. We actually work as the city I would say because of course our faculty are important people in the city they're connected to the firms, the laboratories, the authorities, the, the intergovernmental agencies, the museums, the cultural cold runs the artists groups, the underground networks.  And, and we also facilitate that once you graduate you also can continue being part of the city the ad program is a stem designated, meaning that you can apply to an OPT and allows, and it allows you to work in this in the city or, or across the country. And, and I mean being New York a place that has the most important architectural agencies or the intergovernmental organizations like United Nations so that has the groups of activism, also the proximity to many of the most important PhD programs. That's something that is very intensively used like the possibility of staying here preparing for working for a firm that you're excited about, or either independent or big or small, working many people with NGOs, working for intergovernmental organizations, but also preparing maybe getting a job that you're excited about while you prepare to apply for a PhD program. In an Ivy League institution is also something that we do all the time and we have many, many of our students are very proud to say that they're very successful when applying to PhD programs in either in a school or in other schools. So here we are in Avery Hall and where I hope to welcome you very soon.


Anirudh, Anirudh, waiting for Anirudh to confirm. Sorry, brother, you have to join now as the quiz progresses. Okay, so here we start. Three, two, one, go. So the first question on screen, read carefully and then answer. Okay, all of you will have to continuously put your mics on mute. Okay, so now they have changed, it seems. Okay, so the first answer is, okay, so still people are doing, do it.  Yes, they have redesigned it. They have changed many things actually. We are also trying to adapt with that. Yeah, so now you don't get to see how many people have already voted. So that's good. So you don't know how many people have voted, right? So just relax and solve, focus on solving the question. Yeah, less pressure, good. Okay, so first question was very easy. It was based on your last grade concepts on linear equations. Okay, so here is the, lots of people have made a mistake. Why, but lots of people have made a mistake. 28, right, why? Why did you, didn't read properly? I told you. So this was the question. There cannot be any distance between two intersecting lines. If you see, X is zero and Y is equal to eight are intersecting lines. They are nowhere parallel, okay? So X equals to zero is Y axis. And Y is equal to eight is X axis and eight, yeah. So what is the distance between this line and this line? Right, silly, right? So what is the right answer? So you have to check first of all which are parallel lines. So these are parallel lines and these were parallel lines, right? These were parallel lines. X equals to minus one and X equals to nine. So X equals to minus one is this line and X equals to nine is this line, somewhere like that. So total distance is 10. So this is not correct. Only Y is equal to five and Y is equal to minus three is. Any problem in this one? Yeah, so don't expect linear equations question to be only solving linear equations. You must have the concepts clear of Y and how do we study linear equations? Anyways, done, shall we proceed? So the first leaderboard, yeah, okay. Very good, so Aniket Gupta. Okay, so nice, here is the next question. All of you would have got your, yeah. This thing, there is someone called Volcani and I don't know who. Anyways, next question to you. Someone's mic is not on mute, can you just mute it? Otherwise I'll have to just change the window, okay. So which of the following doesn't represent a line? Take your time, it will require some bit of thinking. Sorry guys, can you hear me? Just give me a confirmation, can you hear me? Yeah, thanks. Okay, so here is, okay, fine enough. I hope all of you would have answered this. Okay, very good, let's see. Lots of people have made a mistake, yes. So D was a zero equal to zero form, so you should have identified that. So basics, struggling. This is clearly a linear equation, no problem, right? What is a linear equation? AX plus BY plus C is equal to zero. This is a form of linear equation where A cannot be zero, B cannot be zero, right? And A, B and C can be any real number. A, B, C are real numbers, right? So this is very well, very well satisfies this one. This one also satisfies, you just manipulate. This one also is a linear equation because this is 4.5X plus zero Y plus one equals zero. So this one is very much a linear equation. This one is not a linear equation. Why? Because this is zero X plus zero Y plus zero equals to zero. This is that form, why? You would have learned in ninth grade that one upon two minus root three is equal to two plus root three. If you rationalize, you will get this one. Okay, one minus two root three, rationalize. The denominator, you'll get two plus root three. So that means two plus root three X and one minus two minus root three X are same thing. Okay, so this is zero X. Similarly, two minus root three Y and two plus root three Y are same thing, zero, zero. Right, so they just get canceled. So hence this equation is of the form of zero X plus zero Y plus zero is equal to zero and this cannot be linear equation. See, in the very basic question, how many people have got it right? Sir, is it wrong to say that the reason is that there are irrationals in the denominator? No. What did I say? A, B, and C are real numbers. It could be anything. A, B, and C, there is no restriction on A, B, and C. The only restriction is A and B simultaneously cannot be zero. Both of them cannot be zero, right? And this was the only option where both A and B was becoming zero. So hence irrational numbers are allowed. Irrational numbers are very much allowed in linear equations, okay? Is that okay? Only the powers, power will be only one, right? The power of the variable has to be one, right? There is no ambiguity in that. Okay, fair enough. So basics, clear your basics. Okay, next question. Before that, the leaderboard. Okay, right? So, good. Nice, let's go to the next question. Read carefully and then answer. Don't jump on answering. Read each one of them, each of the options. Take time and solve. Read each question very, very carefully. Each question will have some bit of information. So if everyone would vote together, then we can proceed. Nevermind, take your time and try also to think, even if you're marked by others, or is there any possibility of other options to be true or incorrect or correct, whatever. Last 15 seconds, yes. So let's see how many of you actually got it correct. X axis is not zero slope line. Aren't all true? Okay, aren't all true. So those who have marked B, why did you mark B? Can anyone unmute and say? All of you can hear me, correct? Hello, are you able to hear me, guys? Oh, yes, sir. Yes, sir. Hello, can you hear me? Yes, sir. Yeah. Okay, guys, I think I am facing some issue. Just give me a moment. Just a minute. Who do I, yeah, okay, fair enough. Okay, yes, so here is the solution. First of all, so two lines may intersect exactly at one point. Yes, possible. This is very much possible. This is what we are learning at time to find out the solution, right? Okay, X axis is the zero slope line. What is the slope of X axis? Zero, this is very much correct, right? Right, and two lines, if at all they will intersect, they will intersect exactly at one point. There is no ambiguity in that. Okay, there are infinitely many solutions to a linear equation in two variables. Yes, wait a minute. So this is the, if two lines are not parallel, they will intersect at a point, not necessary. Not necessary. Why? Why? Because if you take two intersecting lines and just displace them in vertical direction. Okay, or imagine like that. In your room right now, there are two lines, right, which are one line at the roof and the other line is on the wall, like that. So when they are not coplanar, this is possible, right? When they are not coplanar, this is possible. Okay, did you get this second point guys? If two lines are not parallel, yes, obviously. Did I say this is 2D? Why, Anish, in which case it is not, Aditi, in which case there are not infinitely many solutions to a linear equation in two variables. I am talking about only one linear equation in two variables. Why are you assuming a Cartesian plane? Did I say anywhere? I'm just talking about two lines. Have we ever, are we even talking about any planes, anything we have given? No. Why are you assuming? I said which of the two lines is not correct. Okay. So two lines, if they are not parallel, need not intersect. Okay, when is that possible? When they are in two different planes. So imagine a line on the roof of your room and one line on the floor of the room, right? Even if they are not parallel, they will never intersect. Okay, so hence, V is the option. See, in the three very basic questions, we have not got into solution part of the linear equation so far. They will add some distance. Now who started the video? I don't require the video. Please turn it off. Yep, please, yeah, anyways. So, sir, they will add some distance. Never mind here, if two planes are coplanar, two planes are