Items of some interest:

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

Items of some interest:

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

  • Jonathan Lethem’s ‘Neote­nous Aes­thetic” — Mis­ter Bit — Wired​.it

    ‘Dur­ing the brief, but very inter­est­ing Q&A ses­sion, Lethem argued that inter­net cul­ture brought the “closet into the open”, that is, it gave ephemera, triv­i­al­i­ties, and every­day activ­i­ties “A new kind of vis­i­bil­ity”. “Peo­ple have always been pro­duc­ing weird stuff and have always been engag­ing in arcane activ­i­ties,” Lethem remarked. “What is really new is the fact the now we can see it. We can see it all. We can quan­tify what we do — or not do — online.” Lethem men­tioned the uncanny abil­ity to track, in real time, “how many books I am not sell­ing on Ama­zon”. “Real­ity has acquired a new level of mea­sur­a­bil­ity”. “The activ­i­ties we per­form in our dig­i­tal age are not nec­es­sar­ily new. What is new is that. We. Can. See. Them. All.”.’

    one-​​measures-​​a-​​circle inter­per­me­ation access local­ism
  • Sex, Oil, and Video­tape | Mother Jones

    “Loom­ing over Saylor’s con­fronta­tion with Bolen­baugh was the EPA’s Sep­tem­ber 27 cleanup dead­line, and it appears that Enbridge and its con­trac­tors were feel­ing the pres­sure as it drew near. In early Sep­tem­ber, after the Michi­gan Mes­sen­ger pub­lished its exposé on the use of undoc­u­mented work­ers by Hall­mark Indus­trial, another group of work­ers employed by a dif­fer­ent Enbridge con­trac­tor came for­ward with detailed sto­ries of how they had been instructed to con­ceal oil at the same site. Work­ers would land on an island, they said, remove all veg­e­ta­tion, and then lay out absorbent pom-​​poms, all per EPA reg­u­la­tions. But once the top layer of oil was absorbed, they were instructed to rake dirt over the area to make it appear as though it had been dug out. One worker described his super­vi­sor show­ing him the process step-​​by-​​step, con­clud­ing with sprin­kling a thin layer of dirt on top. “He said, ‘There, now they can’t see it. It is clean,’” the worker told the Mes­sen­ger. Another worker described being told to cover pock­ets of oil with leaves and sticks. As a last step, such areas were cor­doned off with cau­tion tape.”

    oil­spill Kala­ma­zoo local whistle­blower
  • [1204.4200] Dis­crete Dynam­i­cal Genetic Pro­gram­ming in XCS

    “A num­ber of rep­re­sen­ta­tion schemes have been pre­sented for use within Learn­ing Clas­si­fier Sys­tems, rang­ing from binary encod­ings to neural net­works. This paper presents results from an inves­ti­ga­tion into using a dis­crete dynam­i­cal sys­tem rep­re­sen­ta­tion within the XCS Learn­ing Clas­si­fier Sys­tem. In par­tic­u­lar, asyn­chro­nous ran­dom Boolean net­works are used to rep­re­sent the tra­di­tional condition-​​action pro­duc­tion sys­tem rules. It is shown pos­si­ble to use self-​​adaptive, open-​​ended evo­lu­tion to design an ensem­ble of such dis­crete dynam­i­cal sys­tems within XCS to solve a num­ber of well-​​known test problems.”

    genetic-​​programming learning-​​classifier-​​systems representation-​​theory design-​​patterns boolean-​​networks nudge-​​targets nice
  • Why Is Darwin’s Tan­gled Bank Tan­gled? : 13.7: Cos­mos And Cul­ture : NPR

    Sad to hear him still phras­ing this sim­ple truth so obscurely: Not “Because, on the scale of mol­e­c­u­lar bind­ing site recog­ni­tion, say a few tens of angstroms in length, height and width and sev­eral other fea­tures such as polar­ity, van-​​der-​​Waal forces, and so on, there are far fewer effec­tively dif­fer­ent mol­e­c­u­lar shapes than there are kinds of mol­e­cules.“ … but “Because there are fewer sto­ries than there are facts.”

    oh-​​stu pragmatism-it-ain’t philosophy-​​of-​​science
  • Math Notes | Futil­ity Closet

    So for finite sequences of dig­its, which sequences are such that the most right-​​truncated sub­strings are prime? Which are such that the most right-​​repeating exten­sions are prime?

    nudge-​​targets number-​​theory indirect-​​link
  • Home — Scal­able and Mod­u­lar Archi­tec­ture for CSS

    “I’ve been ana­lyz­ing my process (and the process of those around me) and fig­ur­ing out how best to struc­ture code for projects on a larger scale. What I’ve found is a process that works equally well for sites small and large. Learn how to struc­ture your CSS to allow for flex­i­bil­ity and main­tain­abil­ity as your project and your team grows.”

    css tuto­r­ial best-​​practices graphic-​​design via-​​trek
  • [1204.3678] Crowd Mem­ory: Learn­ing in the Collective

    “Crowd algo­rithms often assume work­ers are inex­pe­ri­enced and thus fail to adapt as work­ers in the crowd learn a task. These assump­tions fun­da­men­tally limit the types of tasks that sys­tems based on such algo­rithms can han­dle. This paper explores how the crowd learns and remem­bers over time in the con­text of human com­pu­ta­tion, and how more real­is­tic assump­tions of worker expe­ri­ence may be used when design­ing new sys­tems. We first demon­strate that the crowd can recall infor­ma­tion over time and dis­cuss pos­si­ble impli­ca­tions of crowd mem­ory in the design of crowd algo­rithms. We then explore crowd learn­ing dur­ing a con­tin­u­ous con­trol task. Recent sys­tems are able to dis­guise dynamic groups of work­ers as crowd agents to sup­port con­tin­u­ous tasks, but have not yet con­sid­ered how such agents are able to learn over time. We show, using a real-​​time gam­ing set­ting, that crowd agents can learn over time, and ‘remem­ber’ by pass­ing strate­gies from one gen­er­a­tion of work­ers to the next, despite high turnover rates in the work­ers com­pris­ing them. We con­clude with a dis­cus­sion of future research direc­tions for crowd mem­ory and learning.”

