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johannessimon81

The anternet - the signals network of ants - 3 views

www.wired.com/...-dont-the-future-of-networking

INF AI bio

shared by johannessimon81 on 08 Jul 13 - No Cached
  • Beniamino Abis on 08 Jul 13
     
    The algorithm that regulates the flow of ants is evolving toward minimizing operating costs rather than immediate accumulation.
  • johannessimon81 on 23 Sep 13
     
    Turns out even ants can profit from a siesta on a hot day and they use network security and repair mechanisms. Maybe there is still something undiscovered that we can apply for our own networks.
jcunha

For this metal, electricity flows, but not the heat - 0 views

phys.org/...2017-01-metal-electricity.html

vanadium electrical conduction

shared by jcunha on 30 Jan 17 - No Cached
  • jcunha on 30 Jan 17
     
    A good electrical conductor is normally a good heat conductor. Vanadium dioxide however seems to not be so, by being a good electrical conductor and a poor thermal conductor. Paper at http://science.sciencemag.org/content/355/6323/371
Athanasia Nikolaou

Schrödinger's Smoke - 1 views

www.youtube.com/watch

PHY superfluids science

shared by Athanasia Nikolaou on 13 Jul 16 - No Cached
  • Athanasia Nikolaou on 13 Jul 16
     
    A team of researchers in TU berlin and Caltech used Schrödinger's equation to visualise superfluidic flow (fluids with zero viscosity). Smoke and dry ice are close to this state in nature. Strangely enough for an equation that describes subatomic particles, it works, and reproduces experimental results better that Euler and Langrange schemes.
jcunha

New method uses heat flow to levitate variety of objects - 1 views

phys.org/...2-method-levitate-variety.html

technology science PHY microgravity

shared by jcunha on 16 Feb 17 - No Cached
  • jcunha on 16 Feb 17
     
    Normally we associate levitation of objects to superconducting materials. Here a new technique is shown where levitation of a whole new range of materials is shown. "The large temperature gradient leads to a force that balances gravity and results in stable levitation," said Fung, the study's lead author. "We managed to quantify the thermophoretic force and found reasonable agreement with what is predicted by theory. This will allow us to explore the possibilities of levitating different types of objects." Paper at http://aip.scitation.org/doi/10.1063/1.4974489 New microgravity experiments possibility?
  • LeopoldS on 01 Mar 17
     
    not really I fear .... "Typical sizes of the trapped particles are between 10 μm and 1 mm at a pressure between 1 and 10 Torr. The trapping stability is provided radially by the increasing temperature field and vertically by the transition from the free molecule to hydrodynamic behavior of thermophoresis as the particles ascend."
  • jcunha on 06 Mar 17
     
    Might still be OK micro to mm sized experiments. The technique seems to be reliable and cheap enough to compete with other types of microgravity approaches - more research needed to define boundaries of course.
pandomilla

Not a scratch - 7 views

www.economist.com/21545971

BIO

shared by pandomilla on 12 Apr 12 - No Cached
LeopoldS liked it
  • pandomilla on 12 Apr 12
     
    I hate scorpions, but this could be a nice subject for a future Ariadna study! This north African desert scorpion, doesn't dig burrows to protect itself from the sand-laden wind (as the other scorpions do). When the sand whips by at speeds that would strip paint away from steel, the scorpion is able to scurry off without apparent damage.
  • LeopoldS on 13 Apr 12
     
    Nice research, though they have done almost all the work that we could do in an Ariadna, didnt they? "To check, they took further photographs. In particular, they used a laser scanning system to make a three-dimensional map of the armour and then plugged the result into a computer program that blasted the virtual armour with virtual sand grains at various angles of attack. This process revealed that the granules were disturbing the air flow near the skeleton's surface in ways that appeared to be reducing the erosion rate. Their model suggested that if scorpion exoskeletons were smooth, they would experience almost twice the erosion rate that they actually do. Having tried things out in a computer, the team then tried them for real. They placed samples of steel in a wind tunnel and fired grains of sand at them using compressed air. One piece of steel was smooth, but the others had grooves of different heights, widths and separations, inspired by scorpion exoskeleton, etched onto their surfaces. Each sample was exposed to the lab-generated sandstorm for five minutes and then weighed to find out how badly it had been eroded. The upshot was that the pattern most resembling scorpion armour-with grooves that were 2mm apart, 5mm wide and 4mm high-proved best able to withstand the assault. Though not as good as the computer model suggested real scorpion geometry is, such grooving nevertheless cut erosion by a fifth, compared with a smooth steel surface. The lesson for aircraft makers, Dr Han suggests, is that a little surface irregularity might help to prolong the active lives of planes and helicopters, as well as those of scorpions."
  • Ma Ru on 13 Apr 12
     
