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Joris _

10 Business Models That Rocked 2010 - 11 views

techcrunch.com/...siness-models-that-rocked-2010

business web technology

shared by Joris _ on 09 Jan 11 - No Cached
  • Joris _ on 09 Jan 11
     
    What did work in 2010. The Quirky model might be of interest to ACT...
  • Luís F. Simões on 09 Jan 11
     
    Some great ideas in there. I particularly like the Flattr micropayments system, and find the concept of PayWithaTweet a bit disturbing.
jmlloren

Exotic matter : Insight : Nature - 5 views

www.nature.com/...index.html

nan phy

shared by jmlloren on 03 Aug 10 - Cached
LeopoldS liked it
  • jmlloren on 03 Aug 10
     
    Trends in materials and condensed matter. Check out the topological insulators. amazing field.
  • ...12 more comments...
  • Luzi Bergamin on 03 Aug 10
     
    Aparently very interesting, will it survive the short hype? Relevant work describing mirror charges of topological insulators and the classical boundary conditions were done by Ismo and Ari. But the two communities don't know each other and so they are never cited. Also a way to produce new things...
  • jmlloren on 04 Aug 10
     
    Thanks for noticing! Indeed, I had no idea that Ari (don't know Ismo) was involved in the field. Was it before Kane's proposal or more recently? What I mostly like is that semiconductors are good candidates for 3D TI, however I got lost in the quantum field jargon. Yesterday, I got a headache trying to follow the Majorana fermions, the merons, skyrnions, axions, and so on. Luzi, are all these things familiar to you?
  • Luzi Bergamin on 04 Aug 10
     
    Ismo Lindell described in the early 90's the mirror charge of what is now called topological insulator. He says that similar results were obtained already at the beginning of the 20th century... Ismo Lindell and Ari Sihvola in the recent years discussed engineering aspects of PEMCs (perfect electro-megnetic conductors,) which are more or less classical analogues of topological insulators. Fundamental aspects of PEMCs are well knwon in high-energy physics for a long time, recent works are mainly due to Friedrich Hehl and Yuri Obukhov. All these works are purely classical, so there is no charge quantisation, no considerations of electron spin etc. About Majorana fermions: yes, I spent several years of research on that topic. Axions: a topological state, of course, trivial :-) Also merons and skyrnions are topological states, but I'm less familiar with them.
  • LeopoldS on 04 Aug 10
     
    "Non-Abelian systems1, 2 contain composite particles that are neither fermions nor bosons and have a quantum statistics that is far richer than that offered by the fermion-boson dichotomy. The presence of such quasiparticles manifests itself in two remarkable ways. First, it leads to a degeneracy of the ground state that is not based on simple symmetry considerations and is robust against perturbations and interactions with the environment. Second, an interchange of two quasiparticles does not merely multiply the wavefunction by a sign, as is the case for fermions and bosons. Rather, it takes the system from one ground state to another. If a series of interchanges is made, the final state of the system will depend on the order in which these interchanges are being carried out, in sharp contrast to what happens when similar operations are performed on identical fermions or bosons." wow, this paper by Stern reads really weired ... any of you ever looked into this?
  • jmlloren on 04 Aug 10
     
    C'mon Leopold, it's as trivial as the topological states, AKA axions! Regarding the question, not me!
  • LeopoldS on 04 Aug 10
     
    just looked up the wikipedia entry on axions .... at least they have some creativity in names giving: "In supersymmetric theories the axion has both a scalar and a fermionic superpartner. The fermionic superpartner of the axion is called the axino, the scalar superpartner is called the saxion. In some models, the saxion is the dilaton. They are all bundled up in a chiral superfield. The axino has been predicted to be the lightest supersymmetric particle in such a model.[24] In part due to this property, it is considered a candidate for the composition of dark matter.[25]"
  • jmlloren on 04 Aug 10
     
    Thank's Leopold. Sorry Luzi for being ironic concerning the triviality of the axions. Now, Leo confirmed me that indeed is a trivial matter. I have problems with models where EVERYTHING is involved.
  • Luzi Bergamin on 04 Aug 10
     
    Well, that's the theory of everything, isn't it?? Seriously: I don't think that theoretically there is a lot of new stuff here. Topological aspects of (non-Abelian) theories became extremely popular in the context of string theory. The reason is very simple: topological theories are much simpler than "normal" and since string theory anyway is far too complicated to be solved, people just consider purely topological theories, then claiming that this has something to do with the real world, which of course is plainly wrong. So what I think is new about these topological insulators are the claims that one can actually fabricate a material which more or less accurately mimics a topological theory and that these materials are of practical use. Still, they are a little bit the poor man's version of the topological theories fundamental physicists like to look at since electrdynamics is an Abelian theory.
  • jmlloren on 04 Aug 10
     