    crowd­sourc­ing learn­ing agent-​​based collective-​​intelligence mem­ory nudge-​​targets
  • [0911.1582] Manip­u­lat­ing Tour­na­ments in Cup and Round Robin Competitions

    “In sports com­pe­ti­tions, teams can manip­u­late the result by, for instance, throw­ing games. We show that we can decide how to manip­u­late round robin and cup com­pe­ti­tions, two of the most pop­u­lar types of sport­ing com­pe­ti­tions in poly­no­mial time. In addi­tion, we show that find­ing the min­i­mal num­ber of games that need to be thrown to manip­u­late the result can also be deter­mined in poly­no­mial time. Finally, we show that there are sev­eral dif­fer­ent vari­a­tions of stan­dard cup com­pe­ti­tions where manip­u­la­tion remains polynomial.”

    algo­rithms eco­nom­ics game-​​theory nudge-​​targets
  • Intro­duc­ing the Jour­nal of Dig­i­tal Human­i­ties — ProfHacker — The Chron­i­cle of Higher Education

    “If the con­tents of the inau­gural issue—which range from an essay argu­ing that human­ists need to under­stand and inter­pret quan­ti­ta­tive data to a review of the Word­Seer text analy­sis tool—fall out­side your usual schol­arly domain, then cer­tainly the journal’s edi­to­r­ial and pub­lish­ing appa­ra­tus will piqué your interest. As Dan Cohen explained in a sep­a­rate blog post, the jour­nal oper­ates under the model of catch­ing the good—of find­ing sub­stan­tive and valu­able dig­i­tal human­i­ties work “in what­ever for­mat, and wher­ever, it exists.” Blogs, pod­casts, Twit­ter con­ver­sa­tions, slideshows, and so on, these are all venues in which sig­nif­i­cant and, though I hate to use such an ungainly word, impact­ful work is being done. The reg­u­lar and guest edi­tors “catch” this work, and then pro­vide lay­ers of eval­u­a­tion and review before it appears in JDH.”

    digital-​​humanities jour­nal to-​​read two-​​cultures-​​only-​​one-​​of-​​which-​​can-​​write
  • [1005.4159] The Com­plex­ity of Manip­u­lat­ing $k$-Approval Elections

    “An impor­tant prob­lem in com­pu­ta­tional social choice the­ory is the com­plex­ity of unde­sir­able behav­ior among agents, such as con­trol, manip­u­la­tion, and bribery in elec­tion sys­tems. These kinds of vot­ing strate­gies are often tempt­ing at the indi­vid­ual level but dis­as­trous for the agents as a whole. Cre­at­ing elec­tion sys­tems where the deter­mi­na­tion of such strate­gies is dif­fi­cult is thus an impor­tant goal. …”

    vot­ing game-​​theory design-​​patterns mechanism-​​design nudge-​​targets
  • [0903.1147] Tetravex is NP-​​complete

    “Tetravex is a widely played one per­son com­puter game in which you are given $n^2$ unit tiles, each edge of which is labelled with a num­ber. The objec­tive is to place each tile within a $n$ by $n$ square such that all neigh­bour­ing edges are labelled with an iden­ti­cal num­ber. Unfor­tu­nately, play­ing Tetravex is com­pu­ta­tion­ally hard. More pre­cisely, we prove that decid­ing if there is a tiling of the Tetravex board is NP-​​complete. Decid­ing where to place the tiles is there­fore NP-​​hard. This may help to explain why Tetravex is a good puz­zle. This result com­pli­ments a num­ber of sim­i­lar results for one per­son games involv­ing tiling. For exam­ple, NP-​​completeness results have been shown for: the offline ver­sion of Tetris, KPlumber (which involves rotat­ing tiles con­tain­ing draw­ings of pipes to make a con­nected net­work), and short­est slid­ing puz­zle prob­lems. It raises a num­ber of open ques­tions. For exam­ple, is the infi­nite ver­sion Turing-​​complete? How do we gen­er­ate Tetravex prob­lems which are truly puz­zling as ran­dom NP-​​complete prob­lems are often sur­pris­ing easy to solve? Can we observe phase tran­si­tion behav­iour? What about the com­plex­ity of the prob­lem when it is guar­an­teed to have an unique solu­tion? How do we gen­er­ate puz­zles with unique solutions?”

    mathematical-​​recreations computational-​​complexity algo­rithms nudge-​​targets
  • [1204.4286] Fair Allo­ca­tion With­out Trade

    “We con­sider the age-​​old prob­lem of allo­cat­ing items among dif­fer­ent agents in a way that is effi­cient and fair. Two papers, by Dolev et al. and Ghodsi et al., have recently stud­ied this prob­lem in the con­text of com­puter sys­tems. Both papers had sim­i­lar mod­els for agent pref­er­ences, but advo­cated dif­fer­ent notions of fair­ness. We for­mal­ize both fair­ness notions in eco­nomic terms, extend­ing them to apply to a larger fam­ily of util­i­ties. Not­ing that in set­tings with such util­i­ties effi­ciency is eas­ily achieved in mul­ti­ple ways, we study notions of fair­ness as cri­te­ria for choos­ing between dif­fer­ent effi­cient allo­ca­tions. Our tech­ni­cal results are algo­rithms for find­ing fair allo­ca­tions cor­re­spond­ing to two fair­ness notions: Regard­ing the notion sug­gested by Ghodsi et al., we present a polynomial-​​time algo­rithm that com­putes an allo­ca­tion for a gen­eral class of fair­ness notions, in which their notion is included. For the other, sug­gested by Dolev et al., we show that a com­pet­i­tive mar­ket equi­lib­rium achieves the desired notion of fair­ness, thereby obtain­ing a polynomial-​​time algo­rithm that com­putes such a fair allo­ca­tion and solv­ing the main open prob­lem raised by Dolev et al.”

    eco­nom­ics game-​​theory fair­ness algo­rithms phi­los­o­phy design-​​patterns
  • Why is Esti­mat­ing so Hard? | 8th Light

    “It turns out that we don’t know the pro­ce­dure. We haven’t got any clue to just how dif­fi­cult the pro­ce­dure is. We aren’t com­put­ers. We don’t fol­low pro­ce­dures. And so com­par­ing the com­plex­ity of the man­ual task, to the com­plex­ity of the pro­ce­dure is invalid. This is one of the rea­sons that esti­mates are so hard, and why we get them wrong so often. We look at a task that seems easy and esti­mate it on that basis, only to find that writ­ing down the pro­ce­dure is actu­ally quite intri­cate. We blow the esti­mate because we esti­mate the wrong thing.”

