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santecarloni

Engineers enlist weather model to optimize offshore wind plan | Stanford School of Engi... - 0 views

engineering.stanford.edu/...el-optimize-offshore-wind-plan

weather wind technology

shared by santecarloni on 21 Mar 12 - No Cached
  • santecarloni on 21 Mar 12
     
    Using a sophisticated weather model, environmental engineers at Stanford have defined optimal placement of a grid of four wind farms off the U.S. East Coast. The model successfully balances production at times of peak demand and significantly reduces costly spikes and zero-power events.
Francesco Biscani

Pi Computation Record - 4 views

bellard.org/pi2700e9

inf

shared by Francesco Biscani on 06 Jan 10 - Cached
  • Francesco Biscani on 06 Jan 10
     
    For Dario: the PI computation record was established on a single desktop computer using a cache optimized algorithm. Previous record was obtained by a cluster of hundreds of computers. The cache optimized algorithm was 20 times faster.
  • ...6 more comments...
  • Ma Ru on 06 Jan 10
     
    Teeeeheeeeheeee... assembler programmers greet Java/Python/Etc. programmers :)
  • Dario Izzo on 07 Jan 10
     
    And he seems to have done everything in his free time!!! I like the first FAQ.... "why did you do it?"
  • nikolas smyrlakis on 07 Jan 10
  • LeopoldS on 07 Jan 10
     
    did you read any of the books he recommends? suggest: Modern Computer Arithmetic by Richard Brent and Paul Zimmermann, version 0.4, November 2009, Full text available here. The Art of Computer Programming, volume 2 : Seminumerical Algorithms by Donald E. Knuth, Addison-Wesley, third edition, 1998. More information here.
  • LeopoldS on 07 Jan 10
     
    btw: we will very soon have the very same processor in the new iMac .... what record are you going to beat with it?
  • Francesco Biscani on 08 Jan 10
     
    Zimmerman is the same guy behind the MPFR multiprecision floating-point library, if I recall correctly: http://www.mpfr.org/credit.html I've not read the book... Multiprecision arithmetic is a huge topic though, at least from the scientific and number theory point of view if not for its applications to engineering problems. "The art of computer programming" is probably the closest thing to a bible for computer scientists :)
  • Francesco Biscani on 08 Jan 10
     
    "btw: we will very soon have the very same processor in the new iMac .... what record are you going to beat with it?" Fastest Linux install on an iMac :)
  • Juxi Leitner on 08 Jan 10
     
    "Fastest Linux install on an iMac :)" that is going to be a though one but a worthy aim! ""The art of computer programming" is probably the closest thing to a bible for computer scientists :)" yep! Programming is art ;)
Dario Izzo

Robotics and optimal control - 6 views

www.cs.washington.edu/...todorov

AI MAD

shared by Dario Izzo on 18 Jan 11 - No Cached
Joris _ and Juxi Leitner liked it
  • Dario Izzo on 18 Jan 11
     
    Home page of teodorov.... He believes optimal control is the path to robot movement.... Not AI!!!
  • ...1 more comment...
  • Juxi Leitner on 18 Jan 11
     
    we were having a discussion about that here recently =) will look into that, grazie mille
  • Joris _ on 18 Jan 11
     
    Isn't it obvious! :)
  • Dario Izzo on 20 Jan 11
     
    I need to modify the first comment "He belives the path to AI goes through optimal control"... Big difference...
Luís F. Simões

Evolution of AI Interplanetary Trajectories Reaches Human-Competitive Levels - Slashdot - 4 views

science.slashdot.org/...aches-human-competitive-levels

AI MAD GTOC PaGMO evolutionary computation trajectory optimization awards

shared by Luís F. Simões on 19 Jul 13 - No Cached
  • "It's not the Turing test just yet, but in one more domain, AI is becoming increasingly competitive with humans. This time around, it's in interplanetary trajectory optimization. From the European Space Agency comes the news that researchers from its Advanced Concepts Team have recently won the Gold 'Humies' award for their use of Evolutionary Algorithms to design a spacecraft's trajectory for exploring the Galilean moons of Jupiter (Io, Europa, Ganymede and Callisto). The problem addressed in the awarded article (PDF) was put forward by NASA/JPL in the latest edition of the Global Trajectory Optimization Competition. The team from ESA was able to automatically evolve a solution that outperforms all the entries submitted to the competition by human experts from across the world. Interestingly, as noted in the presentation to the award's jury (PDF), the team conducted their work on top of open-source tools (PaGMO / PyGMO and PyKEP)."
  • Luís F. Simões on 19 Jul 13
     
    We made it to Slashdot's frontpage !!! :)
  • Ma Ru on 23 Jul 13
     
    Congratulations, gentlemen!
Dario Izzo

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

math.u-bourgogne.fr/...research

OCP CR3BP trajectory MAD

shared by Dario Izzo on 07 Jun 11 - No Cached
  • Dario Izzo on 07 Jun 11
     
    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...
  • Ma Ru on 08 Jun 11
     
    Riemann hypothesis should be next... Which paper on the linked website is this exactly?
  • Joris _ on 08 Jun 11
     
