Items of some interest:

These are my recent Pin​board​.in links:

  • [1201.5440] Self-​​assembly of anisotropic soft par­ti­cles in two dimensions

    “The self assem­bly of core-​​corona discs inter­act­ing via anisotropic poten­tials is inves­ti­gated using Monte Carlo com­puter sim­u­la­tions. A min­i­mal inter­ac­tion poten­tial that incor­po­rates anisotropy in a sim­ple way is intro­duced. It con­sists in a core-​​corona archi­tec­ture in which the cen­ter of the core is shifted with respect to the cen­ter of the corona. Anisotropy can thus be tuned by pro­gres­sively shift­ing the posi­tion of the core. Despite its sim­plic­ity, the sys­tem self orga­nize in a rich vari­ety of struc­tures includ­ing stripes, tri­an­gu­lar and rec­tan­gu­lar lat­tices, and unusual plas­tic crys­tals. Our results indi­cate that the amount of anisotropy does not alter the lat­tice spac­ing and only influ­ences the type of clus­ter­ing (stripes, micells, etc.) of the indi­vid­ual particles.”

    self-​​assembly biologically-​​inspired sim­u­la­tion pattern-​​formation condensed-​​matter
  • [1201.5477] Entropy-​​growth-​​based model of emo­tion­ally charged online dialogues

    “We ana­lyze emo­tion­ally anno­tated mas­sive data from IRC (Inter­net Relay Chat) and model the dia­logues between its par­tic­i­pants by assum­ing that the dri­ving force for the dis­cus­sion is the entropy growth of emo­tional prob­a­bil­ity dis­tri­b­u­tion. This process is claimed to be cor­re­lated to the emer­gence of the power-​​law dis­tri­b­u­tion of the dis­cus­sion lengths observed in the dia­logues. We per­form numer­i­cal sim­u­la­tions based on the noticed phe­nom­e­non obtain­ing a good agree­ment with the real data. Finally, we pro­pose a method to arti­fi­cially pro­long the dura­tion of the dis­cus­sion that relies on the entropy of emo­tional prob­a­bil­ity distribution.”

    oh-​​look-​​power-​​laws flame-​​wars social-​​dynamics com­plex­ol­ogy cultural-​​dynamics
  • [1201.4955] Coor­di­na­tion, Dif­fer­en­ti­a­tion and Fair­ness in a pop­u­la­tion of coop­er­at­ing agents

    “In a recent paper, we ana­lyzed the self-​​assembly of a com­plex coop­er­a­tion net­work. The net­work was shown to approach a state, where every agent invests the same amount of resources. Nev­er­the­less, highly-​​connected agents arise that extract extra-​​ordinarily high pay­offs while con­tribut­ing com­pa­ra­bly lit­tle to any of their coop­er­a­tions. Here, we inves­ti­gate a vari­ant of the model, in which highly-​​connected agents have access to addi­tional resources. We study ana­lyt­i­cally and numer­i­cally whether these resources are invested in exist­ing col­lab­o­ra­tions, lead­ing to a fairer load dis­tri­b­u­tion, or in estab­lish­ing new col­lab­o­ra­tions, lead­ing to an even less fair dis­tri­b­u­tion of loads and payoffs.”

    col­lab­o­ra­tion social-​​capital agent-​​based network-​​theory com­plex­ol­ogy nudge-​​targets
  • [1201.5426] Con­straint Prop­a­ga­tion as Infor­ma­tion Maximization

    “Dana Scott used the par­tial order among par­tial func­tions for his math­e­mat­i­cal model of recur­sively defined func­tions. He inter­preted the par­tial order as one of infor­ma­tion con­tent. In this paper we elab­o­rate on Scott’s sug­ges­tion of regard­ing com­pu­ta­tion as a process of infor­ma­tion max­i­miza­tion by apply­ing it to the solu­tion of con­straint sat­is­fac­tion prob­lems. Here the method of con­straint prop­a­ga­tion can be inter­preted as decreas­ing uncer­tainty about the solu­tion — that is, as gain in infor­ma­tion about the solu­tion. As illus­tra­tive exam­ple we choose numer­i­cal con­straint sat­is­fac­tion prob­lems to be solved by inter­val con­straints. To facil­i­tate this approach to con­straint solv­ing we for­mu­late con­straint sat­is­fac­tion prob­lems as for­mu­las in pred­i­cate logic. This neces­si­tates extend­ing the usual seman­tics for pred­i­cate logic so that mean­ing is assigned not only to sen­tences but also to for­mu­las with free variables.”

    computer-​​science quite-​​interesting constraint-​​processing computational-​​methods
  • [1201.4459] An effi­cient par­al­lel algo­rithm for the longest path prob­lem in meshes

    “In this paper, first we give a sequen­tial linear-​​time algo­rithm for the longest path prob­lem in meshes. This algo­rithm can be con­sid­ered as an improve­ment of [13]. Then based on this sequen­tial algo­rithm, we present a constant-​​time par­al­lel algo­rithm for the prob­lem which can be run on every par­al­lel machine.”

    algo­rithms graph-​​theory computational-​​complexity nudge-​​targets
  • [1201.4417] Insta­bil­i­ties and Pat­terns in Cou­pled Reaction-​​Diffusion Layers