    esti­ma­tion agile-​​practices philosophy-​​of-​​engineering man­age­ment self-​​definition plan­ning
  • [1204.4374] Higher Order City Voronoi Diagrams

    “We inves­ti­gate higher-​​order Voronoi dia­grams in the city met­ric. This met­ric is induced by quick­est paths in the L1 met­ric in the pres­ence of an accel­er­at­ing trans­porta­tion net­work of axis-​​parallel line segments. …”

    computational-​​geometry algo­rithms voronoi-​​diagrams diver­sity network-​​theory nudge-​​targets
  • Topic mod­el­ing made just sim­ple enough. | The Stone and the Shell

    “Com­puter sci­en­tists make LDA seem com­pli­cated because they care about prov­ing that their algo­rithms work. And the proof is indeed brain-​​squashingly hard. But the prac­tice of topic mod­el­ing makes good sense on its own, with­out proof, and does not require you to spend even a sec­ond think­ing about “Dirich­let dis­tri­b­u­tions.” When the math is approached in a prac­ti­cal way, I think human­ists will find it easy, intu­itive, and empow­er­ing. This post focuses on LDA as short­hand for a broader fam­ily of “prob­a­bilis­tic” tech­niques. I’m going to ask how they work, what they’re for, and what their lim­its are.”

    text-​​processing clas­si­fi­ca­tion algo­rithms lovely two-​​cultures-​​only-​​one-​​of-​​which-​​can-​​write
  • Math­e­mati­cians are Giraffe Hunters by Barry Mazur | berfrois

    “No won­der life (i.e., the thing that my once 10-​​year old niece referred to as “the thing that isn’t fair”) comes to us as a fil­i­gree of ash sto­ries. Walk­ing down the street past a cou­ple in con­ver­sa­tion, an over­heard mor­pheme, a mere glance at a wrongly but­toned rain­coat, sparks a nar­ra­tive in our imag­i­na­tion. Ask any ques­tion begin­ning with “why?” and the answer will surely be a story, or it will be embed­ded in a story. Or, at the very least, it will offer a tempt­ing thread for some story that you your­self will hold onto, embell­ish even, as you try to absorb the answer. We inter­po­late between such frag­ments. This is, for many of us, sim­ply the way we think. What about the “why ques­tions” in sci­ence, in logic, in math­e­mat­ics? We should acknowl­edge how they are often “what ques­tions” or “how ques­tions” in dis­guise. Or how they slide down into such ques­tions, as the ever-​​elusive, ever-​​illusory quest for an X that actu­ally causes a Y dis­solves. Some of the more sat­is­fy­ing answers to sci­en­tific “why” ques­tions involves deft rephras­ing. “Why is the sky blue?” is replaced by the ques­tion “what is the func­tion that describes scat­ter­ing ampli­tude as depen­dent on wave-​​length”?”

    math­e­mat­ics philosophy-​​of-​​mathematics sto­ry­telling prag­ma­tism theory-​​and-​​practice-​​sitting-​​in-​​a-​​tree what-​​is-​​it-​​good-​​for-​​hunh

Items of some interest:

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

  • Nicholas Rombes: Punk | berfrois

    “Most iron­i­cally, being based in the hope­lessly lost cul­tural void of Ann Arbor, a noto­ri­ous mecca for the last sur­viv­ing rem­nants of the pseudo-​​intellectual street peo­ple move­ment that said much and accom­plished little…”

    punk history-​​is-​​a-​​feature-​​not-​​a-​​bug cultural-​​dynamics ha-​​ha-​​only-​​semiserious
  • [1112.5309] POWERPLAY: Train­ing an Increas­ingly Gen­eral Prob­lem Solver by Con­tin­u­ally Search­ing for the Sim­plest Still Unsolv­able Problem

    An amus­ing col­lec­tion of what seem to be half-​​remembered ideas gleaned from his visit to the GPTP work­shop in Ann Arbor two years ago, pre­sented as his own inven­tions and with­out cita­tion or men­tion of the dozen peo­ple who actu­ally do this work. His keynote, as I remem­ber it, essen­tially revolved around him point­ing out how influ­en­tial his work should have been all along, if only we had both­ered to cite him as we should have done, because he thought up the core con­cepts of genetic pro­gram­ming well before any of us claimed we had. This is pretty much a camel’s-back straw for me. If there is a bet­ter argu­ment for com­pletely boy­cotting the cita­tion sys­tem and rely­ing on per­sonal asso­ci­a­tion and named schools rather than pub­li­ca­tion, I have not yet encoun­tered it. So remem­ber poor oppressed grad­u­ate and post­doc kids: when I cite your work by sim­ply nam­ing you per­son­ally, and not your advi­sor or your insti­tu­tion, and not even your pub­li­ca­tion or jour­nal but merely YOU PERSONALLY, it’s because you per­son­ally deserve the credit, not any of those other leeches. Got that?

    now-​​this-​​really-​​pisses-​​me-​​off-​​to-​​no-​​end
  • [1203.0856] Online Dis­crim­i­na­tive Dic­tio­nary Learn­ing for Image Clas­si­fi­ca­tion Based on Block-​​Coordinate Descent Method