    What bugs me (pardon the pun) is that the dimensions of the pattern they used were scaled up by many orders of magnitude, while "grains of sand" with which the surface was bombarded apparently were not... Not being a specialist in the field, I would nevertheless expect that the size of the surface pattern *in relation to* to size of particles used for bombarding would be crucial.
johannessimon81

NASA's Newest Autonomous Lander Passes Flight Test - 1 views

www.wired.com/...mighty-eagle-soars-high

AI space technology science INF

shared by johannessimon81 on 10 Sep 12 - No Cached
LeopoldS liked it
  • johannessimon81 on 10 Sep 12
  • LeopoldS on 10 Sep 12
     
    Why don't they use time to contact / optical flow ... Guido!!!!!!
pacome delva

[1107.5728] The network of global corporate control - 1 views

arxiv.org/1107.5728

economics social_network

shared by pacome delva on 28 Nov 11 - No Cached
  • Abstract: The structure of the control network of transnational corporations affects global market competition and financial stability. So far, only small national samples were studied and there was no appropriate methodology to assess control globally. We present the first investigation of the architecture of the international ownership network, along with the computation of the control held by each global player. We find that transnational corporations form a giant bow-tie structure and that a large portion of control flows to a small tightly-knit core of financial institutions. This core can be seen as an economic "super-entity" that raises new important issues both for researchers and policy makers.
Tom Gheysens

Cheap battery stores energy for a rainy day : Nature News & Comment - 0 views

www.nature.com/...energy-for-a-rainy-day-1.14486

energy battery science phy nature

shared by Tom Gheysens on 16 Jan 14 - No Cached
  • Tom Gheysens on 16 Jan 14
     
    Thijs interested? quinones are my field
  • Thijs Versloot on 20 Jan 14
     
    I think the major benefit of this system is the low cost of the products involved compared to standard flow batteries. However, two issues still remain, corrosion and size. I think these things need to be big right due to the volumetric storage using quinones? Nevertheless, it is interesting to see where this development will lead to. "The system is far from perfect, however: bromine and hydrobromic acid are corrosive, and could cause serious pollution if they leaked. "The bromine is, right now, the Achilles heel of this particular battery," Aziz says. The answer could be to go completely organic, he adds: "We are working on replacing the bromine with a different quinone." Are there quinones which would not be corrosive but retain good volumetric performance?
Marcus Maertens

World First: 3D Acoustic Cloaking Device | I Fucking Love Science - 1 views

www.iflscience.com/...st-3d-acoustic-cloaking-device

PHY science

shared by Marcus Maertens on 14 Mar 14 - No Cached
  • Marcus Maertens on 14 Mar 14
     
    Old news... Sante was doing this 10 years ago! And why does their metamaterial look like a pyramid?
  • johannessimon81 on 14 Mar 14
     
    According to Terry Pratchett pyramids affect the flow of time. Using this, any kind of cloaking device should be trivial.
Guido de Croon

Will robots be smarter than humans by 2029? - 2 views

robohub.org/be-smarter-than-humans-by-2029

AI

shared by Guido de Croon on 10 Mar 14 - No Cached
  • Guido de Croon on 10 Mar 14
     
    Nice discussion about the singularity. Made me think of drinking coffee with Luis... It raises some issues such as the necessity of embodiment, etc.
  • ...9 more comments...
  • Luís F. Simões on 12 Mar 14
     
    "Kurzweilians"... LOL. Still not sold on embodiment, btw.
  • Ma Ru on 12 Mar 14
     
    The biggest problem with embodiment is that, since the passive walkers (with which it all started), it hasn't delivered anything really interesting...
  • Paul N on 13 Mar 14
     
    The problem with embodiment is that it's done wrong. Embodiment needs to be treated like big data. More sensors, more data, more processing. Just putting a computer in a robot with a camera and microphone is not embodiment.
  • Marcus Maertens on 14 Mar 14
     
    I like how he attacks Moore's Law. It always looks a bit naive to me if people start to (ab)use it to make their point. No strong opinion about embodiment.
  • johannessimon81 on 14 Mar 14
     