parallel, right? Imagine, as I'm telling you, imagine a line on the roof, another line on the floor. They are not parallel, let's say. And they will never intersect, is it? Sneha, is that clear? Sneha, is that clear? Yeah, Aniket, any issue here? Any problem? Anyone need to understand? Okay, let's move ahead. Okay, let's go do. So most of you did it wrong. X axis is very much zero slope line. There's no slope in that line. Okay, so change, shuffle, very good. R n single, keep it up. Next question on your screen. Someone has his mic on mute. Can you please request you to mute it? Who is this? Aniket Gupta, your mic. And yeah, Aniket Gupta, mic mute. So you know this is basically a question related to consistency of linear equations. It was very, very simple. Okay, that's nice. So fair enough, okay? So only 22, again. That means you need a lot of lot of practice. So I have to put another test on linear equations for all of you. Because, okay, so why? What is the rule for two equations to coincide? Two lines to coincide. It was A1 by A2 is equal to B1 by B2 is equal to C1 by C2, correct? This is the rule for coincident lines. The only one which satisfies is this one. See, the factor of 2.5 is there. Sorry, 1.5, yeah, four into 1.5 is six. Yes, correct? So this is the four parallel lines. Parallel lines, sorry, not parallel. Coincident lines, coincident lines. These are coincident. So people are making mistakes there. Please remember your rules, right? So if A1 by A2 is not equal to B1 by B2, then they are intersecting lines, just to intersecting, just to give you a, you know, recap. And A1 by A2 is equal to B1 by B2 is not equal to C1 by C2 is parallel lines. These are the three rules. Okay, please remember. So it was very simple question. I don't know why many people have not marked correctly. So here is the leaderboard. Okay, let's see. So some reshuffle, cool. Okay, nevermind. So let's go to the next question. All set, read the question carefully again. As I'm telling you, questions will be a little tricky. The wordings will be tricky. Oh, so option D has none of these. D option has come up, like some typing error is there. So D option is none of these. So now you are saved. So one out of three is correct. Again, infinitely many solutions. I just gave you the rule in the previous slide. Okay, let's see. If time is too much, then everyone should get it correct. Okay, see, let's see. See, even if with 100 seconds given, all of you have made the wrong. Most of you have made it wrong. What is the point of having lots of time? Yep, all of you got it, correct? How many? See, why? All of you have marked six. What was the question? I told you, read the question carefully. How many values of C? They are not asking value of C. They're asking how many values of C are there, right? And all of you have marked the value of C, right? So hence the questions will be right like that only. So you guys don't understand. I keep on saying, I keep giving hints. Keep giving hints that, you know, read the question carefully, read the question carefully, but no. See, you got trapped, right? This is how you will get trapped. See, both the options are there. These are the real exam scenario. Both the options will be there. You will be solving very easily. System of equation has infinite many solution. Y, six upon 12 is equal to three upon, what? C, is it? So you will find C is equal to six. Okay, C is equal to six. And then you will see the option. Oh yes, it is there. Click it and go. But then question was, how many values of C are there? So only one value is there. So answer is A, clear? Understood. Learning is learning. My mother tongue is Hindi. So I will give you one. All of you would have read Hindi sometime in your life maybe. This, do you understand this? Right? Yes, one more. Correct. So hence the, Ananya you understood. Saadani, Adi, Durgatna, Adi. So you guys are on that track. It's like a cricket match. If you take away your eyes from the ball, gone, bold, right? And lost the match. So hence concentrate. And these are the types of questions which will be there to test your temperament more than C, only 12. This is so surprising, right? Anyways, see lots of people have got it wrong. In the leaderboard itself people have got it wrong. So that shows that where is your focus. Anyways, let's go to the next question. Again saying, read the question very, very carefully. Again the same rule, but I don't know whether again, you are paying attention to the minute details. I hope this time also you will take time and then solve it. So why time has been given is solve and check again whether you have done it correctly. If option 1.5 was there, many would again make a mistake. Okay, so you understood the theme now, right? Questions and knowledge base will be very a sound. You will be knowing everything. Very rarely you will miss. It's not Olympiad question. Olympiad is where you don't know the question only. How to solve it. But in most of the competitive exams it will be like, you know it, but you would. Okay, so here you see again, lots of distribution happening. Again very few people are able to base it. I don't know what, okay.  