    “Pre­vi­ous researches have demon­strated that the frame­work of dic­tio­nary learn­ing with sparse cod­ing, in which sig­nals are decom­posed as lin­ear com­bi­na­tions of a few atoms of a learned dic­tio­nary, is well adept to recon­struc­tion issues. This frame­work has also been used for dis­crim­i­na­tion tasks such as image clas­si­fi­ca­tion. To achieve bet­ter per­for­mances of clas­si­fi­ca­tion, experts develop sev­eral meth­ods to learn a dis­crim­i­na­tive dic­tio­nary in a super­vised man­ner. How­ever, another issue is that when the data become extremely large in scale, these meth­ods will be no longer effec­tive as they are all batch-​​oriented approaches. For this rea­son, we pro­pose a novel online algo­rithm for dis­crim­i­na­tive dic­tio­nary learn­ing, dubbed textbf{ODDL} in this paper. First, we intro­duce a lin­ear clas­si­fier into the con­ven­tional dic­tio­nary learn­ing for­mu­la­tion and derive a dis­crim­i­na­tive dic­tio­nary learn­ing prob­lem. Then, we exploit an online algo­rithm to solve the derived prob­lem. Unlike the most exist­ing approaches which update dic­tio­nary and clas­si­fier alter­nately via iter­a­tively solv­ing sub-​​problems, our approach directly explores them jointly. Mean­while, it can largely shorten the run­time for train­ing and is also par­tic­u­larly suit­able for large-​​scale clas­si­fi­ca­tion issues. To eval­u­ate the per­for­mance of the pro­posed ODDL approach in image recog­ni­tion, we con­duct some exper­i­ments on three well-​​known bench­marks, and the exper­i­men­tal results demon­strate ODDL is fairly promis­ing for image clas­si­fi­ca­tion tasks.”

    image-​​analysis image-​​segmentation algo­rithms nudge-​​targets
  • [1203.3271] The ther­mo­dy­nam­ics of prediction

    “A sys­tem respond­ing to a sto­chas­tic dri­ving sig­nal can be inter­preted as com­put­ing, by means of its dynam­ics, an (implicit) model of the envi­ron­men­tal vari­ables. The system’s state retains infor­ma­tion about past envi­ron­men­tal fluc­tu­a­tions, and a frac­tion of this infor­ma­tion is pre­dic­tive of future ones. The remain­ing non­pre­dic­tive infor­ma­tion reflects model com­plex­ity that does not improve pre­dic­tive power, and rep­re­sents the inef­fec­tive­ness of the model. We expose the fun­da­men­tal equiv­a­lence between this model inef­fi­ciency and ther­mo­dy­namic inef­fi­ciency, mea­sured by the energy dis­si­pated dur­ing the inter­ac­tion between sys­tem and envi­ron­ment. Our results hold arbi­trar­ily far from ther­mo­dy­namic equi­lib­rium and are applic­a­ble to a wide range of sys­tems, includ­ing bio­mol­e­c­u­lar machines. They high­light a pro­found con­nec­tion between the effec­tive use of infor­ma­tion and effi­cient ther­mo­dy­namic oper­a­tion: any sys­tem con­structed to keep mem­ory about its envi­ron­ment and to oper­ate ener­get­i­cally effi­ciently has to be predictive.”

    mod­el­ing philosophy-​​of-​​science information-​​theory physics ther­mo­dy­nam­ics talking-​​about-​​a-​​model-​​is-​​a-​​model pragmatism-it-ain’t
  • [1203.3434] On the Impact of Infor­ma­tion Tech­nolo­gies on Soci­ety: an His­tor­i­cal Per­spec­tive through the Game of Chess

    “The game of chess as always been viewed as an iconic rep­re­sen­ta­tion of intel­lec­tual prowess. Since the very begin­ning of com­puter sci­ence, the chal­lenge of being able to pro­gram a com­puter capa­ble of play­ing chess and beat­ing humans has been alive and used both as a mark to mea­sure hardware/​software pro­gresses and as an ongo­ing pro­gram­ming chal­lenge lead­ing to numer­ous dis­cov­er­ies. In the early days of com­puter sci­ence it was a topic for spe­cial­ists. But as com­put­ers were democ­ra­tized, and the strength of chess engines began to increase, chess play­ers started to appro­pri­ate to them­selves these new tools. We show how these inter­ac­tions between the world of chess and infor­ma­tion tech­nolo­gies have been her­ald of broader social impacts of infor­ma­tion tech­nolo­gies. The game of chess, and more broadly the world of chess (chess play­ers, lit­er­a­ture, com­puter soft­wares and web­sites ded­i­cated to chess, etc.), turns out to be a sur­pris­ingly and par­tic­u­larly sharp indi­ca­tor of the changes induced in our every­day life by the infor­ma­tion tech­nolo­gies. More­over, in the same way that chess is a mod­eliza­tion of war that cap­tures the raw fea­tures of strate­gic think­ing, chess world can be seen as small soci­ety mak­ing the study of the infor­ma­tion tech­nolo­gies impact eas­ier to ana­lyze and to grasp.”

    touch­stones his­tory algo­rithms history-​​of-​​science computer-​​science
  • Share Books | berfrois

    “Libraries are a recog­ni­tion that schol­ar­ship and cul­ture are more than the busi­ness of cre­at­ing and con­sum­ing. They are a human con­ver­sa­tion, and libraries pro­vide com­mon ground where that con­ver­sa­tion can take place and be remem­bered. By tak­ing aim at the right for the pub­lic to main­tain this con­ver­sa­tion and its mem­ory, pub­lish­ers have shown us what we have to lose. It’s time we resisted the out­sourc­ing of our com­mon her­itage by occu­py­ing the library.”

    Occupy libraries intellectual-​​property open-​​access public-​​policy activism
  • [1112.3307] Poly­tope Codes Against Adver­saries in Networks

    “Net­work cod­ing is stud­ied when an adver­sary con­trols a sub­set of nodes in the net­work of lim­ited quan­tity but unknown loca­tion. This prob­lem is shown to be more dif­fi­cult than when the adver­sary con­trols a given num­ber of edges in the net­work, in that lin­ear codes are insuf­fi­cient. To solve the node prob­lem, the class of Poly­tope Codes is intro­duced. Poly­tope Codes are con­stant com­po­si­tion codes oper­at­ing over bounded poly­topes in inte­ger vec­tor fields. The poly­tope struc­ture cre­ates addi­tional com­plex­ity, but it induces prop­er­ties on mar­ginal dis­tri­b­u­tions of code vec­tors so that validi­ties of code­words can be checked by inter­nal nodes of the net­work. It is shown that Poly­tope Codes achieve a cut-​​set bound for a class of pla­nar net­works. It is also shown that this cut-​​set bound is not always tight, and a tighter bound is given for an exam­ple network.”

    cryp­tog­ra­phy pri­vacy algo­rithms nudge-​​targets network-​​theory com­mu­ni­ca­tion
  • [1203.3353] Solv­ing Struc­ture with Sparse, Randomly-​​Oriented X-​​ray Data