    I have the feeling, not the knowledge, that you are right. However, I think that the implications of this light quantum field effects are great. The fact of being able to sustain two currents polarized in spin is a technological breakthrough.
  • LeopoldS on 04 Aug 10
     
    not sure how much I can contribute to your apparently educated debate here but if I remember well from my work for the master, these non-Abelian theories were all but "simple" as Luzi puts it ... and from a different perspective: to me the whole thing of being able to describe such non-Abelian systems nicely indicates that they should in one way or another also have some appearance in Nature (would be very surprised if not) - though this is of course no argument that makes string theory any better or closer to what Luzi called reality ....
  • Luzi Bergamin on 04 Aug 10
     
    Well, electrodynamics remains an Abelian theory. From the theoretical point of view this is less interesting than non-Abelian ones, since in 4D the fibre bundle of a U(1) theory is trivial (great buzz words, eh!) But in topological insulators the point of view is slightly different since one always has the insulator (topological theory), its surrounding (propagating theory) and most importantly the interface between the two. This is a new situation that people from field and string theory were not really interested in.
  • Dario Izzo on 04 Aug 10
     
    guys... how would you explain this to your gran mothers?
  • jmlloren on 05 Aug 10
  • LeopoldS on 07 Aug 10
     
    *you* tried *your* best .... ??
pacome delva

Special relativity passes key test - 2 views

physicsworld.com/...40834

phy quantum_gravity special_relativity gamma_ray_burst

shared by pacome delva on 15 Dec 09 - Cached
  • Granot and colleagues studied the radiation from a gamma-ray burst – associated with a highly energetic explosion in a distant galaxy – that was spotted by NASA's Fermi Gamma-ray Space Telescope on 10 May this year. They analysed the radiation at different wavelengths to see whether there were any signs that photons with different energies arrived at Fermi's detectors at different times.
  • According to Granot, these results "strongly disfavour" quantum-gravity theories in which the speed of light varies linearly with photon energy, which might include some variations of string theory or loop quantum gravity. "I would not use the term 'rule out'," he says, "as most models do not have exact predictions for the energy scale associated with this violation of Lorentz invariance. However, our observational requirement that such an energy scale would be well above the Planck energy makes such models unnatural."
  • Dario Izzo on 16 Dec 09
     
    essentially they made an experiment that does not prove or disprove anything -big deal-... what is the scientific value of "strongly disfavour"??? I also like the sentence "most models do not have exact predictions for the energy scale associated with this violation of Lorentz invariance" ... but if this is true WHAT IS THE POINT OF THE EXPERIMENT!!!! God, physics is in trouble ....
  • pacome delva on 17 Dec 09
     
    hum, null result experiments are not useless !!! there is always the hope of finding "something wrong", which would lead to a great discovery. For the state of theoretical physics (the "no exact predictions" quote), i totally agree that physics is in trouble... That's what happen when physicists don't care anymore about experiments...! All you can do now is drawing "nice"graph with upper bounds on some parameters of an all tunable weird theory !
Luís F. Simões

Kaggle: Crowdsourcing Data Modeling - 2 views

www.kaggle.com/aboutus

crowdsourcing competition data mining statistics data database

shared by Luís F. Simões on 05 Jan 11 - No Cached
  • Kaggle is an innovative solution for statistical/analytics outsourcing. We are the leading platform for data modeling and prediction competitions. Companies, governments and researchers present datasets and problems - the world's best data scientists then compete to produce the best solutions. At the end of a competition, the competition host pays prize money in exchange for the intellectual property behind the winning model.
Luzi Bergamin

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

www.nzz.ch/...s_hirnmaschine_1.10736223.html

AI neuroscience SciFi

shared by Luzi Bergamin on 29 May 11 - No Cached
  • Luzi Bergamin on 29 May 11
     
    A critical view on Prof. Markram's Blue Brain project (in German).
  • ...4 more comments...
  • Luzi Bergamin on 29 May 11
     
    A critical view on Prof. Markram's Blue Brain project (in German).
  • LeopoldS on 30 May 11
     
    so critical that the comment needed to be posted twice :-) ?
  • Luzi Bergamin on 30 May 11
     
    Yes, I know; I still don't know how to deal with this f.... Diigo Toolbar! Shame on me!!!
  • dejanpetkow on 30 May 11
     