    @Paul: How would embodiment be done RIGHT?
  • Guido de Croon on 16 Mar 14
     
    Embodiment has some obvious advantages. For example, in the vision domain many hard problems become easy when you have a body with which you can take actions (like looking at an object you don't immediately recognize from a different angle) - a point already made by researchers such as Aloimonos.and Ballard in the end 80s / beginning 90s. However, embodiment goes further than gathering information and "mental" recognition. In this respect, the evolutionary robotics work by for example Beer is interesting, where an agent discriminates between diamonds and circles by avoiding one and catching the other, without there being a clear "moment" in which the recognition takes place. "Recognition" is a behavioral property there, for which embodiment is obviously important. With embodiment the effort for recognizing an object behaviorally can be divided between the brain and the body, resulting in less computation for the brain. Also the article "Behavioural Categorisation: Behaviour makes up for bad vision" is interesting in this respect. In the field of embodied cognitive science, some say that recognition is constituted by the activation of sensorimotor correlations. I wonder to which extent this is true, and if it is valid for extremely simple creatures to more advanced ones, but it is an interesting idea nonetheless. This being said, if "embodiment" implies having a physical body, then I would argue that it is not a necessary requirement for intelligence. "Situatedness", being able to take (virtual or real) "actions" that influence the "inputs", may be.
  • Ma Ru on 17 Mar 14
     
    @Paul While I completely agree about the "embodiment done wrong" (or at least "not exactly correct") part, what you say goes exactly against one of the major claims which are connected with the notion of embodiment (google for "representational bottleneck"). The fact is your brain does *not* have resources to deal with big data. The idea therefore is that it is the body what helps to deal with what to a computer scientist appears like "big data". Understanding how this happens is key. Whether it is the problem of scale or of actually understanding what happens should be quite conclusively shown by the outcomes of the Blue Brain project.
  • johannessimon81 on 17 Mar 14
     
    Wouldn't one expect that to produce consciousness (even in a lower form) an approach resembling that of nature would be essential? All animals grow from a very simple initial state (just a few cells) and have only a very limited number of sensors AND processing units. This would allow for a fairly simple way to create simple neural networks and to start up stable neural excitation patterns. Over time as complexity of the body (sensors, processors, actuators) increases the system should be able to adapt in a continuous manner and increase its degree of self-awareness and consciousness. On the other hand, building a simulated brain that resembles (parts of) the human one in its final state seems to me like taking a person who is just dead and trying to restart the brain by means of electric shocks.
  • Paul N on 17 Mar 14
     
    Actually on a neuronal level all information gets processed. Not all of it makes it into "conscious" processing or attention. Whatever makes it into conscious processing is a highly reduced representation of the data you get. However that doesn't get lost. Basic, low processed data forms the basis of proprioception and reflexes. Every step you take is a macro command your brain issues to the intricate sensory-motor system that puts your legs in motion by actuating every muscle and correcting every step deviation from its desired trajectory using the complicated system of nerve endings and motor commands. Reflexes which were build over the years, as those massive amounts of data slowly get integrated into the nervous system and the the incipient parts of the brain. But without all those sensors scattered throughout the body, all the little inputs in massive amounts that slowly get filtered through, you would not be able to experience your body, and experience the world. Every concept that you conjure up from your mind is a sort of loose association of your sensorimotor input. How can a robot understand the concept of a strawberry if all it can perceive of it is its shape and color and maybe the sound that it makes as it gets squished? How can you understand the "abstract" notion of strawberry without the incredibly sensible tactile feel, without the act of ripping off the stem, without the motor action of taking it to our mouths, without its texture and taste? When we as humans summon the strawberry thought, all of these concepts and ideas converge (distributed throughout the neurons in our minds) to form this abstract concept formed out of all of these many many correlations. A robot with no touch, no taste, no delicate articulate motions, no "serious" way to interact with and perceive its environment, no massive flow of information from which to chose and and reduce, will never attain human level intelligence. That's point 1. Point 2 is that mere pattern recogn
  • Ma Ru on 18 Mar 14
     
    All information *that gets processed* gets processed but now we arrived at a tautology. The whole problem is ultimately nobody knows what gets processed (not to mention how). In fact an absolute statement "all information" gets processed is very easy to dismiss because the characteristics of our sensors are such that a lot of information is filtered out already at the input level (e.g. eyes). I'm not saying it's not a valid and even interesting assumption, but it's still just an assumption and the next step is to explore scientifically where it leads you. And until you show its superiority experimentally it's as good as all other alternative assumptions you can make. I only wanted to point out is that "more processing" is not exactly compatible with some of the fundamental assumptions of the embodiment. I recommend Wilson, 2002 as a crash course.
  • Paul N on 24 Mar 14
     
    These deal with different things in human intelligence. One is the depth of the intelligence (how much of the bigger picture can you see, how abstract can you form concept and ideas), another is the breadth of the intelligence (how well can you actually generalize, how encompassing those concepts are and what is the level of detail in which you perceive all the information you have) and another is the relevance of the information (this is where the embodiment comes in. What you do is to a purpose, tied into the environment and ultimately linked to survival). As far as I see it, these form the pillars of human intelligence, and of the intelligence of biological beings. They are quite contradictory to each other mainly due to physical constraints (such as for example energy usage, and training time). "More processing" is not exactly compatible with some aspects of embodiment, but it is important for human level intelligence. Embodiment is necessary for establishing an environmental context of actions, a constraint space if you will, failure of human minds (i.e. schizophrenia) is ultimately a failure of perceived embodiment. What we do know is that we perform a lot of compression and a lot of integration on a lot of data in an environmental coupling. Imo, take any of these parts out, and you cannot attain human+ intelligence. Vary the quantities and you'll obtain different manifestations of intelligence, from cockroach to cat to google to random quake bot. Increase them all beyond human levels and you're on your way towards the singularity.
johannessimon81

High efficiency solid state heat engine - 0 views

www.parc.com/...ciency-solid-state-engine.html

nrg technology

shared by johannessimon81 on 22 Aug 13 - No Cached
  • johannessimon81 on 22 Aug 13
     
    We discussed this today during coffee. The inventor claims that he claims that a pressure differential can push hydrogen through a proton conductive membrane (thereby stripping off the electrons) which flow through an electric circuit and provide electric power. The type of membrane is fairly similar to that found in a hydrogen fuel cell. If the pressure differential is cause by selective heating this is in essence a heat engine that directly produces electricity. The inventor claims that this could be a high efficiency alternative to thermoelectric devices and could even outperform PV and Sterling engines with an efficiency close to that of fuel cells (e.g., ~60% @ dT=600K). I could not find any scientific publications as the inventor is not affiliated to any University - he has however an impressive number of patents from a very wide field (e.g., the "Super Soaker" squirt gun) and has worked on several NASA and US military projects. His current research seams to be funded by the latter as well. Here are some more links that I found: http://www.theatlantic.com/magazine/archive/2010/11/shooting-for-the-sun/308268/ http://www.johnsonems.com/?q=node/13 http://scholar.google.nl/scholar?q=%22lonnie+g+johnson%22+&btnG=&hl=nl&as_sdt=0%2C5
Thijs Versloot

Word of the day - thermoelectric magnetohydrodynamic flow - 1 views

physics.aps.org/st8

fusion MHD

shared by Thijs Versloot on 10 Dec 13 - No Cached
  • Thijs Versloot on 10 Dec 13
     
    Heat and a magnetic field cause the liquid lithium to swirl rapidly, an effect that could be useful in fusion reactors. With a nice video http://physics.aps.org/assets/eab7d11d-20cd-4c37-ab2c-313729ad8422/video-v1.mp4
Thijs Versloot

Forget 3D printing, here is solar printing - 3 views

www.sciencedaily.com/...140403132353.htm

solar energy

shared by Thijs Versloot on 04 Apr 14 - No Cached
LeopoldS liked it
  • Thijs Versloot on 04 Apr 14
     
    The work is based on the use of a "continuous flow" microreactor to produce nanoparticle inks that make solar cells by printing. In this process, simulated sunlight is focused on the solar microreactor to rapidly heat it, while allowing precise control of temperature to aid the quality of the finished product. The light in these experiments was produced artificially, but the process could be done with direct sunlight, and at a fraction of the cost of current approaches.
  • LeopoldS on 09 Apr 14
     
    anybody interested in having a closer look at this?
Beniamino Abis

The Wisdom of (Little) Crowds - 1 views

phenomena.nationalgeographic.com/...the-wisdom-of-little-crowds

BIO science math groups

shared by Beniamino Abis on 30 Apr 14 - No Cached
Dario Izzo liked it
  • Beniamino Abis on 30 Apr 14
     