    “Single-​​particle imag­ing exper­i­ments of bio­mol­e­cules at x-​​ray free-​​electron lasers (XFELs) require pro­cess­ing of hun­dreds of thou­sands (or more) of images that con­tain very few x-​​rays. Each low-​​flux image of the dif­frac­tion pat­tern is pro­duced by a sin­gle, ran­domly ori­ented par­ti­cle, such as a pro­tein. We demon­strate the fea­si­bil­ity of col­lect­ing data at these extremes, aver­ag­ing only 2.5 pho­tons per frame, where it seems doubt­ful there could be infor­ma­tion about the state of rota­tion, let alone the image con­trast. This is accom­plished with an expec­ta­tion max­i­miza­tion algo­rithm that processes the low-​​flux data in aggre­gate, and with­out any prior knowl­edge of the object or its ori­en­ta­tion. The ver­sa­til­ity of the method promises, more gen­er­ally, to rede­fine what mea­sure­ment sce­nar­ios can pro­vide use­ful sig­nal in the high-​​noise regime.”

    structural-​​biology image-​​analysis crys­tal­log­ra­phy algo­rithms inverse-​​problems nudge-​​targets sta­tis­tics
  • [1203.3203] An effi­cient algo­rithm for gen­er­at­ing AoA networks

    “The activ­i­ties, in project sched­ul­ing, can be rep­re­sented graph­i­cally in two dif­fer­ent ways, by either assign­ing the activ­i­ties to the nodes ‘AoN’ directed acyclic graph (dag) or to the arcs ‘AoA dag’. In this paper, a new algo­rithm is pro­posed for gen­er­at­ing, for a given project sched­ul­ing prob­lem, an Activity-​​on-​​Arc dag start­ing from the Activity-​​on-​​Node dag using the con­cepts of line graphs of graphs.”

    sched­ul­ing operations-​​research algo­rithms graph-​​theory
  • [1203.3341] A Com­par­i­son of Multi-​​Parametric Pro­gram­ming, Mixed-​​Integer Pro­gram­ming, Gra­di­ent Descent Based, and the Embed­ding Approach on Four Pub­lished Hybrid Opti­mal Con­trol Examples

    “…Com­mon mis­con­cep­tions regard­ing the embed­ding approach are addressed includ­ing whether or not it results in an aver­age value con­trol model (no), is nec­es­sary to “tweak” the algo­rithm to get bang-​​bang solu­tions (no), requires infi­nite switch­ing (no), has real-​​time capa­bil­ity (yes), or reduc­tion to a clas­si­cal non­lin­ear opti­miza­tion prob­lem (a desir­able yes).”

    control-​​theory operations-​​research algo­rithms numerical-​​methods philosophy-​​of-​​engineering design-​​patterns nudge-​​targets
  • [1203.3270] Extrac­tion of Facial Fea­ture Points Using Cumu­la­tive Histogram

    “This paper pro­poses a novel adap­tive algo­rithm to extract facial fea­ture points auto­mat­i­cally such as eye­brows cor­ners, eyes cor­ners, nos­trils, nose tip, and mouth cor­ners in frontal view faces, which is based on cumu­la­tive his­togram approach by vary­ing dif­fer­ent thresh­old val­ues. At first, the method adopts the Viola-​​Jones face detec­tor to detect the loca­tion of face and also crops the face region in an image. From the con­cept of the human face struc­ture, the six rel­e­vant regions such as right eye­brow, left eye­brow, right eye, left eye, nose, and mouth areas are cropped in a face image. Then the his­togram of each cropped rel­e­vant region is com­puted and its cumu­la­tive his­togram value is employed by vary­ing dif­fer­ent thresh­old val­ues to cre­ate a new fil­ter­ing image in an adap­tive way. The con­nected com­po­nent of inter­ested area for each rel­e­vant fil­ter­ing image is indi­cated our respec­tive fea­ture region. A sim­ple lin­ear search algo­rithm for eye­brows, eyes and mouth fil­ter­ing images and con­tour algo­rithm for nose fil­ter­ing image are applied to extract our desired cor­ner points auto­mat­i­cally. The method was tested on a large BioID frontal face data­base in dif­fer­ent illu­mi­na­tions, expres­sions and light­ing con­di­tions and the exper­i­men­tal results have achieved aver­age suc­cess rates of 95.27%.”

    image-​​segmentation image-​​analysis face-​​recognition algo­rithms nudge-​​targets
  • [1203.3284] Effi­cient Enu­mer­a­tion of the Directed Binary Per­fect Phy­lo­ge­nies from Incom­plete Data

    “We study a character-​​based phy­logeny recon­struc­tion prob­lem when an incom­plete set of data is given. More specif­i­cally, we con­sider the sit­u­a­tion under the directed per­fect phy­logeny assump­tion with binary char­ac­ters in which for some species the states of some char­ac­ters are miss­ing. Our main object is to give an effi­cient algo­rithm to enu­mer­ate (or list) all per­fect phy­lo­ge­nies that can be obtained when the miss­ing entries are com­pleted. While a sim­ple branch-​​and-​​bound algo­rithm (B&B) shows a the­o­ret­i­cally good per­for­mance, we pro­pose another approach based on a zero-​​suppressed binary deci­sion dia­gram (ZDD). Exper­i­men­tal results on ran­domly gen­er­ated data exhibit that the ZDD approach out­per­forms B&B. We also prove that count­ing the num­ber of phy­lo­ge­netic trees con­sis­tent with a given data is #P-​​complete, thus pro­vid­ing an evi­dence that an effi­cient ran­dom sam­pling seems hard.”

    phy­lo­ge­net­ics inverse-​​problems genet­ics algo­rithms sta­tis­tics nudge-​​targets
  • [1203.0879] Design­ing and using prior knowl­edge for phase retrieval

    “In this work we develop an algo­rithm for sig­nal recon­struc­tion from the mag­ni­tude of its Fourier trans­form in a sit­u­a­tion where some (non-​​zero) parts of the sought sig­nal are known. Although our method does not assume that the known part com­prises the bound­ary of the sought sig­nal, this is often the case in microscopy: a spec­i­men is placed inside a known mask, which can be thought of as a known light source that sur­rounds the unknown sig­nal. There­fore, in the past, sev­eral algo­rithms were sug­gested that solve the phase retrieval prob­lem assum­ing known bound­ary val­ues. Unlike our method, these meth­ods do rely on the fact that the known part is on the bound­ary. Besides the recon­struc­tion method we give an expla­na­tion of the phe­nom­ena observed in pre­vi­ous work: the recon­struc­tion is much faster when there is more energy con­cen­trated in the known part. Quite sur­pris­ingly, this can be explained using our pre­vi­ous results on phase retrieval with approx­i­mately known Fourier phase.”

    image-​​analysis image-​​processing learn­ing inverse-​​problems algo­rithms nudge-​​targets
  • [1203.3415] A New Approach to Count Pat­tern Motifs Using Com­bi­na­to­r­ial Techniches

    “We pro­posed two new exact algo­rithms to detect net­work motifs of size 3 and 4. Con­sid­er­ing that motifs need to count the iso­mor­phic pat­terns in the orig­i­nal graph $G(V,E)$ and in a set of ran­dom­ized graphs, the fol­low­ing com­plex­i­ties con­cern about count iso­mor­phic pat­terns in a sin­gle graph. Let $m=|E|$ and let $a(G)$ be the arboric­ity of $G$. Assume $|E|geq|V|$. We describe a $O(a(G)m)$ time com­plex­ity algo­rithm to count iso­mor­phic pat­terns of size 3. The com­plex­ity is a $O({msqrt{m}})$ in the worst graph. The sec­ond algo­rithm is a $O(m^2)$ com­plex­ity algo­rithm to count iso­mor­phic pat­terns of size 4. The final result was expres­sive faster when com­pared with other imple­mented algorithms.”

    network-​​theory graph-​​theory algo­rithms 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:

  • [1110.1462] Dynamic Clus­ter­ing of His­togram Data Based on Adap­tive Squared Wasser­stein Distances

    “…To clus­ter sets of his­togram data, we pro­pose to use Dynamic Clus­ter­ing Algo­rithm, (based on adap­tive squared Wasser­stein dis­tances) that is a k-​​means-​​like algo­rithm for clus­ter­ing a set of indi­vid­u­als into K classes that are apri­ori fixed. The main aim of this research is to pro­vide a tool for clus­ter­ing his­tograms, empha­siz­ing the dif­fer­ent con­tri­bu­tions of the his­togram vari­ables, and their com­po­nents, to the def­i­n­i­tion of the clus­ters. We demon­strate that this can be achieved using adap­tive dis­tances. Two kind of adap­tive dis­tances are con­sid­ered: the first takes into account the vari­abil­ity of each com­po­nent of each descrip­tor for the whole set of indi­vid­u­als; the sec­ond takes into account the vari­abil­ity of each com­po­nent of each descrip­tor in each clus­ter. We fur­nish inter­pre­ta­tive tools of the obtained par­ti­tion based on an exten­sion of the clas­si­cal mea­sures (indexes) to the use of adap­tive dis­tances in the clus­ter­ing cri­te­rion func­tion. Appli­ca­tions on syn­thetic and real-​​world data cor­rob­o­rate the pro­posed procedure.”

    clas­si­fi­ca­tion sta­tis­tics his­tograms met­rics clus­ter­ing
  • [1110.1412] Quan­ti­fy­ing loopy net­work architectures

    “Biol­ogy presents many exam­ples of pla­nar dis­tri­b­u­tion and struc­tural net­works hav­ing dense sets of closed loops. An arche­type of this form of net­work orga­ni­za­tion is the vas­cu­la­ture of dicotyle­do­nous leaves, which show­cases a hierarchically-​​nested archi­tec­ture con­tain­ing closed loops at many dif­fer­ent lev­els. Although a num­ber of meth­ods have been pro­posed to mea­sure aspects of the struc­ture of such net­works, a robust met­ric to quan­tify their hier­ar­chi­cal orga­ni­za­tion is still lack­ing. We present an algo­rith­mic frame­work, the hier­ar­chi­cal loop decom­po­si­tion, that allows map­ping loopy net­works to binary trees, pre­serv­ing in the con­nec­tiv­ity of the trees the archi­tec­ture of the orig­i­nal graph. We apply this frame­work to inves­ti­gate com­puter gen­er­ated graphs, such as arti­fi­cial mod­els and opti­mal dis­tri­b­u­tion net­works, as well as nat­ural graphs extracted from dig­i­tized images of dicotyle­do­nous leaves and vas­cu­la­ture of rat cere­bral neo­cor­tex. We cal­cu­late var­i­ous met­rics based on the Asym­me­try, the cumu­la­tive size dis­tri­b­u­tion and the Strahler bifur­ca­tion ratios of the cor­re­spond­ing trees and dis­cuss the rela­tion­ship of these quan­ti­ties to the archi­tec­tural orga­ni­za­tion of the orig­i­nal graphs. This algo­rith­mic frame­work decou­ples the geo­met­ric infor­ma­tion (exact loca­tion of edges and nodes) from the met­ric topol­ogy (con­nec­tiv­ity and edge weight) and it ulti­mately allows us to per­form a quan­ti­ta­tive sta­tis­ti­cal com­par­i­son between pre­dic­tions of the­o­ret­i­cal mod­els and nat­u­rally occur­ring loopy graphs.”

    com­plex­ol­ogy bio­physics network-​​theory met­rics
  • [1110.1393] High-​​Precision Tun­ing of State for Mem­ris­tive Devices by Adapt­able Variation-​​Tolerant Algorithm

    “Using mem­ris­tive prop­er­ties com­mon for the tita­nium diox­ide thin film devices, we designed a sim­ple write algo­rithm to tune device con­duc­tance at a spe­cific bias point to 1% rel­a­tive accu­racy (which is roughly equiv­a­lent to 7-​​bit pre­ci­sion) within its dynamic range even in the pres­ence of large vari­a­tions in switch­ing behav­ior. The high pre­ci­sion state is non­volatile and the results are likely to be sus­tained for nanoscale mem­ris­tive devices because of the inher­ent fil­a­men­tary nature of the resis­tive switch­ing. The pro­posed func­tion­al­ity of mem­ris­tive devices is espe­cially attrac­tive for ana­log com­put­ing with low pre­ci­sion data. As one rep­re­sen­ta­tive exam­ple we demon­strate hybrid cir­cuitry con­sist­ing of CMOS sum­ming ampli­fier and two mem­ris­tive devices to per­form ana­log mul­ti­ply and accu­mu­late com­pu­ta­tion, which is a typ­i­cal bot­tle­neck oper­a­tion in infor­ma­tion processing.”

    mem­ris­tors engineering-​​design sim­u­la­tion control-​​systems nudge-​​targets
  • [1110.1521] Nodal domains of a non-​​separable prob­lem — the right angled isosce­les triangle

    “Our result may be gen­er­al­ized to other domains where sim­i­lar algo­rithms may apply. Our algo­rithm is based on the fact that the eigen­func­tions are pre­sented as a lin­ear com­bi­na­tion of sim­ple plane waves. It is there­fore tempt­ing to try and gen­er­al­ize it for other drums with sim­i­lar prop­erty. The equi­lat­eral tri­an­gle is an imme­di­ate can­di­date (see [29] and ref­er­ences within). A fur­ther, and quite sur­pris­ing, result is the recur­sive for­mula for the num­ber of nodal loops. To our knowl­edge this is the first known exact for­mula for the nodal count of a non-​​separable pla­nar man­i­fold (for cer­tain eigen­func­tions of tori exact for­mu­las have been given in [22]). The for­mula was found by direct inspec­tion of large tables and has been ver­i­fied for a large bulk of data com­pu­ta­tion­ally. An obvi­ous chal­lenge is to prove this for­mula. In par­tic­u­lar, the recur­sive part of the for­mula resem­bles the famous Euclid algo­rithm for the great­est com­mon divi­sor. A fur­ther inves­ti­ga­tion of the men­tioned for­mula might there­fore expose some new num­ber the­o­ret­i­cal prop­er­ties of the nodal count.”

    physics algo­rithms analytical-​​results open-​​questions geom­e­try acoustics exact-​​form nudge-​​targets
  • [1110.1485] A Face Recog­ni­tion Scheme using Wavelet Based Dom­i­nant Features

    “In this paper, a multi-​​resolution fea­ture extrac­tion algo­rithm for face recog­ni­tion is pro­posed based on two-​​dimensional dis­crete wavelet trans­form (2D-​​DWT), which effi­ciently exploits the local spa­tial vari­a­tions in a face image. For the pur­pose of fea­ture extrac­tion, instead of con­sid­er­ing the entire face image, an entropy-​​based local band selec­tion cri­te­rion is devel­oped, which selects high-​​informative hor­i­zon­tal seg­ments from the face image. In order to cap­ture the local spa­tial vari­a­tions within these high­in­for­ma­tive hor­i­zon­tal bands pre­cisely, the hor­i­zon­tal band is seg­mented into sev­eral small spa­tial mod­ules. Dom­i­nant wavelet coef­fi­cients cor­re­spond­ing to each local region resid­ing inside those hor­i­zon­tal bands are selected as fea­tures. In the selec­tion of the dom­i­nant coef­fi­cients, a thresh­old cri­te­rion is pro­posed, which not only dras­ti­cally reduces the fea­ture dimen­sion but also pro­vides high within-​​class com­pact­ness and high between-​​class sep­a­ra­bil­ity. A prin­ci­pal com­po­nent analy­sis is per­formed to fur­ther reduce the dimen­sion­al­ity of the fea­ture space. Exten­sive exper­i­men­ta­tion is car­ried out upon stan­dard face data­bases and a very high degree of recog­ni­tion accu­racy is achieved by the pro­posed method in com­par­i­son to those obtained by some of the exist­ing methods.”

    face-​​recognition algo­rithms image-​​processing wavelets nudge-​​targets
  • [1110.1553] Hier­ar­chi­cal QR fac­tor­iza­tion algo­rithms for multi-​​core clus­ter systems

    “This paper describes a new QR fac­tor­iza­tion algo­rithm which is espe­cially designed for mas­sively par­al­lel plat­forms com­bin­ing par­al­lel dis­trib­uted multi-​​core nodes. These plat­forms make the present and the fore­see­able future of high-​​performance com­put­ing. Our new QR fac­tor­iza­tion algo­rithm falls in the cat­e­gory of the tile algo­rithms which nat­u­rally enables good data local­ity for the sequen­tial ker­nels exe­cuted by the cores (high sequen­tial per­for­mance), low num­ber of mes­sages in a par­al­lel dis­trib­uted set­ting (small latency term), and fine gran­u­lar­ity (high parallelism).”

    parallel-​​computing operations-​​research fac­tor­iza­tion algo­rithms nudge-​​targets meta-​​algorithms
  • [1110.1560] On the Col­or­ing of Grid Wire­less Sen­sor Net­works: the Vector-​​Based Col­or­ing Method

    “Graph col­or­ing is used in wire­less net­works to opti­mize net­work resources: band­width and energy. Nodes access the medium accord­ing to their color. It is the respon­si­bil­ity of the col­or­ing algo­rithm to ensure that inter­fer­ing nodes do not have the same color. In this research report, we focus on wire­less sen­sor net­works with grid topolo­gies. How does a col­or­ing algo­rithm take advan­tage of the reg­u­lar­ity of grid topol­ogy to pro­vide an opti­mal peri­odic col­or­ing, that is a col­or­ing with the min­i­mum num­ber of col­ors? We pro­pose the Vector-​​Based Col­or­ing Method, denoted VCM, a new method that is able to pro­vide an opti­mal peri­odic col­or­ing for any radio trans­mis­sion range and for any h-​​hop col­or­ing, h>=1. This method con­sists in deter­min­ing at which grid nodes a color can be repro­duced with­out cre­at­ing inter­fer­ences between these nodes while min­i­miz­ing the num­ber of col­ors used. We com­pare the num­ber of col­ors pro­vided by VCM with the num­ber of col­ors obtained by a dis­trib­uted col­or­ing algo­rithm with line and col­umn pri­or­ity assign­ments. We also pro­vide bounds on the num­ber of col­ors of opti­mal gen­eral col­or­ings of the infi­nite grid, and show that peri­odic col­or­ings (and thus VCM) are asymp­tot­i­cally opti­mal. Finally, we dis­cuss the applic­a­bil­ity of this method to a real wire­less network.”