    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.
  • Ma Ru on 31 May 11
     
    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.
  • Luzi Bergamin on 01 Jun 11
     
    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...
LeopoldS

BBC News - New method 'confirms dark energy' - 3 views

www.bbc.co.uk/...science-environment-13462926

shared by LeopoldS on 20 May 11 - No Cached
  • LeopoldS on 20 May 11
     
    Look at this!!
  • pacome delva on 20 May 11
     
    well, this confirms the standard cosmological model as a coherent model... however who is satisfied with a model where 96% of the content is unknown...?
Ma Ru

IEEE Xplore - Diversity Through Multiculturality: Assessing Migrant Choice Policies in ... - 0 views

ieeexplore.ieee.org/...abs_all.jsp

INF island model migration PaGMO

shared by Ma Ru on 02 Sep 11 - No Cached
  • Ma Ru on 02 Sep 11
     
    Article on migration policies in the island model. Focus on so-called "multikulti" approach which fosters diversification. Interesting quote: "Other possible avenues of research will be to investigate the influence of the topology on the performance, in relation with the average path length from one node to another and in the sense of the general connectivity." Would be indeed...
ESA ACT

JWS Online Cellular Systems Modelling - 0 views

jjj.biochem.sun.ac.za/index.html

BIO biology biomedicine biotechnology BioController mathematics complex_systems computing Research

shared by ESA ACT on 24 Apr 09 - Cached
  • ESA ACT on 24 Apr 09
     
    A database with biological models that can be downloaded or run in the web-browser!
ESA ACT

Nature article on economics and physics - 0 views

www.nature.com/...4551181a.pdf

economy modelling INF physics economics

shared by ESA ACT on 24 Apr 09 - Cached
  • ESA ACT on 24 Apr 09
     
    nice nature article on the need for economics to use more physics in their approach to model markets - LS
nikolas smyrlakis

How Michael Osinski Helped Build the Bomb That Blew Up Wall Street -- New York Magazine - 0 views

nymag.com/55687

crisis software wall street bubble mortgage computational

shared by nikolas smyrlakis on 15 May 09 - Cached
  • You needed models to create the intricate network of bonds based on the homeowners’ payments, models to predict prepayment rates, and models to predict defaults. You needed the Internet to sail these bonds back and forth across the world, massaging their content to fit an investor’s needs at a moment’s notice. Add to all this the complacency, greed, entitlement, and callous stupidity that characterized banks in post-2001 America, and you have a recipe for disaster.
  • nikolas smyrlakis on 15 May 09
     
    CMS !
Luís F. Simões

Robot biologist solves complex problem from scratch - 1 views

www.kurzweilai.net/s-complex-problem-from-scratch

science automation BIO data mining genetic programming

shared by Luís F. Simões on 17 Oct 11 - No Cached
  • Ref.: Michael D Schmidt, et al., Automated refinement and inference of analytical models for metabolic networks, Physical Biology, 2011; 8 (5): 055011 [DOI: 10.1088/1478-3975/8/5/055011]
  • Luís F. Simões on 17 Oct 11
     
    The latest from Schmidt / Lipson / Eureqa. A significant improvement over their previous work is that now "The algorithm selects between multiple candidate models by designing experiments to make their predictions disagree."
LeopoldS

Evidence of Water Vapor in Excess of Saturation in the Atmosphere of Mars - 2 views

www.sciencemag.org/...1868.abstract

science planetary exploration climate modelling

shared by LeopoldS on 25 Oct 11 - No Cached
  • LeopoldS on 25 Oct 11
     
    Cynthia, Marion - have a look at this: I assume that this also affects our model, correct?
  • Marion Nachon on 31 Oct 11
     
    And I suppose they will (or already have) modify their GCM to take this in account...
Dario Izzo

A harsh critics to GCMs from Judith Curry - 2 views

www.thegwpf.org/...Curry-2017.pdf

shared by Dario Izzo on 21 Feb 17 - No Cached
  • Dario Izzo on 21 Feb 17
     
    "By extension, GCMs are not fit for the purpose of justifying political policies to fundamentally alter world social, economic and energy systems. It is this application of climate model results that fuels the vociferousness of the debate surrounding climate models."
  • LeopoldS on 01 Mar 17
     
    but you know wo these global warming policy foundation is, do you? they are the main advocacy group for climate change deniers in the UK, nothing scientific to start with; fine to post here reasonable scientific papers criticising global climate models but please not this shit
Dario Izzo

