Skip to main content

Home/ Advanced Concepts Team/ Group items tagged stuff

Rss Feed Group items tagged

Thijs Versloot

Shapeshift electroactive polymers - 3 views

  •  
    Not very new, but interesting stuff, maybe related to space suits or unfolding techniques of solar panels (which unfold as they are irradiated?)
Thijs Versloot

The entropy of encryption and how secure is it? - 1 views

  •  
    I like the following text: "It's still exponentially hard, but it's exponentially easier than we thought," Duffy says. One implication is that an attacker who simply relied on the frequencies with which letters occur in English words could probably guess a user-selected password much more quickly than was previously thought. "Attackers often use graphics processors to distribute the problem," Duffy says. "You'd be surprised at how quickly you can guess stuff."
LeopoldS

Space News - September 9, 2013 - 4 views

  •  
    why are we not getting these type of startups in Europe .... btw: Will is british
  • ...1 more comment...
  •  
    Nobody in Europe would invest 13Mio $ (or the equivalent in €) venture capital for this idea, it's just a different mentality. In Europe, VCs start to get interested when the investment risk is significantly lower.
  •  
    I agree, the mentality is different, it's hard to find VC funding for hardware stuff, even more so if you wanna shoot your HW into space. but there is movement, e.g. pioneers.io, they are in vienna and are actively trying to get more VC funding (in europe) for HW and other engineering startups
  •  
    thanks for the link ... just read this blog ... http://pioneers.io/blog/space-race-2-0-putting-satellites-into-the-hands-of-everyone a lot of selling talk but fundamentally I agree that they have a point ... and as ACT we will face the criticism in not so long that we have not managed (nor tried hard enough) to convince ESA about the need to embrace this "new space"
Athanasia Nikolaou

Nature Paper: Rivers and streams release more CO2 than previously believed - 6 views

