So today I will speak about Dectoral Tychography. So as you say, I'm a guy more in a spectrum of the range of the optics. So for us in optics, when we speak about images, we have a great advantage, which is that we have this microscope objective, which is a great component. So when we are dealing with images, what we do is that we just use this kind of powerful lens to form an image in the plane, which is called conjugated. And we know in textbooks that we have a resolution which is related to the numerical aperture. And what is important to understand is that in this conjugated plane here, we have an intensity. We have a light field of light, which is actually a magnified field, which is similar to what we have here in the plane of the object. But since we are only measuring the intensity, we have many the amplitude information about the light and we lose the phase information. So thus so far, I mean, microscopy had a great success for imaging. But what is sure is that it has this weakness, which is this inability to image the phase. So this is basically what was interesting for me when I started to hear about Tychography is that this ability to actually get the phase information that could actually be extended, of course, to the optical range. This sensitivity to phase is very regulatory for different kind of phase objects. For instance, specimens, which are more or less transparent, would give a very poor contrast, but also focusing components such or light deflectors and even more objects, which we call holograms. So there are many approaches that allow to image the phase in optical regime. So there are tricks. One of these tricks is so-called the phase shifting interferometry, which is also called digital holography. I mean, this is a big family of systems. And basically the idea to retrieve this phase is to make an interference between the field that we're interested in with the reference one. And here we on the image plane, we get an interference pattern in such a way that the intensity that we measure encode the phase information. So there are many approach that use this to get the phase information. Another one I would like to mention is the weight front sensors that you have illustrate here. So it's a component that is able to probe actually what was the weight front and how distorted it was. And there are many interesting applications that have been even in the biology with this kind of device, which is, I have to say, more adapted where the phase modulation is very weak compared to what we present today. And as you see, these techniques need references, which could be a very important drawback. And I have to say that these techniques also gets very complicated if it deals with polarization. So this is basically a very short introduction. The outline of my talk will be the following. First, I will give you a very short introduction to typography because I guess the audience here is very familiar to this approach, but I will spend more time to speak about polarization. And then I will show you how to imagine a kind of challenging specimens, which are natural one, which are the bio minerals or artificial one, which are metasurfaces. I will also show you that it could be also used to image light. And to finish, I will give you a short discussion for you to understand in which situation it's important to go for vectorial or if it could be doable to remain scalar.  It's a computational microscopy technique. So you use this coherent illumination. What is important is that you need to be able to model this as with a multiplicative model, which means that you cannot have multiple scattering. So I mentioned this because for us in the optical regime, it could be a very strong limitation because some samples scattering a lot. And that could be a limitation for applying typography. So under this assumption, you could model the exit field as a multiplication of the illumination times the objects. And what you record is, as you know, the far field intensity pattern that you only record in intensity under good conditions, which means a scanning and an appropriate overlap. It has been shown that you could reconstruct the objects in phase and amplitude and the probe that has been used to probe this object. So here I insist on the fact that when you look at the retrieved maps here, so we have this probe on the left and you have the object on the right. So both of these maps are a map, which I call scalar because at every point of the map, I have a single complex number. And this is why I use this color map to plot the value of this complex number everywhere here on the plane. So that brings me to the point where I will speak about the polarization of light. So to imagine to understand what is the polarization, you need to remember that you have seen in textbooks that when you want to solve the Maxwell equations, you get that you could have a wave. And that wave is due to a field that oscillate in the transverse plane. So here this is a picture of an oscillating field and you have to imagine that this is a wave that is propagating perpendicular to the display. The general solution is the one that I've plotted here. So it looks so it's actually the red arrow that corresponds to the electric field that is a solution. And this is oscillating at a given frequency. And so you see that he described a nice ellipse. So it's a general solution and this ellipse you can decompose it into as the sum of an oscillation of the field in the X component, for instance, and the oscillation of the field at the same frequency along the other direction, which is the EY. A nice way to describe this is not to describe this real quantity, but to switch to this complex amplitudes that you see here. So you have here complex numbers and you took apart here the time dependence and the dependence along the propagation distance. So the idea that you have this state of polarization, you have different ways to actually represent this to model this so to quantify this. So one approach is the famous Stokes vector. So this is this vector which is made of four real quantities and which are calculated with the definition I give you here. So it's something which is very used in imaging because it's real quantities so it has definitely been designed for measurement. And what you see here on the definition of this and you see this time average and space average also about this EX and EY components that tells you that this property of polarization, it's linked to a coherence between the EX and the EY components. So for you who are maybe familiar with the notion of coherence, which is usually a phase relationship that you can have between the light at different places along the beam or transfers to the beam. Here it's a matter of coherence between the X and the Y component of the beam at a given place. So another way to define this property of polarization is the so-called Jones vector, which is simply the two complex quantities that you have here in the description of the field. So these are complex quantities. I have to mention that this description is only valid for totally polarized light, meaning that I need to have a clear phase relationship between these two components. But this description compared to the previous one has a great advantage, it contains the information about the overall phase. So to illustrate what I'm saying is just to say that actually the Jones vector tells you about the state of polarization and exactly where you are at a given time, whereas the Stokes vector only tells you about the state of polarization, but you have no information about the phase of the field at that time and at that location. So this is why in the rest of this talk, I will stick to the Jones vector description of light. So when you have this illumination, which is then polarized, I need to describe it with a Jones vector. So this is my illumination here on the left. Here I choose a linear polarization. And when this will interact with an object, general, I could have an exit field that could have a different state of polarization. Here I put a elliptical polarization. So if I want to describe the properties of my objects, then if since we have a multiple assumption here, it means that my object need to be described by the so-called Jones matrix, which is now four complex terms to describe every point of my object. So I ask you just to remember that the light is described by a vector two quantities, whereas the object is defined by a matrix four complex quantities. So now we have a Jones matrix that encompass all the optical properties you could have in the object, meaning, of course, the anisotropy related quantities, which could be retardants, linear or circular decrysms. So this is the ability to absorb light depending on its state of polarization. You could also have weird phenomena like optical rotatory, porous, etc. And it's also encompass isotropy related quantities, which are basically the absorption and the phase shift induced by an object. So we have established a couple of years ago that we have proposed a way to actually include this in the typography scheme of measurements. It means that instead of having one map to reproduce the object, we need to find four complex quantities for this. So the Jones matrix, and so this could be done by using set combinations of polarization. So it means that we need to introduce here the linear polarization of the probe together with the linear analysis of the output field. So we have several combinations here. So using nine combinations, we record a much higher quantity of data and using an iterative vectorial tachographic algorithm. We have shown that we're able to reconstruct the objects, which is so these four maps of complex quantities together with the eliminations. So we have here three sets of eliminations. Technically, this is made so we are in the microscopy in optical microscopy. So this is made in a simple inverted microscope. We have here an elimination on the top. The object is placed here. So the expensive part is here this scanning stage. We have here the microscope objective, which is forming here an image. And this is not the place here where we put the camera. We put here a field stop. So small aperture and we put the camera further at the distance about 20 centimeters to have the far field intensity, which is recorded for the tachographic scan. Of course, here we have a couple of components to control the polarization of the light before the objects and after the microscope objective. So this same setup is relatively simple. Now, just a couple of words about the algorithm. So we start like classical tachography with a guess. So the guess here is just that we have no object, meaning that it's like a diagonal matrix. So the first term is one here you have a map of zero, zero and one. We have a criterion that we need to minimize. So we try to minimize the difference between the square of the antenna, the square root of the intensity as it is calculated with respect to the one which is measured. And so there is an iterative algorithm where we do the propagation, calculate the far field, introduce here the information coming from the experimental intensity, inverse the propagation and update with appropriate gradient here. And so this will produce the results. Okay, so now I have described this method. I will show you what it gives on the rather challenging specimens. So the first I would like to describe is the one that we have studied in a group for years now, which are in the topic of biomineralization. So this is a piece of the oyster pink tada Margaritifera. So it has, it is very challenging in optical microscopy, because it's a rather challenging object. It is not very flat is rather thick, by the way, and it's made of prisms that you see here. It's something like have a size of the five to 10 microns. It is not completely homogeneous. And more importantly, and so that's really interesting for it's an isotropic. So this is what you see if you place that object between crossed horizons. And basically you have to interpret this image as where it's black. It's mean that the polarization doesn't change. The light was blocked. And this color, it's mean that you have a state of polarization that was changed by passing through these prisms. So here there are prisms of calcite. So we have performed pictorial technology measurement on this kind of sample. We have obtained these Jones maps. So we see these four maps here that correspond to the solution. And for the next slides, I will focus here on the rectangle which is here to show you what kind of structural information we could have out of this Jones matrix. So first, what we could have is the map of returns, which is the one that we would have seen if we have put this in a normal transmission microscope. We have here the map of the optical path things. So it's related to the thickness of the prisms and where you could see that from the left to the right, there is a gradient of thickness and actually every prisms behave like a small bump that we could hear monitor. And it's important to notice at that point that neighbor prism have very similar thicknesses. So you will see that it's important for the rest for the next slides. Here we have an isotropy related informations. And this is the fast axis orientation that tells us about the orientation of the crystal axis within the plane and the retardance that tells us more or less how much the crystal is an isotropic. This is kind of information we could analyze the more deeper way because here, as I told you, we have the two kind of information I to go back to the slides here. So what is very important here is that we have together something which is an isotropic information about the thickness of the object where we also have an isotropy information about the crystal itself. So that means that here when we see, for instance, that we have crystal of very different retardance, we know from the previous measurements that it's not due to different of thickness, but it's only due to different of axis orientation. Okay, so a cartoon picture that I could have is that these two have a different retardance, but it's not because one is thicker than the other one. The more appropriate interpretation is just that one has its axis more tilted with respect to the other one. Okay, so this is very valuable information that we could have that show us that depending on the present we are observing, we could have information about this C axis or it is oriented in space. Okay, and numerically, this is made this way. So we have the optical path length that is given by this index time the thickness. So knowing the index, we could get the thickness and knowing the thickness out of the retardance here, we could get the birefringence. Okay, in calcite, so it's a bit technical, but I have to do it quite quickly. In calcite, the index is defined by this ellipsoid of the indices in 3D. So having this effective retardance here tells us about how the crystal is oriented in space with respect to light with this kind of dependence here. So that we were able then on this kind of crystal to build these maps where you have here a color that tells you how the axis is tilted with respect to the plane of the sample. And if I look at front and these two crystals here, I see that this one is very homogeneous. This one was not homogeneous in terms of retardance, but this is just because the C axis was slightly, I mean the tilt of the axis was slightly changing in the cross section of the crystal that you can see here. So just a couple of words about other analysis that could be done. Knowing the Jones matrix helped us to calculate the Eigen polarization of the material. And this tells us, this Eigen polarization tells us what kind of polarization are able to propagate without be changed within the crystal. And there's a very known property, which is that if this Eigen polarization are linear, which has the lower left one here, it means that I can describe my object like a single bifurcation material. Whereas if my Eigen polarization are ellipse, it means that at least I have a super imposition of several crystals that are misaligned with respect to the others. So more or less, it means that if I look at this Eigen polarization at every point of the prisms, in positions where I don't have lines, where I see ellipses, I can tell. So this is the case here in this part of the prism, this part of the prism that I have singularities in the structure of the crystals that defect in depth. Okay, so this is a kind of very detailed structural information that is provided because we had the possibility to have together the phase and the retardance properties of the crystal. Okay, now I will move to more artificial objects, which we called metasurfaces. So metasurfaces are devices, components, optical components that are based on the structuring of a material at a scale which is smaller than the wavelength. So you see here the kind of material we're studying. This is a collaboration with a group of Patrice Genvay in Valbonne, who is an expert in the study of these metasurfaces. And so that kind of objects have a global response to light and the way they are manufactured or the way they are oriented, their thickness, et cetera, introduce specific phase shift or change of state of polarization. So that means that this kind of small object for us in optics are quite fascinating because this is kind of an optical toolbox, meaning that you could really tailor the optical property of any components. So here I will show you a couple of examples, but typically the kind of thing that could be done is typically a component where you illuminate that component and display you an intensity pattern here where every part of the pattern has an appropriate state of polarization. Here you have another one which is quite fascinating. This is an object. When you look on this surface you see a figure here with your face. And when you look in the far field, so on the holographic projected image, you see a pattern which has nothing to do. And all this is made on appropriate polarization. This is also an example of how to use this to create weird beams of very weird special distributions. So imagine a meta-surface. It's a challenge in terms of optics because we have to map quantitatively both phase and polarization property. So as you have understood, this is something which is for which vector ultra-graphy is very appropriate. So the sample, I mean one of the interesting sample that we have studied is the most recent that we have made with this group is a pattern in such a way that when you illuminate this pattern, with horizontally polarized light, you get an intensity that is homogeneous. So you expect to have projected intensity that will be a square of light, whereas actually the polarization property within this square will have different patterns, meaning that if I plot a map of the orientation, I should see this shape whereas if I plot the ellipticity of my light, I should say this rocket here. So this is a sample that we have put on our setup. I show you here the Jones map. So more or less, so you see these four impressive maps. So it looks very structured. It is not very impressive because you have to keep in mind that this is a hologram. So if you look closer, it looks like this, but it's this kind of picture is not very informative. But to show you that what we have found is actually the real object, we could use the property of having this Jones matrix, meaning I told you that this, the great advantage of this Jones matrix that we have the possibility to know exactly the phase, the overall phase. So it means that if we use this, we have the property possibility to check how the field will actually propagate after that object. So this is what we have done. So from the reconstructed Jones matrix, we have made the following simulation. So we multiply by a given illumination, but we will get a resulting vectorial exit field that we fully propagate to a monitor, what will be the vectorial far field of the holographic image based on or measurement of the Jones matrix map of this metahologram. And so this is what we have done. So I show you the lights, how it's the way it propagates. So you see that depending on the distance which is displayed here, you see the square of intensity which is forming. And you see also that the map of orientation and ellipticity displayed the desired shape. Okay. Okay. So here I focused on the imaging objects, artificial or natural, but I would like also to show you that it's possible to imagine light fields and there are some topics for which it's a very critical. So now so far we had so far we had several illumination, and I have shown you that we could image any an isotropic or isotropic specimen here by mastering the polarization before and after. And for this kind of measurement that I have shown you before the only knowledge that we need was only the state of polarization of the illumination. So we only needed to know that it was actually linear with the angle that were desired. We have shown that it's actually possible to use an unknown illumination beam that you see here. And to analyze it, using the same vectorial tachyrography setup, and the only constraint that we have is to use here an object that could be that needs to be only non-barreffringence.  And with a non-barreffringent and scattering specimen, we could use any vectorial light field just by using three analyzes. Okay, so here if you compare here the picture here compared with before, before I had I retrieve an object and three illuminations. Here, what I will retrieve is the object and it's important to check that I get to retrieve the appropriate object that I knew before, and that's a guarantee that what I get here as an illumination field is correct. And so the illumination field that I get, as you remember, is a Jones vector, it's a map of Jones vector. So it's again these two components that will be EX and EY, map of each represented with this color code here. So the first one that we have obtained was the analysis of a radial polarization. So this is a kind of beam that you can do by using a so-called S plate. So you illuminate this with a circular, sorry, linear polarization and we get a beam within which the polarization is radial like this. So this is the kind of intensity, a map of field that we get for EX and EY. And here you have to understand that I have all the necessary information to understand how this beam behave. So it's not very easy to understand here when I just show you this very colorful image. So to show you more like what it looks like, it's better to actually make the field oscillate so you could really see here what kind of beam is this vectorial beam that you see here. And what you see here in particular is that it's not a perfect beam, so an experimental one, but you see any way that you have a radial polarization. You also have some regions in which there is a weak elliptical polarization. And there is also here a weak wavefront curvature. So you see that it's a quite precise tool for characterizing complex beams. Another kind of beam I would like to mention is this phase vertices. So which is also called angular momentum, orbital angular momentum. So here you have also again, so it's okay just tell you a couple of words about how it's made. So it may again with this S plate, but you have to eliminate it with a circular polarization and the output after this is a field which is quite difficult to understand. But just here, this is the wave, the phase front of this beam is twisted like this. Whereas here before, if I would have put the phase front, I would have put disc that propagates along this distance here. So here you see it's much more twisted. And here this is the map of the EX, the map of the EY. And again, I'll show you how it behaves. And so you see that we are able to describe the field in its entire property because we see different kind of things. First, we see that it's circularly polarized lights, as you can see everywhere here on the beam. And in addition, there is this orbital angular momentum, meaning that the phase is actually rotating. If you look at where the field is, let's say on the right, the portion of the beam where the arrow is on the right is actually rotating like this, which is the characteristics of this orbital angular momentum for a beam. It's also possible to analyze very completely arbitrary beams. Here this is a speckle that we have made by using a scattering field. So we got a speckle and the image of the speckle is like this. So we've seen this grain of light. And as expected, you see that the state of polarization is the same within any grain of light, which is something that was expected by the theory. And you see there is no phase correlation between grains. So that's the characteristics of a speckle. Okay, so now I just would like to say a couple of words because I have shown you many examples of that use actually this vectorial typography. So one question that may arise is when do I need to use vectorial? What are the conditions for which I need vectorial or can I remain scarred? So this is why I call this when does polarization matter. So if you want to find it to answer to this question, you have to know how does the investigated object affect the light polarization. So the question is not about the light you use, it's about how the lights polarization is affected. So that means that if you have an object, any object here that illuminate with a very specific light, which is here, for instance, an elliptical one. And that object generates, let's say an absorption, you see that the light is weaker here, also a phase shift. But if I keep here the same state of polarization, this light does not affect polarization. So that problem could remain treated as a scalar one. And so I can have this way of treating problems as a scalar for any polarization or even unpolarized light as long as the states of polarization remain the same where I measure. Okay, so but there are some situations also where polarization is affected. And here I'm just giving you some examples about resonant magnetic scattering because this is some calculation theoretical calculation that I've made a couple of years ago. And I think it could be interesting for some of the people in the audience here. So, don't ask me too much about magnetism because I'm not an expert but anyway I understood that's when you have in this situation you could describe your object by this kind of matrix here, we have some charge and magnetic scattering which plays at this position in a Jones matrix. So in this case, if you want, depending what you are interested in, if you are interested in the charge information, then of course here the answer is that you just have to target this term of the Jones matrix, meaning that you just have to use parallel polarization with a single measurement and you will get a map of the FC. If you are interested, on the other hand, on FMMZ, which is this one, then by observing this one tells you that you just need to use cross linear polarization and you will directly get this information here. Okay, but I mean this is very specific and for instance, if you want to use a circular polarization and no analysis and it has been made by this group here, you could very easily check that what you will be measure depending on the way you polarize if it is left or right, you will have this combination with a plus or a minus. And this is a way to actually measure properties of decrease of decrease of magnetic decrease and this has been made here in this way. Okay, so that show you that actually depending on what you are interested in. It is maybe not always necessary to go for Victorio. So depending what you want to have another example here which were recently in a literature where people were interested in linear decrease. So this is a case where you have an absorption that depends on the polarization. And here the approach was actually to use several angle of illumination, I mean angle of linear polarization illumination, so that was several scalar typography measurements and reconstructions. And so they could get different kind of images depending the way they actually illuminate their objects. So this is another way to use a kind of scalar typography even on materials that affects the polarization of it. Okay, so I'm done. Just to summarize this. So this is a computational phase retrieval imaging. What is important is what you image are Jones matrices. It offers a very reasonable resolution in terms of microscopy it's adapted to very large object. And it's suitable for precision dependent materials. And it has the advantage to provide a quantitative diagnosis for optical components, especially when they evolve phase and polarization together. So it could be a nice approach for reverse engineering of metasurfaces for instance. I've also shown you how to imagine a vectorial light field. A couple of words about my colleagues, I will especially thanks to Arthur Baroni because most of the things have presented here were done during his PhD. And now he's a postdoc at PSI. And to also my colleagues Mark Allen, Peng Lee, Peng is now at Diamonds, Julien Dubois and Virginie Shamar and King was song and patrician vein co worker at the crowd were the guy who actually made the metasurfaces and you for your attention. Thank you.


So for today, a couple of things on the agenda. One, we'll do an action item review to run through some of the topics from the last TSC call, which was about two weeks ago. From there, have a quick discussion around the Garrett migration. Just do a quick follow up there and then move on to the work group updates. Is there anything else that folks would like to see get added to the agenda for today? All right, sounds good. So I think the first thing we'll do is just move into a quick hack fest discussion starting with a readout from the San Francisco hack fest last week and then talk a little bit about the upcoming hack fest. So Brian or any of the other folks that were at the hack fest last week just want to give a quick update to the group on some of the progress and discussions there. Yeah, I think we ran a good two day session. I was really happy to see the level of attendance we had about north of 60 participants and people seemed to stay pretty much the whole time. In terms of agenda, we mixed it up quite a bit but I think try to make sure we had conversations about both fabric and thoughts as like as Bob was talking about the whole room at times about kind of where we take this project from a number of different angles, such as we had a security and risk conversation about what it, we kind of walked through the maturity of software PowerPoint deck example. We talked about demos for Steve-O's and kind of decided that we should probably just do canned videos rather than trying to do some sort of reliability. We talked about the future of fabric and kind of the path from here to fabric 1.0 and, you know, I'm sorry, I'm sorry, I'm sorry, I'm sorry. And the architecture working group that's just kind of quite a bit of a time kind of where we had as well. Finally, we had a couple of special guests from the crowd at the Continent Quickly. We had a conversation at the Identity Working Group talking about kind of the attribute system in the certificate authority and membership services system that we have in fabric. So all in all, I felt like there's a good mix of self-directed learning and collaboration along with a chance of a community to talk about some issues. Certainly some things we've learned about for the next time, I think, but all in all, I was pretty happy. I don't know if anyone else wanted to share thoughts or updates to help with others who weren't there would benefit from hearing. All right. You all can hear me, okay. Yep. All right, if no other updates, we can move forward into the upcoming hack fest at this point.  With an afternoon chat, if there was a written kind of conclusion of the event, we've not prepared one formally. A lot of the discussions there led to actions in the different working groups and lists, but there wasn't a formal written kind of summary. There was a page that had an agenda for the hack fest that we could share around. So if you could see what we talked about with you like this conversation, Todd would paste it there. Yeah. Okay. Consider now. So moving forward for the upcoming hack fest, there are two on the calendar. The next one will be August 24th and 25th. That'll be a virtual hack fest like we did in the month of June. So in the upcoming TSC meeting, we'll kick off an agenda doc for that so people can start pulling together various agenda items or topics that they'd like to discuss or accomplish in this. And then we'll get a kickoff scheduled in the morning as well as checkpoints in the evening like we did in the previous hack fest that seemed to work well. And then the work groups and other groups are able to meet in variety of ad hoc meetings throughout the day. Onward from there, the next hack fest is confirmed. It will be in Amsterdam. It will be October 3rd and 4th. ABN Amro will be hosting this in tandem with IBM Netherlands and Holland Fintech as well as the Hyperledger project. So we will get the microsite set up for that in the coming days and get a registration link out to everyone so they have all the details that they need and understand how to register for that. And we will also begin pulling together an agenda doc for that to start iterating on as it gets closer to the event. And again, this is right after the CyBus event in Geneva, so for those that don't live in Europe and are traveling, it should be relatively convenient to also be able to attend this. Any questions on any of the hack fest updates before we move forward? Not a question, just a comment for me that I think we know that the virtual hackathon, the virtual hack fest last time had some limited participation. Yeah, I think there were a bunch of ideas that floated around for a better way to do it and I think they largely revolved around teeing up some specific action items or specific work items or goals for us for that let's you day stretch. Now that we have with Fabric an emerging sense of what's to end between us and really it may be very useful for us to think about what we could do by that point to have work items on that roadmap, you know, develop into issues in the issue tracker, develop into kind of bite-sized tasks that could be used to try to onboard some new developers or find developers who have now climbed a bit of a learning curve further beyond that and actually contribute it into the forward momentum. Just as a useful kind of motivating event I think with that way, so we can get the most out of those two days. Hey, all right, just listening to the hyperledger call there, talk about the cybos. Oh, if you're on mute. Okay, and then with that I think we can move into the maturity of software discussion picking up from two weeks ago. Jeremy or Bill, are the two of you on the line? Hi Todd, this is Jeremy Severide. Just a quick report back. So since we last spoke we presented the risk assessment worksheet-based approach to the requirements working group and got a favorable reception and got agreement to incorporate the approach into the use cases and use case template. And Bill and I as part of that walked through a spreadsheet that he and I are compiling of risks and mitigations database, a start of the database of sorts because these are often important for enterprise development where you need to be able to show you thought through some of the risks and mitigations associated with the deployment. And we also incorporated into that a part of a discussion from the identity work group session. There was a discussion there where they were talking about how to prioritize the feature development for membership services. And as part of that discussion, a bucketing of features for a prioritization came out and so we've begun to incorporate that. And so as next steps we will start to develop that database some more as well as start to update the use case template as well as a couple of the use cases to incorporate the risk assessment methodology that we discussed. Any questions? Yeah, I just want to say we did talk about the deck at the hackathon and many people found it useful as a way to start to walk through what we may want to be thinking about when we go to a one dot early and so I just wanted to thank you for that work. Oh, you're welcome. That's good to hear. We'd be happy to follow up with folks offline if they'd like to talk more as well. Great, thanks. All right, honored from there, Brian. I think picking up the release taxonomy discussion is next on the agenda. Yeah, and I had committed to, I did not, I do what I committed to last week, I apologize, which was integrate December versioning number entered into the release taxonomy. So I want to come back to that next week, but just as an update for folks who are looking at this, we'll try to blend the two of these so that the versioning number format proposed by Tim is we'll work into our alpha data production. So still looking for input on that and comments on the Google Docs, but there's one more iteration for me to do and then hopefully next week we could approve it and watch it. Great, thanks. All right, the next topic is the upcoming TSC election as we move into steady state. We've talked about this the last couple of weeks. Just as a reminder, we will open the nomination phase for that election next Thursday, August 11th. And I'm going to paste into the chat window right now. This is a list of all the contributors. We are currently going through and cleaning up this list and adding names to the emails or emails to names that we had. It's a bit of a manual process. So please first go in and check, make sure your name is on the list if it should be on the list. If it's not on the list, please shoot me an email. And then the second thing is if you see your name in there and it doesn't have the email or your email doesn't have the name, feel free to help us out and just add a comment into the doc with either of the missing information. We'll get that put in there. Any questions on the upcoming election? All right, sounds good. And the last thing from the action item review, a couple of weeks back there was an initial proposal on the Explorer. And I think Chris was working with DTCC on bringing that back to the group for review. I know Chris is out this week, not sure if anyone from DTCC is on that wants to speak to that or if we... Go ahead. Todd, so I made some updates. I'll first go back with Dan and Chris again and we'll bring basically and post this document on the weekly, the updated document. And I think we can discuss this in the next DST meeting. All right, thanks, Bart. That sounds good. Okay. All right, that completes the action item review from the last DST meeting. So the next agenda item... Well, one thing I'm sorry, just added