Okay, so hence if you see, this one was k plus one x. So you have to simplify this first, right? So hence it is k plus one x, right? Minus three y plus six equals zero. And the second equation is three plus k x minus six y plus 15 is equal to zero. Isn't it three? What is three? K is equal to one. K is one, right? So you have to do what? K plus one by three plus k should be equal to three by six. Okay, three by six. So what should be the value of k? K is equal to one. We'll satisfy this. Isn't it? You can, you can solve, right? Six k plus six is three nine plus three k, okay? So that means three k is equal to three. So k is equal to one, right? So when I was framing this question, I did not put this minus x on the right hand side. I was putting it zero. So hence I put minus kx also here. Yeah, understood Aniket Gupta. I told you, this is what will happen. This is exactly what is going to be there, right? So hence now you know the purpose of centimars. Anyways, it will help if you now curse yourself that, hey, when will I, you know, set it right? Okay, so eat one chapati lesser today, tonight, next. Oh, miss clicking can happen, Surya. So really, really can't help you there, buddy, sorry. So here is the new leaderboard. Okay, let's go to the next one. Again, for God's sake, read the question thoroughly. Read the question thoroughly. This should be done by all. So hence if everyone votes, so we can proceed. Just confirm once you're done. So I'll request all of you to mark your answers if you're done, but again, spend time. That would be better. Questions would be easy, but they would be tempting you to do wrong activities. So hence the only idea is to improve your, improve your, what do you say, consciousness. But this is very simple question, no? Very easy one. Okay. Okay, very nice. So, so why is this session conducted is to give you a taste of unconventional approach towards problem solving. So don't really bank on only your, you know, Adi Sharma's and RS Sarval's and NCRT's for the basics. Okay, here is the explanation. Very simple it was, right? So AM is equal to BL. So AM is equal to BL. It will give you A by L is equal to B by M. And BN is not equal to CM will give you B by CN, right? CM, yeah. So B by M is not equal to C by M, right? And this is possible only when they are parallel lines, right? So it's basically satisfying A1 by A2 is equal to B1 by B2, but not equal to C1 by C2. Isn't it? So when that is true, then it has no solution. Clear? Any question here? Any problem? Anyone? No. Let's move ahead. Okay. Lead a board. Hmm, most of you did it right. Very good. Okay. So let's go to the next question. Okay, I don't know if you are able to see this. So let me show you here. Which of the following graphs represent the line two X plus four Y equals to eight and three X minus four Y is equal to 12. Now I can't give you plotting a graph question here. So I have done the other way around. I have two graphs and then you have to find this out. It's a bit so that I could know who or how. Okay, so how much time is left? 20 seconds. What is the code? Someone code is 80548. Okay. So this was, okay. Most of you have got it correct. That's nice. Yeah. So how to solve this one? Again, it was very, very simple. No time consuming. It will not be time consuming at all. That means, no, that means you have not implemented it properly. How to, you know, very easy. See, two X plus four Y. I hope you have not solved these equations. No, you don't need to do anything. Put X equals to zero. What is Y? Y is two. Yes, that's it. Correct Sneha. So X is zero, Y is two. So first point of the first line is zero comma two, right? Next put Y is equal to zero. So you'll get X equals to four. So four comma zero is the another point. So these two points are on the first line. There are these zero comma two. Zero comma two is here. This one and four comma zero is also here. So this one option is there, definitely. None of the other options are. This one also is there, right? So out of these two only have to check A and B. Okay, then go to the next question. Next equation, three X minus four Y is 12. Put X equals to zero again. You'll get Y is equal to minus three. And put Y is equal to zero. You will get X equals to four. So four comma zero and zero comma minus three are the other two points. So four comma zero is here and zero comma minus three. So A is the answer, how much time? So the question need not, you know, you didn't require to solve them. But you have to, Momita, you can do. You can do, but then one has positive, one has negative. So don't you think you can get stuck here also? One has positive, one has negative intercept here also. So there are more such options, Momita. Momita is saying can we check these slopes or Y intercepts and one has positive. Okay, so you can eliminate. You can do that. Oh, I was thinking of slope. Oh, you're talking about Y intercept. Yes, you can do that. Yes, you can do that. Yes, you can do that. You find out the, right? Yeah, that also can be done. So for precise, you know, points. So if only A has Y negative, okay? So you're finding Y intercept. So Y intercept is found by putting X equals to zero in both. So what you are doing is put X equals to zero in both. So X equals to zero if you put, for first case, Y is two. And for second case, Y is minus three. Yes, the only option is this, correct? You can do that. Yes, that was faster than. Nevermind, so let's go to leaderboard. Okay, so this is the new standing. Nevermind, let's go to the next question. Require you to solve it. This will require some solution. Some solving has to be done. Very simple question, I think. This is a typical question. But then yes, I have not asked you the direct solution. I have now I want to also check whether you have retained whatever you learned in previous grade or not fair enough. So I think most of you would have got it correct. Oh, again, some spread is there. Why in this, what was the problem? We had to just solve it, right? So use elimination and solve, that's it. Or if there is any other method, let me know. So it's very two X minus Y plus three is equal to zero. And this was three X minus seven Y plus 10 equals to zero. So what I'll do is I'll multiply this equation by seven. Correct, so that Y can get eliminated. So 14 X minus seven Y plus 21. No, how are you doing that? How are you doing that?  So subtract it, you'll get 11 X, 11 X, and plus 11 is zero, so X is minus one. So when X is minus one, you can find out Y.  So which is one. So minus one and one, how much time does it take? So minus one and one is in second quadrant. So try drawing graph when the graphs are complicated. For example, if you have now learned polynomials also those who have learned, if I give you this, Y is equal to X square minus three X plus one equals to zero and Y is equal to two X square minus five X plus two equals to zero. Let's say these are the, sorry, not equal to zero. These are the two graphs. Then where, then you have to plot, you know, then exactly, you know, one way is to plot the graph and check, right? But then here it was linear, simple, 30 seconds. Never mind, but still most of them are not able to get it. So that's concerning. See, in the top 10 also there are lots of shuffling happening. So that means you have forgotten now a month old. So we discussed linear equations in the very first few weeks. So hence I think you have forgotten many things. Anyways, next question. So this, these kind of sessions will help you. Results are here. Okay, never mind. I hope you have done the basic calculations properly. Okay, so very good. So three, two, and one, let me see how many of you have. Okay, so still lots of people are getting confused. How many of you got it correct? Just give me a confirmation. Anyways, I have the result, I will check back. Okay, very good. Very good. So even if you don't know this particular form, you could have done it very easily by using trigonometry maybe, that can come into, you know. So what is this line? First of all, let's draw this line. So four X plus three Y is 12. So if put X equals to zero, you will get Y as four. So zero comma four, so this is one point. And if put Y equals to zero, you will get X as three. So the other point is this one. So the line is like that. So this is three, this is four. Isn't it? And you have to find out this perpendicular distance P. Okay, so clearly let's say this is theta. This will be 90 minus theta, so hence this will also be theta. I hope this is understood by all.  Ha, that is also correct. That's also, so half into, that's actually easier. Half into four into three. So hypotenuse is five, no problem. Half into five into P. Area will be same, correct? The two ways of doing it, one is area method. This is area method. Find out the area. So area is half into four into three, base into height. And hence, yeah, that's also cool of guessing. So hence you will get P is equal to 2.4. There is no, no tau, what does it mean? Ah, right, so hence be careful. Correct, advertise has a point. Are in, there is none of these also. So hence you have to check the answer anyways. Okay, so 2.4 is one way of doing this is like this. Another way of doing like that would have been three upon P, or P upon three. P upon three is cos theta. P upon three is cos theta. And P upon four is sine theta. Check from your trigonometry, right? Correct, no?  Square and add. So P square by nine plus P square by 16 is one. Why? Because sine square theta plus cos square theta is one. So this is another way. So you'll get P square common. One by nine plus one by 16 is 25 upon nine into 16. I'm doing the fast calculations faster. So this you can figure out yourself. So P square is equal to nine into 16 upon 25, isn't it? So P is three into four by five, which is 2.4.  Or no, you don't use this one. You'll get complicated results. So there is another, which we had probably, area method again, yeah. See area of, so let me complete the third method first. So third method, which I'm talking about is there is a typical form of a linear equation where you can convert it. Yes, how does it, how does this form communicate? So there's a, you know, it's called the perpendicular from the origin and the line form. So there's a typical form where you can convert any linear equation, which you'll learn in next year, coordinate geometry. So that way, that method I'm skipping. I'm just telling you the area method once again. So area of the triangle, which triangle, A, B, C is what? Half into A, B into B, C. And this is also equal to half into A, C, which is hypotenuse into the P, perpendicular P. So what is P? Half, half goes. So P is simply A, B into B, C upon A, C, right? So three and four, you knew. So by Pythagoras theorem, this was five. So apply three into four by five, 2.4. Clear? Alisha, right? So I hope this is clear too. Everyone, let's go to the leaderboard and then the next questions. Okay, okay, okay, okay. So many people didn't get this correct. Why? And you took so much of time also. Very good, next one. No problem, next question. And Rose downstream at 12 kilometers per hour. I know, I hope you know what is downstream. So going along with the stream and upstream at eight kilometers per hour, that is going again, the stream. He doubles his speed in still water and rose 72 kilometers upstream. In T minutes, T is equal to last 10 seconds. I hope this should be not that tricky. Fair enough. So let me see how many of you have, today I'm getting a lot of mixed responses. I don't know why. So there's no clear, but people are just guessing or why people have marked A or C? So D is very less, why can ignore, but A and C, why? Okay, so how many of you could not solve this in time? Time was lesser or what happened? Anyone? Out of time, okay. Anyone else who struggled in this question? Any other struggle here? So it was very easy question actually. See a man row downstream. So let's say V1 is speed in still water. So I told you, right? Immediately after reading the question, so we read it, a man rows downstream at 12 and upstream at eight. Obviously upstream will be lesser, so verified. He doubles his speed in still water and rose 72 kilometer upstream. So I need to have upstream speed. No, you can't, you don't need to assume anything. So speed of initial still water, V1. V1 is the speed in still water. V2 is speed of water itself, right? So V1 plus V2 is 12, correct? And V1 minus V2 is eight, big deal, right? So sum to V1 is 20, so V1 is 10. Correct me, V1 is 10. Then V2 is two, he doubles his speed. So doubles means 20 now. Doubles his speed in still water, so he's now 20, but he's going upstream. So his speed will be 20 minus two, 18 kilometers per hour. And he covers 72 kilometers. So how many hours? 72 upon 18 is four, four hours, no problem. Yep, so 72 by 18 is four, right? So four hours, 240 minutes. Okay, so 240 minutes is the right answer. So 21 of you. Anyone who didn't get this? All clear? Actual speed much faster. No, I mean sir, here we can assume actual speed much faster. That's the question. So is the real speed average of upstream and downstream? Yes, so for any V1 minus V2 is A, let's say, and V1 plus V2 is B, right? So if you, two V1 is A plus B, or very good point, A plus V by two, arithmetic mean. Not visible, what is not visible? Who? Am I, am I audible, visible? Guys, yes, Aniket, yes, I am very much visible to everyone. So, yes, Anirvan, oh, board, oh, sorry. Yes, so good point raised by Momeda, that in case of, but only in case of constant velocity, constant velocity, Momeda, if there is some acceleration happening, then you can't see it say that. Okay, so