Global Climate Models Powered by Intel® Xeon Phi™ Coprocessors - 1 views

www.intel.com/...xeon-phi-nasa-sc12-video.html

CPU intel® climate models

shared by Dario Izzo on 05 Mar 13 - No Cached
  • Dario Izzo on 05 Mar 13
     
    NASA has it ... I WANT IT TOO!!!! 240 threads on 60 cores ... Imagine the possibilities of this new toy!! Francesco also has it in his new "kill the seals" job
Isabelle Dicaire

Statistical physics offers a new way to look at climate - 2 views

www.sciencedaily.com/...130305145807.htm

physics climate

shared by Isabelle Dicaire on 07 Mar 13 - No Cached
  • Isabelle Dicaire on 07 Mar 13
     
    New Earth climate model based on statistical physics and available on the App Store !
  • LeopoldS on 10 Mar 13
     
    not overly intuitive ...
Dario Izzo

Climatologists are no Einsteins, says his successor | NJ.com - 2 views

blog.nj.com/...tologists_are_no_einstein.html

climate

shared by Dario Izzo on 08 Apr 13 - No Cached
  • Dario Izzo on 08 Apr 13
     
    I know at least of a few people who share this point of view :)
  • johannessimon81 on 09 Apr 13
     
    I think it is worth noting that Dyson's is not saying that climate change is an illusion - it is evident that a lot of CO2 is emitted into the atmosphere and hence something will change. His point is that we just don't know what will change and by how much and that (much) more experimental data is necessary to make predictive models.
  • johannessimon81 on 11 May 13
     
    On missing experimental work: just read in the news that condensation in cirrus clouds has been studied recently and that the models where incorrect as to what the significance of organic substances and soot is in cirrus cloud formation. http://www.sciencemag.org/content/early/2013/05/08/science.1234145
LeopoldS

Management of trade-offs in geoengineering through optimal choice of non-uniform radiat... - 1 views

www.nature.com/...nclimate1722.html

geoengineering nature climate climate change

shared by LeopoldS on 27 Oct 12 - No Cached
  • LeopoldS on 27 Oct 12
     
    Nice modelling research on geo engineering options ...
jaihobah

Suburban space oddities | 1843 - 0 views

www.1843magazine.com/...suburban-space-oddities

shared by jaihobah on 12 Apr 16 - No Cached
  • jaihobah on 12 Apr 16
     
    "The forecasts were the product of a series of "summer studies" led by NASA's Ames Research Centre and Stanford University, at which top academics, scientists, and engineers gathered to imagine how future space colonies could look. Artists gave life to the blueprints, producing a stunning series of images that look like a cross between CGI real-estate models (complete with would-be residents smugly sipping wine) and the fantastical worlds of Isaac Asimov."
Dario Izzo

Bold title ..... - 3 views

www.extremetech.com/...ow-learn-from-pure-observation

shared by Dario Izzo on 02 Sep 16 - No Cached
  • johannessimon81 on 02 Sep 16
     
    I got a fever. And the only prescription is more cat faces! ...../\_/\ ...(=^_^) ..\\(___) The article sounds quite interesting, though. I think the idea of a "fake" agent that tries to trick the classifier while both co-evolve is nice as it allows the classifier to first cope with the lower order complexity of the problem. As the fake agent mimics the real agent better and better the classifier has time to add complexity to itself instead of trying to do it all at once. It would be interesting if this is later reflected in the neural nets structure, i.e. having core regions that deal with lower order approximation / classification and peripheral regions (added at a later stage) that deal with nuances as they become apparent. Also this approach will develop not just a classifier for agent behavior but at the same time a model of the same. The later may be useful in itself and might in same cases be the actual goal of the "researcher". I suspect, however, that the problem of producing / evolving the "fake agent" model might in most case be at least as hard as producing a working classifier...
  • johannessimon81 on 05 Sep 16
     
    This paper from 2014 seems discribe something pretty similar (except for not using physical robots, etc...): https://papers.nips.cc/paper/5423-generative-adversarial-nets.pdf
  • Paul N on 13 Sep 16
     
    Yes, this IS basically adversarial learning. Except the generator part instead of being a neural net is some kind of swarm parametrization. I just love how they rebranded it, though. :))
jcunha

Breakthrough model biological supercomputer - 4 views

phys.org/...-biological-supercomputer.html

technology science BIO supercomputer parallel ABACUS

shared by jcunha on 04 Mar 16 - No Cached
LeopoldS liked it
  • jcunha on 04 Mar 16
     
    The model bio- supercomputer is powered by adenosine triphosphate (ATP), the substance that provides energy to all of the cells in a human body.
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