    What is the best (wisest) size for a group of individuals? Couzin and Kao put together a series of mathematical models that included correlation and several cues. In one model, for example, a group of animals had to choose between two options-think of two places to find food. But the cues for each choice were not equally reliable, nor were they equally correlated. The scientists found that in these models, a group was more likely to choose the superior option than an individual. Common experience will make us expect that the bigger the group got, the wiser it would become. But they found something very different. Small groups did better than individuals. But bigger groups did not do better than small groups. In fact, they did worse. A group of 5 to 20 individuals made better decisions than an infinitely large crowd. The problem with big groups is this: a faction of the group will follow correlated cues-in other words, the cues that look the same to many individuals. If a correlated cue is misleading, it may cause the whole faction to cast the wrong vote. Couzin and Kao found that this faction can drown out the diversity of information coming from the uncorrelated cue. And this problem only gets worse as the group gets bigger.
  • Dario Izzo on 02 May 14
     
    Couzin research was the starting point that co-inspired PaGMO from the very beginning. We invited him (and he came) at a formation flying conference for a plenary here in ESTEC. You can see PaGMO as a collective problem solving simulation. In that respect, we learned already that the size of the group and its internal structure (topology) counts and cannot be too large or too random. One of the project the ACT is running (and currently seeking for new ideas/actors) is briefly described here (http://esa.github.io/pygmo/examples/example2.html) and attempts answering the question :"How is collective decision making influenced by the information flow through the group?" by looking at complex simulations of large 'archipelagos'.
Nina Nadine Ridder

Surprising similarity in fly and mouse motion vision - 2 views

medicalxpress.com/...arity-mouse-motion-vision.html

BIO science evolution biomimetics vision

shared by Nina Nadine Ridder on 30 Jul 15 - No Cached
  • Nina Nadine Ridder on 30 Jul 15
     
    Loosely related to an old ACT project on optical flow (if I remember correctly but even if not still an interesting read I think): "At first glance, the eyes of mammals and those of insects do not seem to have much in common. However, a comparison of the neural circuits for detecting motion shows surprising parallels between flies and mice. Scientists have learned a lot about the visual perception of both animals in recent years."
pacome delva

Physics - Small-scale hydraulics - 1 views

physics.aps.org/...PhysRevLett.103.144503

phy nan nanofluidic bio

shared by pacome delva on 07 Oct 09 - Cached
  • Taking a cue from biology, scientists are now designing nanofluidic devices in which molecular interactions at the walls of a narrow channel are engineered to control fluid flow.
pacome delva

You Are Now Free to Move About the Insect - ScienceNOW - 1 views

news.sciencemag.org/...-now-free-to-move-about-t.html

bio flies optic_flow

shared by pacome delva on 24 Aug 10 - Cached
  • Researchers thought that flies chose their altitude based on optic flow, a phenomenon familiar to anyone who has ridden an airplane.
  • The team's observations, published online today in Current Biology, suggest that flies base their cruising altitude on horizontal edges and landmarks—such as table surfaces or tree tops—and not on how fast the ground is moving beneath them. The edge-tracking strategy may enable flies to keep tabs on possible landing spots.
  • This may be the general principle" for all flying insects, he says.
nikolas smyrlakis

Europe's Ambitious 'Green Grid' Plan - BusinessWeek - 2 views

www.businessweek.com/...gb2010017_256132.htm

smartgrid renewable energy north sea

shared by nikolas smyrlakis on 08 Jan 10 - Cached
  • nikolas smyrlakis on 08 Jan 10
     
    The cables would link existing and new windmills off the German and British coasts with Belgian and Danish tidal power stations and Norwegian hydroelectric plants. The €30-billion project would compensate for the irregular nature of renewable energy and provide a steady flow to the countries involved.
pacome delva

Mapping Turbulence in the Solar Wind - 0 views

focus.aps.org/st16

phy astrophysics solar_wind formation_flying turbulence

shared by pacome delva on 03 May 10 - Cached
  • a team reports studying the turbulent flow of solar wind particles by monitoring the accompanying waves of magnetic field. The team used a cluster of satellites to measure the field in unprecedented spatial detail. They found that the waves aren't equally strong in all directions but are larger in certain preferred directions, as theorists had predicted. The observation will help astrophysicists better understand the consequences of the solar wind, including its effect on the transmission of cosmic rays, particles that arrive at Earth from elsewhere in our galaxy.
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