    “We study insta­bil­i­ties and pat­tern for­ma­tion in reaction-​​diffusion lay­ers that are dif­fu­sively cou­pled. For two-​​layer sys­tems of iden­ti­cal two-​​component reac­tions, we ana­lyze the sta­bil­ity of homo­ge­neous steady states by exploit­ing the block sym­met­ric struc­ture of the lin­ear prob­lem. There are eight pos­si­ble pri­mary bifur­ca­tion sce­nar­ios, includ­ing a Turing-​​Turing bifur­ca­tion that involves two dis­parate length scales whose ratio may be tuned via the inter-​​layer cou­pling. For sys­tems of $n$-component lay­ers and non-​​identical lay­ers, the lin­ear problem’s block form allows approx­i­mate decom­po­si­tion into lower-​​dimensional lin­ear prob­lems if the cou­pling is suf­fi­ciently weak. As an exam­ple, we apply these results to a two-​​layer Brus­se­la­tor sys­tem. The com­pet­ing length scales engi­neered within the lin­ear prob­lem are read­ily appar­ent in numer­i­cal sim­u­la­tions of the full sys­tem. Select­ing a $sqrt{2}$:1 length scale ratio pro­duces an unusual steady square pattern.”

    cute emergent-​​design pattern-​​formation com­plex­ol­ogy nudge-​​targets nonlinear-​​dynamics
  • [1201.4737] Pro­duc­tion Sys­tem Rules as Pro­tein Com­plexes from Genetic Reg­u­la­tory Networks

    “This short paper intro­duces a new way by which to design pro­duc­tion sys­tem rules. An indi­rect encod­ing scheme is pre­sented which views such rules as pro­tein com­plexes pro­duced by the tem­po­ral behav­iour of an arti­fi­cial genetic reg­u­la­tory net­work. This ini­tial study begins by using a sim­ple Boolean reg­u­la­tory net­work to pro­duce tra­di­tional ternary-​​encoded rules before mov­ing to a fuzzy vari­ant to pro­duce real-​​valued rules. Com­pet­i­tive per­for­mance is shown with related genetic reg­u­la­tory net­works and rule-​​based sys­tems on bench­mark problems.”

    evolutionary-​​algorithms production-​​systems computer-​​science emergent-​​design

Items of some interest:

These are my recent Pin​board​.in links:

Items of some interest:

These are my recent Pin​board​.in links:

  • A Way To Think About Online Courses (By Apple, For Exam­ple) | Eas­ily Distracted

    “One thing that struck me dur­ing the meet­ing, though, was that if you cre­ated a really rich body of mate­ri­als that looked some­what like an “online course”, what you really might be doing was craft­ing a com­pletely novel form of pub­li­ca­tion. Imag­ine a work of his­tor­i­cal schol­ar­ship that included video of the author giv­ing an explana­tory lec­ture at the begin­ning of a sec­tion of the read­ing; that had direct links to a huge body of archival pic­tures, audio record­ings, maps, and other sup­port­ing mate­ri­als; that exten­sively linked to rel­e­vant (or com­pet­ing) analy­ses avail­able in dig­i­tal col­lec­tions like JSTOR; and where the author would appear live once every week to take ques­tions from stu­dents read­ing the book in a class.”

    media academic-​​culture ped­a­gogy pub­lish­ing a-​​new-​​tent-​​and-​​a-​​new-​​camel
  • Evo­lu­tion of increased com­plex­ity in a mol­e­c­u­lar machine : Nature : Nature Pub­lish­ing Group

    “Many cel­lu­lar processes are car­ried out by mol­e­c­u­lar ‘machines’—assemblies of mul­ti­ple dif­fer­en­ti­ated pro­teins that phys­i­cally inter­act to exe­cute bio­log­i­cal functions1, 2, 3, 4, 5, 6, 7, 8. Despite much spec­u­la­tion, strong evi­dence of the mech­a­nisms by which these assem­blies evolved is lack­ing. Here we use ances­tral gene resurrection9, 10, 11 and manip­u­la­tive genetic exper­i­ments to deter­mine how the com­plex­ity of an essen­tial mol­e­c­u­lar machine—the hexa­m­eric trans­mem­brane ring of the eukary­otic V-​​ATPase pro­ton pump—increased hun­dreds of mil­lions of years ago. We show that the ring of Fungi, which is com­posed of three par­al­o­gous pro­teins, evolved from a more ancient two-​​paralogue com­plex because of a gene dupli­ca­tion that was fol­lowed by loss in each daugh­ter copy of spe­cific inter­faces by which it inter­acts with other ring pro­teins. These losses were com­ple­men­tary, so both copies became oblig­ate com­po­nents with restricted spa­tial roles in the com­plex. Rein­tro­duc­ing a sin­gle his­tor­i­cal muta­tion from each par­alogue lin­eage into the res­ur­rected ances­tral pro­teins is suf­fi­cient to reca­pit­u­late their asym­met­ric degen­er­a­tion and trig­ger the require­ment for the more elab­o­rate three-​​component ring. Our exper­i­ments show that increased com­plex­ity in an essen­tial mol­e­c­u­lar machine evolved because of sim­ple, high-​​probability evo­lu­tion­ary processes, with­out the appar­ent evo­lu­tion of novel func­tions. They point to a plau­si­ble mech­a­nism for the evo­lu­tion of com­plex­ity in other multi-​​paralogue pro­tein complexes.”

    via:cshalizi evo­lu­tion structural-​​biology par­si­mony dangers-​​of-​​premature-​​optimization lesson-​​for-​​genetic-​​programming

  • geom­e­try sim­u­la­tor nudge-​​targets

Items of some interest:

These are my recent Pin​board​.in links:

Items of some interest:

These are my recent Pin​board​.in links: