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LeopoldS

how to use the results our Diigo bookmarks for the benefit of rest of ESA - 11 views

just listening to a company representative - funnily called Michael Jackson - who presents their tool called "shaping tomorrow" who do exactly the same as we do with Diigo but on a commercial basis...

started by LeopoldS on 24 Jun 09 no follow-up yet
LeopoldS

Cold storage - an Arctic solution to the data storage cooling problem | In-depth | The ... - 0 views

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    from Andrés (don't ask my why he is not putting it directly on diigo ....) quite an old issue, though still of high actuality ... and a nice summary in my view ...
Dario Izzo

Optimal Control Probem in the CR3BP solved!!! - 7 views

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    This guy solved a problem many people are trying to solve!!! The optimal control problem for the three body problem (restricted, circular) can be solved using continuation of the secondary gravity parameter and some clever adaptation of the boundary conditions!! His presentation was an eye opener ... making the work of many pretty useless now :)
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    Riemann hypothesis should be next... Which paper on the linked website is this exactly?
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    hmmm, last year at the AIAA conference in Toronto I presented a continuation approach to design a DRO (three-body problem). Nothing new here unfortunately. I know the work of Caillau, although interesting what is presented was solved 10 years ago by others. The interest of his work is not in the applications (CR3BP), but in the research of particular regularity conditions that unfortunately make the problem limited practically. Look also at the work of Mingotti, Russel, Topputo and other for the (C)RTBP. Smart-One inspired a bunch of researchers :)
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    Topputo and some of the others 'inspired' researchers you mention are actually here at the conference and they are all quite depressed :) Caillau really solves the problem: as a one single phase transfer, no tricks, no misconvergence, in general and using none of the usual cheats. What was produced so far by other were only local solutions valid for the particular case considered. In any case I will give him your paper, so that he knows he is working on already solved stuff :)
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    Answer to Marek: the paper you may look at is: Discrete and differential homotopy in circular restricted three-body control
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    Ah! with one single phase and a first order method then it is amazing (but it is still just the very particular CRTBP case). The trick is however the homotopy map he selected! Why this one? Any conjugate point? Did I misunderstood the title ? I solved in one phase with second order methods for the less restrictive problem RTBP or simply 3-body... but as a strict answer to your title the problem has been solved before. Nota: In "Russell, R. P., "Primer Vector Theory Applied to Global Low-Thrust Trade Studies," JGCD, Vol. 30, No. 2", he does solve the RTBP with a first order method in one phase.
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    I think what is interesting is not what he solved, but how he solved the problem. But, are means more important than end ... I dunno
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    I also loved his method, and it looked to me that is far more general than the CRTBP. As for the title of this post, OK maybe it is an exageration as it suggests that no solution was ever given before, on the other end, as Marek would say "come on guys!!!!!"
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    The generality has to be checked. Don't you think his choice of mapping is too specific? he doesn't really demonstrate it works better than other. In addition, the minimum time choice make the problem very regular (i guess you've experienced that solving min time is much easier than mass max, optimality-wise). There is still a long way before maximum mass+RTBP, Topputo et al should be re-assured :p Did you give him my paper, he may find it interesting since I mention the homotopy on mu but for max mass:)
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    Joris, that is the point I was excited abut, at the conference HE DID present solutions to the maximum mass problem!! One phase, from LEO to an orbit around the moon .. amazing :) You will find his presentation on line.... (according to the organizers) I gave him the reference to you paper anyway, but no pdf though as you did not upload it on our web pages and I could not find it in the web. So I gave him some bibliography I had with be from the russians, and from Russell, Petropoulos and Howell, As far as I know these are the only ones that can hope to compete with this guy!!
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    for info only, my phd, in one phase: http://pdf.aiaa.org/preview/CDReadyMAST08_1856/PV2008_7363.pdf I prefered Mars than the dead rock Moon though!
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    If you send me the pdf I can give it to the guy .. the link you gave contains only the first page ... (I have no access till monday to the AIAA thingy)
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    this is why I like this Diigo thingy so much more than delicious ...
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    What do you mean by this comment, Leopold? ;-) Jokes apart: I am following the Diigo thingy with Google Reader (rss). Obviously, I am getting the new postings. But if someone later on adds a comment to a post, then I can miss it, because the rss doesn't get updated. Not that it's a big problem, but do you guys have a better solution for this? How are you following these comments? (I know that if you have commented an entry, then you get the later updates in email.) (For example, in google reader I can see only the first 5 comments in this entry.)
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    I like when there are discussions evolving around entries
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    and on your problem with the RSS Tamas: its the same for me, you get the comments only for entries that you have posted or that you have commented on ...
duncan barker

YouTube - BigDog Overview (Updated March 2010) - 5 views

shared by duncan barker on 17 Nov 10 - No Cached
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    initially disgusting.........but amazing
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    this was probably already 5 times on our diigo group ... and before this a few times on the predecessor of diigo ...
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    Maybe it's a sign that every ACT member should ride one of these to get to work?
nikolas smyrlakis

Good-Bye Alta-Vista, Delicious | ZDNet - 2 views

shared by nikolas smyrlakis on 17 Dec 10 - No Cached
LeopoldS liked it
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    we were 1,5 year ahead to switch to diigo !
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    Man, I remember, long long time ago, altavista was my first contact with the internet ever.
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    indeed ... and it was largely thanks to you ... remember well the discussion in the group meeting with the arguments brought forward: why change, it works ...
Tobias Seidl

WikiCFP : Call For Papers of Conferences, Workshops and Journals - 3 views

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    This is my first post to the ACT-Diigo in 18 months! Anyways a semantic wiki which collects calls for papers on all different fields - that should have been an ACT invention. SHAME ON YOU!!!
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    nice!
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    Come on guys, it's out there for centuries...
LeopoldS

Three-body Gallery - 2 views

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    loads of new solution classes to the three body problem found by Bulgarians ... Francesco and Sante, you will love these
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    ups, should have looked at diigo before ... Luis was faster again
LeopoldS

Drone 'space ship' app to help robots on future missions - 3 views

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    some of the quotes in there are a bit limit ... :-)
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    I would well imagine a team at an other space institution, with their own diigo, commenting on that news ... ;p Interesting trend nonetheless. At the NASA Space Apps Challenge, few teams proposed a similar G&C application but for the rover Curiosity... this is certainly a good approach for citizen science.
santecarloni

Physics World reveals its top 10 breakthroughs for 2011 - physicsworld.com - 4 views

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    hello, funny bug on diigo ! I shared this link on 16 Dec and Sante on 22 Dec, but my share disapeared...
Luke O'Connor

Movember! - 3 views

shared by Luke O'Connor on 10 Nov 11 - Cached
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    Movember (formerly November) is a moustache growing charity event during November. This month I am growing a moustache to raise awareness (and funds) for men's health. I will be putting a collection jar on my desk, so any donations of spare change would be very much appreciated! My 'mospace' can be found here: http://mobro.co/Lukeoc hijaking of diigo over...
johannessimon81

Bendable glass - 4 views

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    Corning unveiled a new flexible glass -- called "Willow Glass" -- at the Society for Information Display's Boston Display Week on Monday. It's about as thick and flexible as a piece of paper, while having the strength, durability and other qualities of existing glass.
Dario Izzo

ACT / ESA - News - Biologists find bees land like spacecraft - 2 views

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    The opposite of biomimetic :)
johannessimon81

RT @JustBe74: China Unveils Its First and Unnamed Moon Rover - 0 views

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    Found this on Twitter ;-) This is also a test to see if Diigo titles get processed correctly as re-tweets...
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    Yes. Worked.
Dario Izzo

The Micro: The First Truly Consumer 3D Printer by M3D LLC - Kickstarter - 4 views

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    We must get one of these. They had a goal of 50.000$ but got, instead more than 3,000,000$ !!
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    Really bad market analysis on their part...
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    https://www.kickstarter.com/projects/formlabs/form-1-an-affordable-professional-3d-printer?ref=live i think this is the one I was talking about the other day. ~3M$ from 100k$ target in 2012. I think I remembered it though cos they got sued for patent infringement and it was the first time kickstarter had been included in the lawsuit. I may even have posted the story on diigo...
Francesco Biscani

The End Of Gravity As a Fundamental Force - 6 views

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    "At a symposium at the Dutch Spinoza-instituut on 8 December, 2009, string theorist Erik Verlinde introduced a theory that derives Newton's classical mechanics. In his theory, gravity exists because of a difference in concentration of information in the empty space between two masses and its surroundings. He does not consider gravity as fundamental, but as an emergent phenomenon that arises from a deeper microscropic reality. A relativistic extension of his argument leads directly to Einstein's equations."
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    Diffcult for me to fully understand / believe in the holographic principle at macroscopical scales ... potentially it looks though as a revolutionary idea.....
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    never heard about it... seems interesting. At first sight it seems that it is based on fundamental principle that could lead to a new phenomenology, so that could be tested. Perhaps Luzi knows more about this ? Did we ever work on this concept ?
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    The paper is quite long and I don't have the time right now to read it in detail. Just a few comments: * We (ACT) definitely never did anything in this direction? But: is there a new phenomenology? I'm not sure, if the aim is just to get Einstein's theory as emergent theory, then GR should not change (or only change in extreme conditions.) * Emergent gravity is not new, also Erik admits that. The claim to have found a solution appears quite frequently, but most proposals actually are not emergent at all. At least, I have the impression that Erik is aware of the relevant steps to be performed. * It's very difficult to judge from a short glance at the paper, up to which point the claims are serious and where it just starts to be advertisments. Section 6 is pretty much a collection of self-praise. * Most importantly: I don't understand how exactly space and time should be emergent. I think it's not new to observe that space is related to special canonical variables in thermodynamics. If anybody can see anything "emergent" in the first paragraphs of section 3, then please explain me. For me, this is not emergent space, but space introduced with a "sledge hammer." Time anyway seems to be a precondition, else there is nothing like energy and nothing like dynamics. * Finally, holography appears to be a precondition, to my knowledge no proof exists that normal (non-supersymmetric, non-stringy, non-whatever) GR has a holographic dual.
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    Update: meanwhile I understood roughly what this should be about. It's well known that BH physics follow the laws of theormodynamics, suggesting the existence of underlying microstates. But if this is true, shouldn't the gravitational force then be emergent from these microstates in the same way as any theromdynamical effect is emergent from the behavior of its constituents (e.g. a gas)? If this can be prooven, then indeed gravity is emergent. Problem: one has to proof that *any* configuration in GR may be interpreted as thermodynamical, not just BHs. That's probably where holography comes into the play. To me this smells pretty much like N=4 SYM vs. QCD. The former is not QCD, but can be solved, so all stringy people study just that one and claim to learn something about QCD. Here, we look at holographic models, GR is not holographic, but who cares... Engineering problems...
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    is there any experimental or observational evidence that points to this "solution"?
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    Are you joking??? :D
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    I was a bit fast to say it could be tested... apparently we don't even know a theory that is holographic, perhaps a string theory (see http://arxiv.org/abs/hep-th/9409089v2). So very far from any test...
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    Luzi, I miss you!!!
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    Leo, do you mean you liked my comment on your question more than Pacome's? Well, the ACT has to evolve and fledge, so no bullshitting anymore, but serious and calculating answers... :-) Sorry Pacome, nothing against you!! I just LOVE this Diigo because it gives me the opportunity for a happy revival of my ACT mood.
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    haha, today would have been great to show your mood... we had a talk on the connection between mind and matter !!
pacome delva

Physicists study how moral behaviour evolved - 2 views

  • A statistical-physics-based model may shed light on the age-old question "how can morality take root in a world where everyone is out for themselves?" Computer simulations by an international team of scientists suggest that the answer lies in how people interact with their closest neighbours rather than with the population as a whole.
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    Reminds me something... :)
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    I check diigo for the first time since I left and my spirit is still there yeah !
Luzi Bergamin

Prof. Markrams Hirnmaschine (Startseite, NZZ Online) - 2 views

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    A critical view on Prof. Markram's Blue Brain project (in German).
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    A critical view on Prof. Markram's Blue Brain project (in German).
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    so critical that the comment needed to be posted twice :-) ?
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    Yes, I know; I still don't know how to deal with this f.... Diigo Toolbar! Shame on me!!!
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    Would be nice to read something about the modelling, but it appears that there is nothing published in detail. Following the article, the main approach is to model each(!) neuron taking into account the spatial structure of the neurons positions. Once achieved they expect intelligent behaviour. And they need a (type of) supercomputer which does not exist yet.
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    As far as I know it's sort of like "Let's construct an enormous dynamical system and see what happens"... i.e. a waste of taxpayer's money... Able to heal Alzheimer... Yeah... Actually I was on the conference the author is mentioning (FET 2011) and I have seen the presentations of all 6 flagship proposals. Following that I had a discussion with one of my colleagues about the existence of limits of the amount of bullshit politicians are willing to buy from scientists. Will there be a point at which politicians, despite their total ignorance, will realise that scientists simply don't deliver anything they promise? How long will we (scientists) be stuck in the viscous circle of have-to-promise-more-than-predecessors in order to get money? Will we face a situation when we'll be forced to revert to promises which are realistic? To be honest none of the 6 presentations convinced me of their scientific merit (apart from the one on graphene where I have absolutely no expertise to tell). Apparently a huge amount of money is about to be wasted.
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    It's not just "Let's construct an enormous dynamical system and see what happens", it's worse! Also the simulation of the cosmological evolution is/was a little bit of this type, still the results are very interesting and useful. Why? Neither the whole cosmos nor the human brain at the level of single neurons can be modelled on a computer, that would last aeons on a "yet-to-be-invented-extra-super-computer". Thus one has to make assumptions and simplifications. In cosmology we have working theories of gravitation, thermodynamics, electrodynamics etc. at hand; starting from these theories we can make reasonable assumptions and (more or less) justified simplifications. The result is valuable since it provides insight into a complex system under given, explicit and understood assumptions. Nothing similar seems to exist in neuroscience. There is no theory of the human brain and apparently nobody has the slightest idea which simplifications can be made without harm. Of course, Mr. Markram remains completely unaffected of ''details'' like this. Finally, Marek, money is not wasted, we ''build networks of excellence'' and ''select the brightest of the brightest'' to make them study and work at our ''elite institutions'' :-). I lively remember the stage of one of these "bestofthebest" from Ivy League at the ACT...
Christos Ampatzis

Elucidating the cooperative behaviour of sensory nerves - 1 views

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    From research*eu magazine
Christos Ampatzis

What it takes to be a team player - 2 views

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    PD's article presented to the idea storm: "They find the data can best be explained using a model that says an individual can join a team if she/he can bring some new, complementary skills to the group. This interpretation goes against the idea that an individual will tend to mainly join-and remain comfortable in-groups of "like-minded" people."
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    nice article according to the abstract but can't download the paper (can we from within ESA? do you have it already downloaded - would be interested in reading the full paper - can we apply this to behaviour and size of the ACT?
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    Yes it is available within ESA's network - I have it anyway
nikolas smyrlakis

BBC NEWS | Technology | 'Road trains' get ready to roll - 3 views

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    sleeping and driving on the highway
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    "The lead vehicle would be handled by a professional driver who would monitor the status of the road train. Those in following vehicles could take their hands off the wheel, read a book or watch TV, while they travel along the motorway. Their vehicle would be controlled by the lead vehicle." .... what or who is defining a professional driver? one of the always overly tired truck drivers?
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