hence upstream and downstream. So, yeah, so the still water velocity is nothing, but the arithmetic mean of upstream and downstream velocity. And the catch was that I had given you upstream. So hence you have to subtract this two again, which many people have missed, and hence the problem. Okay, next. Oh, out of 10, five people got correct. That's surprising. Okay, next, last one. Question of, last question of the day. The largest angle of a triangle is twice the sum of the other two. The smallest angle is one fourth of the largest. The largest angle is, trial and error is faster. Actually, this question need not require any solving. This question need not require or didn't require any solving. No solution was, no solution was, no solving was required, actually. The first line itself, no, you don't even look, you know, so most of you have got it correct, actually. So you don't need to look at the options also. So this is a useless information. So I have deliberately added that. So you have to identify which one is useless information. So the smaller angle is one fourth of the largest. We'll take away some time. Some people would have been involved in taking X and Ys and all that. This itself was over. So largest angle of a triangle is twice the sum of the other two.  And X is given as two Y plus Z. So even if you have taken this for the sake of doing it, so you'll get X plus this Y plus Z can be written as X plus X by two, 180. So clearly X is 120 degrees, okay? So this one is the, so there will be, what is the learning? Learning is there will be questions which will give you unnecessary information as well. It happens in most of the competitive exams. So hence, whether you are able to screen off or siphon or, you know, shift through the data, right? The largest angle is, many a times people will go back to this again. Why, if the largest angle is asked, why is this statement given? So it also checks whether you are confident enough of whatever you're doing, right? So this is the correct answer. Thankfully, most of you have got it right, but not all, that's surprising again. But anyways, yes, so that's the question. That's what the intent of the question, Aryan, so that the examinee get confused. So they will deliberately try to confuse you because otherwise, anyways, so understood all these questions, question again, yeah, here is the question, right? All these questions were deliberately made to trap you. Trap in the sense, why do I keep trap? You know, why do I do this? Not that I get some sadistic pleasure here, but you guys, from my experience, I know most of the errors happen at this stage only in the sense last stage, calculation stage, not reading the question properly, and overconfidence, yep, and not checking your answer again and tempted to, and especially in MCQ based exams, what happens is, you are tempted to bubble that round circle over there. Temptation is quite high, and you have to learn how to control that temptation as well. And hence, by practice only, it is possible. So hence, every centaur with me or with anyone else, we will try to fall, we make you fall in the trap so that you learn, learn, learn, and eventually come as a winner, okay? So don't get disheartened if you are making such silly mistakes here, but then do please learn and raise your consciousness more and more. Fair enough, so the last leaderboard of today is this, and let's see who was the person who got the first position. So I think Aniket Bhukta retains his first position followed by Aidan Aditya and then Suresh and then I, then Arun Singhal, Vivao Anish, Pamesh and Mahabal. Very good guys, keep it up. Keep the learning intact, congrats, congrats to everyone, but you could not get anywhere closer to 12,000. So that's something also is, the total marks was 12,000, you got around 8,000. So around 66% of marks you have got. So hence, think about it. Okay, very good guys. So let's meet again. By the way, next week we are going to conduct one geography center, maybe on Monday itself. So be ready, right? Geography, first chapter. You have to just read through. Yes, it's on mentee and it will be an open book quiz. So you can keep your book with you, okay? Keep your book with you. 10th grade, first chapter geography, which is going towards NTSC, okay? So hence, yeah, like this only, like this only. It will be like this only. So you will be having the book soft copy, first chapter, whatever it is, check it, okay? So keep the copy, keep the copy of the book with you and you are allowed to see through or go through the books, go through the internet, Google it, whichever way. And let's see if you can solve geography problems then, okay? On Monday. Bye, take care, enjoy.