    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 :)
  • Dario Izzo on 08 Jun 11
     
    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 :)
  • Dario Izzo on 08 Jun 11
     
    Answer to Marek: the paper you may look at is: Discrete and differential homotopy in circular restricted three-body control
  • Joris _ on 08 Jun 11
     
    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.
  • Joris _ on 08 Jun 11
     
    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
  • Dario Izzo on 08 Jun 11
     
    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!!!!!"
  • Joris _ on 09 Jun 11
     
    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:)
  • Dario Izzo on 09 Jun 11
     
    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!!
  • Joris _ on 09 Jun 11
     
    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!
  • Dario Izzo on 09 Jun 11
     
    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)
  • LeopoldS on 11 Jun 11
     
    this is why I like this Diigo thingy so much more than delicious ...
  • tvinko on 17 Jun 11
     
    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.)
  • LeopoldS on 18 Jun 11
     
    I like when there are discussions evolving around entries
  • LeopoldS on 18 Jun 11
     
    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 ...
Francesco Biscani

Gamers beat algorithms at finding protein structures - 0 views

arstechnica.com/...finding-protein-structures.ars

inf

shared by Francesco Biscani on 04 Aug 10 - Cached
  • Foldit takes a hybrid approach. The Rosetta algorithm is used to create some potential starting structures, but users are then given a set of controls that let them poke and prod the protein's structure in three dimensions; displays provide live feedback on the energy of a configuration. 
  • By tracing the actions of the best players, the authors were able to figure out how the humans' excellent pattern recognition abilities gave them an edge over the computer.
  • Humans turn out to be really bad at starting from a simple linear chain of proteins; they need a rough idea of what the protein might look like before they can recognize patterns to optimize. Given a set of 10 potential structures produced by Rosetta, however, the best players were very adept at picking the one closest to the optimal configuration.
  • ...1 more annotation...
  • The authors also note that different players tended to have different strengths. Some were better at making the big adjustments needed to get near an energy minimum, while others enjoyed the fine-scale tweaking needed to fully optimize the structure. That's where Foldit's ability to enable team competitions, where different team members could handle the parts of the task most suited to their interests and abilities, really paid off.
  • Francesco Biscani on 04 Aug 10
     
    Some interesting ideas for our crowdsourcing game in here.
dejanpetkow

Metamaterials + Wireless Power Transfer - 2 views

www.sciencedaily.com/...140110153201.htm

technology science phy

shared by dejanpetkow on 21 Jan 14 - No Cached
LeopoldS liked it
  • dejanpetkow on 21 Jan 14
     
    Put together two ACT topics and see what happens.
  • LeopoldS on 22 Jan 14
     
    I remember discussing this briefly and then discarding the idea - but don't remember why any more; duncan?
  • Thijs Versloot on 23 Jan 14
     
    Well, I think that although the antenna is small, you counteract this with a much large metameterial lens. Probably if you design an antenna of a similar size to the 'lens' you can couple power equally well over the same distance. Then again, further optimization might help improve the size. Maybe in the end you want to combine both together, optimization of the antenna, including a metamaterials lens.
Tobias Seidl

Efficient computation of optimal actions - 0 views

www.pnas.org/...11478.abstract

BIO AI INF decision learning paper optimal

shared by Tobias Seidl on 15 Jul 09 - Cached
  • Tobias Seidl on 15 Jul 09
     
    Is this bullshit or really useful?
ESA ACT

Nonradiative Resonant Excitation Transfer from Nanocrystal Quantum Dots to Adjacent Qua... - 0 views

pubs.acs.org/...nl0719731.html

nan energy

shared by ESA ACT on 24 Apr 09 - No Cached
  • ESA ACT on 24 Apr 09
     
    Nonradiative resonant energy transfer in optimized QD-QW systems may provide a solar energy conversion approach with a viable tradeoff with the bottlenecks of charge carrier generation and/or transport to/in electrodes faced by excitonic solar cells.
ESA ACT

European Control Conference 2007 (ECC'07) - 0 views

ecc07.ntua.gr/workshops.html

INF conference control interval

shared by ESA ACT on 24 Apr 09 - Cached
  • ESA ACT on 24 Apr 09
     
    at least we can see how is important in (optimal) control using intervals
Ma Ru

An Inflationary Differential Evolution Algorithm for Space Trajectory Optimization - 7 views

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

space trajectory optimization differential evolution PaGMO INF

shared by Ma Ru on 21 Apr 11 - No Cached
LeopoldS liked it
  • Ma Ru on 21 Apr 11
     