  •  
    Another underestimated source of CO2, are turbulent waters. "The stronger the turbulences at the water's surface, the more CO2 is released into the atmosphere. The combination of maps and data revealed that, while the CO2 emissions from lakes and reservoirs are lower than assumed, those from rivers and streams are three times as high as previously believed." Alltogether the emitted CO2 equates to roughly one-fifth of the emissions caused by humans. Yet more stuff to model...
  • ...10 more comments...
  •  
    This could also be a mechanism to counter human CO2 emission ... the more we emit, the less turbulent rivers and stream, the less CO2 is emitted there ... makes sense?
  •  
    I guess there is a natural equilibrium there. Once the climate warms up enough for all rivers and streams to evaporate they will not contribute CO2 anymore - which stops their contribution to global warming. So the problem is also the solution (as always).
  •  
    "The source of inland water CO2 is still not known with certainty and new studies are needed to research the mechanisms controlling CO2 evasion globally." It is another source of CO2 this one, and the turbulence in the rivers is independent of our emissions in CO2 and just facilitates the process of releasing CO2 waters. Dario, if I understood correct you have in mind a finite quantity of CO2 that the atmosphere can accomodate, and to my knowledge this does not happen, so I cannot find a relevant feedback there. Johannes, H2O is a powerful greenhouse gas :-)
  •  
    Nasia I think you did not get my point (a joke, really, that Johannes continued) .... by emitting more CO2 we warm up the planet thus drying up rivers and lakes which will, in turn emit less CO2 :) No finite quantity of CO2 in the atmosphere is needed to close this loop ... ... as for the H2O it could just go into non turbulent waters rather than staying into the atmosphere ...
  •  
    Really awkward joke explanation: I got the joke of Johannes, but maybe you did not get mine: by warming up the planet to get rid of the rivers and their problems, the water of the rivers will be accomodated in the atmosphere, therefore, the greenhouse gas of water.
  •  
    from my previous post: "... as for the H2O it could just go into non turbulent waters rather than staying into the atmosphere ..."
  •  
    I guess the emphasis is on "could"... ;-) Also, everybody knows that rain is cold - so more water in the atmosphere makes the climate colder.
  •  
    do you have the nature paper also? looks like very nice, meticulous typically german research lasting over 10 years with painstakingly many researchers from all over the world involved .... and while important the total is still only 20% of human emissions ... so a variation in it does not seem to change the overall picture
  •  
    here is the nature paper : http://www.nature.com/nature/journal/v503/n7476/full/nature12760.html I appreciate Johannes' and Dario's jokes, since climate is the common ground that all of us can have an opinion, taking honours from experiencing weather. But, the same as if I am trying to make jokes for material science, or A.I. I take a high risk of failing(!) :-S Water is a greenhouse gas, rain rather releases latent heat to the environment in order to be formed, Johannes, nice trolling effort ;-) Between this and the next jokes to come, I would stop to take a look here, provided you have 10 minutes: how/where rain forms http://www.scribd.com/doc/58033704/Tephigrams-for-Dummies
  •  
    omg
  •  
    Nasia, I thought about your statement carefully - and I cannot agree with you. Water is not a greenhouse gas. It is instead a liquid. Also, I can't believe you keep feeding the troll! :-P But on a more topical note: I think it is an over-simplification to call water a greenhouse gas - water is one of the most important mechanisms in the way Earth handles heat input from the sun. The latent heat that you mention actually cools Earth: solar energy that would otherwise heat Earth's surface is ABSORBED as latent heat by water which consequently evaporates - the same water condenses into rain drops at high altitudes and releases this stored heat. In effect the water cycle is a mechanism of heat transport from low altitude to high altitude where the chance of infrared radiation escaping into space is much higher due to the much thinner layer of atmosphere above (including the smaller abundance of greenhouse gasses). Also, as I know you are well aware, the cloud cover that results from water condensation in the troposphere dramatically increases albedo which has a cooling effect on climate. Furthermore the heat capacity of wet air ("humid heat") is much larger than that of dry air - so any advective heat transfer due to air currents is more efficient in wet air - transporting heat from warm areas to a natural heat sink e.g. polar regions. Of course there are also climate heating effects of water like the absorption of IR radiation. But I stand by my statement (as defended in the above) that rain cools the atmosphere. Oh and also some nice reading material on the complexities related to climate feedback due to sea surface temperature: http://journals.ametsoc.org/doi/abs/10.1175/1520-0442(1993)006%3C2049%3ALSEOTR%3E2.0.CO%3B2
  •  
    I enjoy trolling conversations when there is a gain for both sides at the end :-) . I had to check upon some of the facts in order to explain my self properly. The IPCC report states the greenhouse gases here, and water vapour is included: http://www.ipcc.ch/publications_and_data/ar4/wg1/en/faq-2-1.html Honestly, I read only the abstract of the article you posted, which is a very interesting hypothesis on the mechanism of regulating sea surface temperature, but it is very localized to the tropics (vivid convection, storms) a region of which I have very little expertise, and is difficult to study because it has non-hydrostatic dynamics. The only thing I can comment there is that the authors define constant relative humidity for the bottom layer, supplied by the oceanic surface, which limits the implementation of the concept on other earth regions. Also, we may confuse during the conversation the greenhouse gas with the Radiative Forcing of each greenhouse gas: I see your point of the latent heat trapped in the water vapour, and I agree, but the effect of the water is that it traps even as latent heat an amount of LR that would otherwise escape back to space. That is the greenhouse gas identity and an image to see the absorption bands in the atmosphere and how important the water is, without vain authority-based arguments that miss the explanation in the end: http://www.google.nl/imgres?imgurl=http://www.solarchords.com/uploaded/82/87-33833-450015_44absorbspec.gif&imgrefurl=http://www.solarchords.com/agw-science/4/greenhouse--1-radiation/33784/&h=468&w=458&sz=28&tbnid=x2NtfKh5OPM7lM:&tbnh=98&tbnw=96&zoom=1&usg=__KldteWbV19nVPbbsC4jsOgzCK6E=&docid=cMRZ9f22jbtYPM&sa=X&ei=SwynUq2TMqiS0QXVq4C4Aw&ved=0CDkQ9QEwAw
johannessimon81

Water found on exoplanets - 1 views

  •  
    A few years ago we did not even know if there was any planets outside the solar system. Now we know some of the stuff that happens on them. Wonder how long it takes until we discover life somewhere else!
  •  
    I do not know what is yetto come, but I am looking forward to the "starshade" Sara Seager's team wants to couple to a telescope: "The star shade and the telescope have to be aligned perfectly at 125,000 miles away. Once aligned, the system will observe a distant star, and then move to another distant star and re-align. This is technologically speaking, unchartered territory." http://www.youtube.com/watch?feature=player_embedded&v=G68sqgRhP2E
Daniel Hennes

Bitcoins in Space - 0 views

  •  
    Jeff Garzik wants to make satellites part of the Bitcoin network to help secure the currency against attacks.
  •  
    remember the discussion we had about space being used as a safe network for this type of stuff ....?
Thijs Versloot

Does your iPhone have free will? #arXiv - 3 views

  •  
    If you've ever found your iPhone taking control of your life, there may be a good reason. It may think it has free will. That may not be quite as far-fetched as it sounds. Today, one leading scientist outlines a 'Turing Test' for free will and says that while simple devices such as thermostats cannot pass, more complex ones like iPhones might.
  • ...3 more comments...
  •  
    An interesting paper about how you should *NOT* think about free will...
  •  
    I must say that the fact that the outcome of a thought process is not evident to myself in advance sounds like a more plausible explanation than 'free will' being the product of quantum mechanics. The later would not only produce unpredictable decisions but probably also irrational ones...
  •  
    Even if it were the product of quantum mechanics, it's still the result of external interference and not the result of 'free' will. It doesn't matter if the external input is deterministic or random, it's still external and it's not "YOU" that decided stuff.
  •  
    I don't know the inventor of that nonsense that the free will should be the result of QM. It's about the only point I agree with the author of the paper: QM is not necessary and doesn't help. What I meant: all these thought experiments done by typical ultra-naive realists (or ultra-naive physicalists, if you prefer) that cultivate the university departments of physics, computer science etc. are put the cart before the horse. First one has to clarify the role of physical theories and its concepts (e.g. causality) and then one can start to ask how "free will" could perhaps be seen in these theories. More than 200 years ago there existed a famous philosopher named Kant who had some interesting thoughts about this. But authors like Lloyd behave as if he never existed, in fact is view of the world is even pre-Platonic!
  •  
    Henry Kissinger How I'm missing yer And wishing you were here
johannessimon81

Bill Nye - The Science Guy on Jupiter and the Juno spacecraft - 0 views

  •  
    Great explanations of space stuff for people who are not experts (for example children) :-)
johannessimon81

The Universe Is Programmable. We Need an API for Everything - 3 views

  •  
    Interesting ideas - though some metaphors are a bit far fetched. Personally, I think it could be interesting if every scientific article would also have a how-to or tutorial section that gives a recipe of how to apply the newly gained knowledge. Of course, that might be tough to do... :-)
  •  
    The API of the world is already there (a bit), it is the previous knowledge developed by others. Open Source projects such as the wheel or the brick, allow everyday amazing new APPs to be build such as buildings and cars .... There still is merit, though, in learning from software developments techniques in the everyday world projects. This is indeed the motivation for the ACT to do work in open source (SOCIS, GSoC) and push its members to use stuff like wiki, svn, github, jenkins, and alike. This way we are performing and fostering (http://www.oxforddictionaries.com/definition/english/foster) research into working methods in the hope we will be able to export some of its benefit to the larger ESA.
Thijs Versloot

Dutch company without any managers is inspiring industry (in dutch) - 0 views

  •  
    This dutch company, Schuberg, has no managers but instead all the employees (operating in the IT service industry) manage everything themselves. They offer IT support to KLM, Rabobank and Eneco, who are quite very reliant on the uptime of their systems. These companies rate Schuberg consistently with the highest approval. Harvard business school is now teaching this type of organizational structure. Possible new working method?
  •  
    just like the ACT :-)
Annalisa Riccardi

Dynamic Vision Sensors - 5 views

  •  
    New vision sensor from a swiss company seems to go beyond Elementary Motion Detectors (those inspired by insect vision)
  •  
    Nice stuff!
LeopoldS

Testla energy Tesla Motors - 2 views

  •  
    tesla announcing home batteries at 350$/kW
  • ...1 more comment...
  •  
    Good stuff, no way it will be done in the netherlands however due to the 'equal-return' law in place here still that puts the price of returning to the grid equal to the costs of buying. The costs of this law are enormous however and energy companies would love to get rid off it, and it will in the upcoming years most likely. I wonder however if that makes sense on a regional/national level, returning to the grid on that scale produces a more stable supply. Why store for personal use only?
  •  
    Let's do some simple maths... Here in UK, example "economy 7" tarif yields night kWh approx. 12 pence cheaper than during day. Let's say the goal is to store energy equivalent to running a 2kW storage heater for 6 hours during the day. We need 12 kWh, so 12 times $350 this means need to spend approx. 1920 pounds for batteries. Time to break even at ROI: 1920 / 0.12 ~ 7.3 years... And this is assuming using the heater 365 days a year, and quite an expensive tariff (prepaid). SIWB :-)
  •  
    Also need to take into account that battery capacity tends to go down with time and usage
johannessimon81

Update on Mars One - 2 views

  •  
    165000 people have applied and the founders of Mars One still seem enthusiastic. Wouldn't it be great if they actually could pull it off..?
Dario Izzo

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

  •  
    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 :)
  • ...13 more comments...
  •  
    Riemann hypothesis should be next... Which paper on the linked website is this exactly?
  •  
    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 :)
  •  
    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 :)
  •  
    Answer to Marek: the paper you may look at is: Discrete and differential homotopy in circular restricted three-body control
  •  
    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.
  •  
    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
  •  
    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!!!!!"
  •  
    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:)
  •  
    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!!
  •  
    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!
  •  
    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)
  •  
    this is why I like this Diigo thingy so much more than delicious ...
  •  
    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.)
  •  
    I like when there are discussions evolving around entries
  •  
    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 ...
Alexander Wittig

Neuronal Networks: Computers paint like van Gogh - 1 views

  •  
    A neuronal network trained to paint the scene of a given photograph in the style of Kandinsky, van Gogh, or Munch. Their results look quite impressive. Unfortunately the article is in German, but the English paper (with plenty of pictures) is here: http://arxiv.org/pdf/1508.06576v2.pdf Malen wie Kandinsky, wie van Gogh, wie Munch nur auf Basis einer Fotovorlage? Natürlich gibt es begabte Kunstfälscher, die das können. Jetzt aber gelingt es auch Computern, und zwar auf höchst eindrucksvolle Weise. Drei Forscher von der Universität Tübingen haben es geschafft, einem sogenannten künstlichen neuronalen Netzwerk das Malen beizubringen.
  •  
    Impressive stuff indeed. Paper came out one week ago. Multiple independent implementations have popped out since then: * https://github.com/Lasagne/Recipes/blob/master/examples/styletransfer/Art%20Style%20Transfer.ipynb * https://github.com/jcjohnson/neural-style * https://github.com/kaishengtai/neuralart
jcunha

Explosion-Generated Collapsing Vacuum Bubbles Reach 20,000 Kelvin - 1 views

  •  
    "In a recent paper published in Physical Review Letters (PRL) Jérôme Duplat and Emmanuel Villermaux developed a method to generate centimeter-sized vacuum bubbles in water with miniature laser-driven explosions, and observed the flash of light produced as the bubble collapsed a not-fully-understood phenomenon known as sonoluminescence." Amazingly they concluded that the temperatrue inside the bubble as it collapses is about 26000 K. At this temperatures some (not me) argue for nuclear fusion... Intriguing stuff!!! Check the videos! Yet another test for the 'Experimental Physics Stagiare' :-)?
  •  
    For sure no fusion, that starts appr. from about 20keV, not 20kK. Between both there is still a factor of 11500. What I would rather expect is that the conditions are not appropriate to work with Maxwellian distribution functions. If certain fusion products should be measurable, than this would rather confirm (but not proof) the hypothesis that they do not have Maxwellians but something close to monoenergetic. But most probably they will not measure fusion products, hence no fusion, hence no confusion.
jcunha

Where Life Meets Light: Bio-Inspired Photonics - 0 views

  •  
    Octopus and optoelectronics camouflage, light bugs and LEDs, or spider webs and touch screens, ... a whole cool bunch of biomimetic stuff
  •  
    See also the referred work "Light-extraction enhancement for light-emitting diodes: a firefly-inspired structure refined by the genetic algorithm" - quite cool! https://pure.fundp.ac.be/portal/files/11946897/paper89.pdf
Thijs Versloot

Personal Thermal Management by Metallic Nanowire-Coated Textile - 2 views

  •  
    By wearing clothes that have been dip-coated in a silver nanowire (AgNW) solution that is highly radiation-insulating, a person may stay so warm in the winter that they can greatly reduce or even eliminate their need for heating their home. With as extra bonus: Besides providing high levels of passive insulation, AgNW-coated clothing can also provide Joule heating if connected to an electricity source, such as a battery. The researchers demonstrated that as little as 0.9 V can safely raise clothing temperature to 38 °C, which is 1 °C higher than the human body temperature of 37 °C. How about that for personal comfort during the cold winter months
  • ...1 more comment...
  •  
    These applications seem more and more promising. However I wonder about the toxicity aspects of wearing this stuff and apparently some research is starting to be developed to assess that, see http://www.particleandfibretoxicology.com/content/11/1/52 showing results of pulmonary toxicity of AgNW
  •  
    sounds almost like the asbestos story re-started :-)
  •  
    Found an European project that takes care of the environmental, health and safety aspects of nanomaterials http://phys.org/news/2015-04-unleash-full-potential-nanomaterials.html
pacome delva

Nanofibres power portable electronics - 1 views

  •  
    cool, is there somebody coming to work on materials? and stuff like that?
« First ‹ Previous 41 - 60 of 97 Next › Last »
Showing 20 items per page