on the Explorer proposal is that one of the things that was done at the hack fat last week was that Chris and Dan from Intel, just for the sake of everyone else on the call, Chris and Dan from Intel, and sorry, Bart, just from DTCC. Three of them sat together and came up with a, at least a path forward for a unified proposal for building on top of this initial contribution with code and common interfaces from both IBM and Intel to be able to talk to both fabric and software. So it seemed like a good thing and too much momentum towards the converge picture for the score as we talked about the past. So I think just because Chris was on vacation this week, we haven't perhaps been more, there will be more to talk about hopefully next week. Sounds good. All right, the next agenda item, there was some discussion on follow-up from the Garrett migration that got pushed to the TSC channel. So just wanted to bring that up on this call. And Brian, do you want to have that discussion? Yeah, there are a couple of outstanding migration questions that follow on from this move. And also, I just wanted to open up for anybody who wanted to be able to kind of express the point of view or note other remaining things to kind of close on this. But with this move, because we moved where the repository is, the core upstream repository, no longer is on GitHub, it's on garret.hyperlitter.org, it has a couple of other ramifications. And so one of those was a conversation that was posted to the TSC list initially in the fabric, and kind of also in the fabric list, which is a discussion as to whether we want to, where we want the Go tools to be able to pull the, basically pull from, which mirror do they want to pull from? They want to use when they're pulling code into the build environment. There was a proposal with two different options. I'm referring here to an email from Chris on July 30th this past Saturday. There's an option one, which was to mirror the fabric repo with the GitHub, which we will do anyways for the sake of making sure that commits from individuals not actually contribute to their GitHub profile to have a present on GitHub as a downstream mirror, but to have the Go tools actually map to that and pull down resources from that. Or do we, the option two, establish a non-Github identity within the Go tools and actually pull directly from garret.hyperlitter.org. And I think we can evolve that over time. We could even just continue to sort that out over the mailing list. It didn't seem like there was a clear overwhelming consensus for one versus two. So maybe we should just continue to work that out on the list, but if people felt like there was a, they had a strong sentiment one way or the other, might be worth talking about that in a call. So any comments on that? So if you're looking forward to hear email clients, it's dealing with the Go import path post-garrot migration. If there aren't any comments, we could just continue to iterate on the list as we follow the race path. There's another issue having to do with the read the docs build process, as noted by Josh Hornton in an issue. So it hasn't quite come up yet to the public list. We'll need to redo how we rebuild, read the docs up directly from Garrett. And we can look at what that takes from the Phoenix Foundation's side. And this is something that's easy for us to manage. So we'll go ahead and do that. If not, we may want to work with the volunteers to get that set up. Or wait until we do this kind of flip around where GitHub is mirroring from Garrett. And then we can have read the docs build, continue to build from GitHub. One way or the other, we won't leave read the docs behind. Are there any other comments that people have had? I mean, the last thing that I will say, which echoes what I said on the list is there's probably more that we could have done on our side. And I say we collectively, mostly the Phoenix Foundation, but also some of the others that have worked on this issue to kind of prepare the development community for what that migration means. I think we wanted to take the opportunity of Rai and Chris being in the same room at the same time during the hack test to make this happen, to follow up on a decision made even before I joined to move to Garrett. It's just probably something we could have communicated more clearly and helped people through things like having to do a fresh checkout, rebate their pull requests, that sort of thing. So I'll be a bit of a man cultist, but I think we're past the worst of that now. And on a really good platform for being able to move even more quickly through a world where we're ingesting contributions from a lot of different places. Any other concerns or thoughts about the move from GitHub to Garrett? So this is Arnaud. I just wanted to point out, I mean, you just talked about pull requests, and I think the big change, you know, for people who are not familiar with Garrett is the big change is you don't do pull requests anymore. And so you don't work off a fork. You work off the clone of the repository directly. And the basic workflow is that when you do a push, it's really going to create some kind of pull request, which in this case is submission for code review. I've actually gone through this now once to do an exercise. And I mean, it does take a little bit of getting used to, but the code review is definitely useful. And as Chris was updating all the documentation to give the information how to work with fabric, using Garrett as opposed to GitHub, we had to do a lot of documentation updates, and Chris did most of it. But several of us participated in the code review, and it's clear that we were able to catch a lot of errors and stuff that before it would have been harder to do. And so there's definitely value in this Garrett code review process. And it might be worth pointing out that Rai actually a few months ago recorded some kind of video. A video available for people to get an introduction to how we've been to Garrett functions. But so people should, you know, if you need help, please ask. There are pointers we can provide on how to get started. There are still some choices that need to be made as to how we use branches and things like that. It's, again, quite different from how it's typically done with GitHub. And as a group, we need to adopt some conventions. And I expect us to figure those out as we move forward. On the sawtooth side, first of all, I appreciated the on-the-fly presentation that Rai did at the Hackfest. I thought that