    I was so shocked not to see Dario in the authors list!
  • LeopoldS on 22 Apr 11
     
    still practically as an ACT paper ... the first author was the first RF of the team and the one who suggested Dario ...
  • Ma Ru on 22 Apr 11
     
    Yeah I've figured it out from his CV at the end of the article after posting :)
LeopoldS

Faster optimization | MIT News - 1 views

news.mit.edu/...er-optimization-algorithm-1023

optimisation

shared by LeopoldS on 26 Oct 15 - No Cached
  • LeopoldS on 26 Oct 15
     
    is this really as revolutionary as praised? optimisation guys please ... full paper here: http://arxiv.org/pdf/1508.04874v1.pdf
  • tvinko on 27 Oct 15
     
    They use a 'separation oracle' meaning that the paper is theoretical.
Marcus Maertens

Darwinian data structure selection | the morning paper - 1 views

blog.acolyer.org/...inian-data-structure-selection

INF

shared by Marcus Maertens on 14 Dec 18 - No Cached
mkisantal liked it
  • Marcus Maertens on 14 Dec 18
     
    What happens if you strap NSGA-II to optimize the usage of your abstract data structures?
darioizzo2

Optimised spatial planning to meet long term urban sustainability objectives - ScienceD... - 3 views

www.sciencedirect.com/...S0198971515300090

shared by darioizzo2 on 18 Jan 19 - No Cached
  • darioizzo2 on 18 Jan 19
     
    for the ACT architects .... Can we do the same for the Moon Village? We brainstorm on some mathematical simplified objectives for growing the settlement (taking inputs from the modular growth, resources, terrain suitability etc ....), we define some simple rules for growth and we optimize. ..... easy peasy (i am serious)
  • marliesarnhof on 21 Jan 19
     
    i agree, with most of the parameters that would actually be really cool. but doesn't it get very messy once economy plays a large factor?
  • darioizzo2 on 21 Jan 19
     
    We can start studying the ideal case, or add also some economical constraints on the settlement layout ...
eblazquez

[2106.09125] Convex Optimization for Trajectory Generation - 0 views

arxiv.org/2106.09125

Optimization

shared by eblazquez on 16 Sep 21 - No Cached
  • eblazquez on 16 Sep 21
     
    Very cool recap document on state of the art sequential convex programming and lossless convexification techniques. It's written by the main authors who work on these, worth a look if you're into autonomous trajectory planning.
Joris _

NASA International Space Station Longeron Marathon Challenge - 1 views

www.topcoder.com/iss

MAD optimization

shared by Joris _ on 18 Jan 13 - No Cached
LeopoldS liked it
  • LeopoldS on 19 Jan 13
     
    nice - did not know about it. GTOC on steroids and with loads of cash. concerning this specific challenge and especially the last condition: doesn't this hint towards a flawed design? In addition to maximizing the total power output there are some constraints on the possible movements: Each SARJ and BGA is limited to a maximum angular velocity and to a maximum angular acceleration. Each SAW must produce at least some minimum average power over the orbit (which is different for each SAW). The sequence of positions must be cyclic, so it can be repeated on the next orbit. The maximum amount of BGA rotation is not limited, but exceeding a threshold will result in a score penalty. Some structural members of the SAW mast (called Longerons) have restrictions on how they can be shadowed.
  • Joris _ on 26 Jan 13
     
    The longerons will expand and contract with exposition to sun (I think whatever the material they are made of). Because you have 4 longerons in a mast, you just need to be carefull that the mast is well balanced, and that the 4 longerons support each other, basically, you need an even number of shadowed longerons, possibly 0 too. I would call this an operational constraint.
Annalisa Riccardi

An open-source MDAO framework written in Python - 1 views

openmdao.org

shared by Annalisa Riccardi on 03 Apr 13 - No Cached
LeopoldS liked it
  • Annalisa Riccardi on 03 Apr 13
     
    Multidisciplinary Design Analysis and Optimization framework developed by NASA since 2010
Guido de Croon

Bumblebees tackling the travelling salesman problem - 2 views

www.plosbiology.org/...10.1371%2Fjournal.pbio.1001392

bio science

shared by Guido de Croon on 01 Oct 12 - No Cached
  • Guido de Croon on 01 Oct 12
     
    Nice article on how bumblebees optimize their path from flower to flower.
johannessimon81

Automatic porting of C++ to javascript - 1 views

blog.mozilla.org/...the-release-version-of-firefox

programming web-dev

shared by johannessimon81 on 27 Jun 13 - No Cached
  • johannessimon81 on 27 Jun 13
     
    asm.js: it's really fast, backwards compatible, and now in the release version of Firefox. "By doing this the result is highly optimized and can be converted directly from this Asm.js syntax directly into ASSEMBLY without having to interpret it, as one would normally have to do with JavaScript" Here is great introduction to asm.js and C++ to js compilation: http://ejohn.org/blog/asmjs-javascript-compile-target
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