was really informative. We've got a couple key people on our CI team that are on vacation, so we haven't been able to progress the conversation within the sawtooth team. But short of moving that further, our view is that we don't really have a broken process that we need to fix over on sawtooth, and it looks like there's going to be some not insignificant changes that would have to take place for Garrett. So we'll continue to look at that, but there's not any immediate changes on the sawtooth side. It is going to be... There is value in being able to have consistent processes across a project like Hyperledger. There's also value in making a switch like this earlier in the development of MyPipe over others. I think it's appropriate for authors to decide not to be the first to jump across this and to come along later and for us to see other ways to reduce the cost of such a migration or make it easier to follow. I think the TSC should talk about, should there be a single standard for how to do things across the project or is it fine for there to be parts of this project that live on GitHub or not? I'd like to be neutral on that issue, but I have a bias towards consistency across the project. So I'd love to just hear your thoughts on that and other thoughts on that. Yeah, I suppose that's kind of an awkward decision flow at this point since the Garrett decision was kind of, from my perspective, a feta-compley that came through. So we're going to continue to look at it, particularly once our guys get back from vacation. We'll be able to get a better understanding of what that would mean for us, but at the moment it looks like a tax with minimal benefit. But that's not to say that we're unwilling to continue to look at that. Happy to have it be an ongoing conversation. If anyone else wanted to express their thoughts now on that topic, it'd be fine, otherwise we'd just refer this to the future. There are a couple of more things that may be worth pointing out on the Garrett transition. So just to clarify, we will keep the GitHub repo that was existing for Fabric. It's redone-ly now and it's going to be synced with Garrett as we go forward. At the same time, Garrett does not contain all the different comets. There was some email exchange about this. Brian explained quite well the legal reasons as to why we had to squash all the comets as we transitioned to Garrett. But there is going to be also an archive copy of the GitHub repo at the time of the transition so that they will be both in GitHub, the current version, and the version as to the day we transitioned to Garrett available. And in terms of all the social aspect of GitHub that gives people's activity and all this stuff, all this should be reflected moving forward as if we had not transitioned as long as you use the same email address for your Linux foundation ID and your GitHub ID. Exactly. Okay, any other comments overall on the Garrett migration? Okay. All right, sounds good. Finally, we'll move into the workgroup updates. Starting with the requirements workgroup is Oleg on the line. All right, we'll look for an email update from Oleg. Ram in the architecture working group. Hi, yes. So we had a very good couple of sessions at the face to face in San Francisco with the significant turnout. So the first session was on documenting the first workgroup item around the consensus layer as well as the smart contract layer and the interface between them. We've made significant progress that we didn't quite get to the full outline that we wanted to. And so as part of the ongoing work, we're going to have a separate track to focus on and complete the documentation of the first topic. And we've decided on our regular meetings that we will continue. So that's the focus of the second session that we had in the face to face. And we're going to continue on with it in our regular meetings and on email hopefully. That is the focus on security and privacy requirements and the security functions. The main topic that came up in the face to face was bootstrap requirements and identity around that. So for those interested, please join the architecture workgroup mailer and our calls on Wednesday. Any questions? Thanks. All right. Thanks, Ram. All right. Moving forward to Dave and the white paperwork group. Hi, yes. So we met again yesterday and we reviewed some of the final updates that we wanted to get out there for our next publication and we were able to complete that. So I'm happy to report. If you look on the Wiki, if you go to the white paper working group Wiki page, you'll see that we have now published draft version 2.0. So the last draft we published was I think June 20 something towards the end of June. So quite a bit of edits in there. We believe that we've addressed all of the comments and feedback that we've received in this version. So if you've been kind of holding off waiting to see the next version before you take another read and submit new feedback, well, now it's there. So we haven't had any new feedback in about three weeks. So I'm hoping now that we've got this new version out there that we'll get more people reviewing it and to give us some feedback. Hi, David. Can you post a link? Probably best on the mailing list and then it appears as an inbox item. But I must admit, I miss that there's a new thing to review. If you post a link, then I'll add it to me to do this to look at it. Sure. I will post that into the chat room here. Okay. And also I think that they're typically those links are typically included in the minutes that Todd sends out after our meetings as well. But I'll go ahead and do that right now. Thanks. I missed it. Sure. No problem. Great. Thanks, Dave. Any other questions or comments for Dave? All right. Thanks Dave. Is Christopher Allen on to do update from the identity work group? I think we'll look for that via email as well. In terms of the CI work group, I know Chris Ferris is out. Brian, I don't know if there's anything you wanted to add related to that on the fly. If not, we'll look for that from Chris next week. No, I don't. Okay. All right. And that brings us to the end of a relatively short agenda for today. Are there any other topics that people would like to discuss at this point? Otherwise, we're happy to give folks some time back today. No further agenda items. So with that, thank you everyone for your time. And happy to give you about an hour back for the day. We'll get some minutes out shortly here. Thanks, everyone. Thanks, guys. Thanks. Bye. Bye. Thank you.