    graph-​​theory algo­rithms operations-​​research nudge-​​targets
  • [1110.1580] A Polylogarithmic-​​Competitive Algo­rithm for the k-​​Server Problem

    “We give the first polylogarithmic-​​competitive ran­dom­ized online algo­rithm for the $k$-server prob­lem on an arbi­trary finite met­ric space. In par­tic­u­lar, our algo­rithm achieves a com­pet­i­tive ratio of O(log^3 n log^2 k log log n) for any met­ric space on n points. Our algo­rithm improves upon the deter­min­is­tic (2k-1)-competitive algo­rithm of Kout­sou­pias and Papadim­itriou [J.ACM’95] when­ever n is sub-​​exponential in k.”

    sched­ul­ing operations-​​research algo­rithms nudge-​​targets
  • [1110.1590] PSA: The Packet Sched­ul­ing Algo­rithm for Wire­less Sen­sor Networks

    “The main cause of wasted energy con­sump­tion in wire­less sen­sor net­works is packet col­li­sion. The packet sched­ul­ing algo­rithm is there­fore intro­duced to solve this prob­lem. Some packet sched­ul­ing algo­rithms can also influ­ence and delay the data trans­mit­ting in the real-​​time wire­less sen­sor net­works. This paper presents the packet sched­ul­ing algo­rithm (PSA) in order to reduce the packet con­ges­tion in MAC layer lead­ing to reduce the over­all of packet col­li­sion in the sys­tem The PSA is com­pared with the sim­ple CSMA/​CA and other approaches using net­work topol­ogy bench­marks in math­e­mat­i­cal method. The per­for­mances of our PSA are bet­ter than the stan­dard (CSMA/​CA). The PSA pro­duces bet­ter through­put than other algo­rithms. On other hand, the aver­age delay of PSA is higher than pre­vi­ous works. How­ever, the PSA uti­lizes the chan­nel bet­ter than all algorithms.”

    sensor-​​networks distributed-​​processing sched­ul­ing rout­ing operations-​​research algo­rithms nudge-​​targets
  • [1110.0725] A Sur­vey of Dis­trib­uted Data Aggre­ga­tion Algorithms

    “Dis­trib­uted data aggre­ga­tion has been an active field of research in the last decade, and a huge diverse amount of tech­niques can be found in the lit­er­a­ture. For this rea­sons, this sur­vey intends to be an impor­tant time sav­ing instru­ment, for those that desire to get a quick and com­pre­hen­sive overview of the state of the art on dis­trib­uted data aggre­ga­tion. More­over, by care­fully high­light­ing the strength and lim­i­ta­tions of the more per­ti­nent approaches, this study can pro­vide a use­ful assis­tance to help read­ers choose which tech­nique to apply in spe­cific set­tings. Cur­rently, there is no ideal gen­eral solu­tion to the dis­trib­uted com­pu­ta­tion of an aggre­ga­tion func­tion, all exist­ing tech­niques have its pit­falls (some more than oth­ers). There­fore, more research in this field will be expected in the next few years. In par­tic­u­lar, due to the added value of com­put­ing com­plex aggre­gates, new algo­rithms might arise to esti­mate the sta­tis­ti­cal dis­tri­b­u­tion of val­ues, as the few exist­ing approaches exhibit some lim­i­ta­tions in terms of accu­racy and resource con­sump­tion. Addi­tional research efforts should be made to improve the sup­port to churn, mes­sage loss, and con­tin­u­ous esti­ma­tion of muta­ble input values.”

    sta­tis­tics reviews distributed-​​processing com­mu­ni­ca­tion coor­di­na­tion nudge-​​targets
  • [0911.3482] Com­plex­ity of Net­works (reprise)

    “Net­work or graph struc­tures are ubiq­ui­tous in the study of com­plex sys­tems. Often, we are inter­ested in com­plex­ity trends of these sys­tem as it evolves under some dynamic. An exam­ple might be look­ing at the com­plex­ity of a food web as species enter an ecosys­tem via migra­tion or spe­ci­a­tion, and leave via extinc­tion. In a pre­vi­ous paper, a com­plex­ity mea­sure of net­works was pro­posed based on the {em com­plex­ity is infor­ma­tion con­tent} par­a­digm. To apply this par­a­digm to any object, one must fix two things: a rep­re­sen­ta­tion lan­guage, in which strings of sym­bols from some alpha­bet describe, or stand for the objects being con­sid­ered; and a means of deter­min­ing when two such descrip­tions refer to the same object. With these two things set, the infor­ma­tion con­tent of an object can be com­puted in prin­ci­ple from the num­ber of equiv­a­lent descrip­tions describ­ing a par­tic­u­lar object. The pre­vi­ously pro­posed rep­re­sen­ta­tion lan­guage had the defi­ciency that the fully con­nected and empty net­works were the most com­plex for a given num­ber of nodes. A vari­a­tion of this mea­sure, called zcom­plex­ity, applied a com­pres­sion algo­rithm to the result­ing bit­string rep­re­sen­ta­tion, to solve this prob­lem. Unfor­tu­nately, zcom­plex­ity proved too com­pu­ta­tion­ally expen­sive to be prac­ti­cal. In this paper, I pro­pose a new rep­re­sen­ta­tion lan­guage that encodes the num­ber of links along with the num­ber of nodes and a rep­re­sen­ta­tion of the lin­klist. This, like zcom­plex­ity, exhibits min­i­mal com­plex­ity for fully con­nected and empty net­works, but is as tractable as the orig­i­nal measure.”

    network-​​theory com­plex­ol­ogy complex-​​systems mea­sure­ment per­form structure-​​function-​​relations discrete-​​mathematics
  • [1108.4279] Detec­tion and emergence

    “Two dif­fer­ent con­cep­tions of emer­gence are rec­on­ciled as two instances of the phe­nom­e­non of detec­tion. In the process of com­par­ing these two con­cep­tions, we find that the notions of com­plex­ity and detec­tion allow us to form a uni­fied def­i­n­i­tion of emer­gence that clearly delin­eates the role of the observer.”

    com­plex­ol­ogy emer­gence pragmatism-it-ain’t but-​​soon
  • [1001.4278] Weight Opti­miza­tion for Dis­trib­uted Aver­age Con­sen­sus Algo­rithm in Sym­met­ric, CCS & KCS Star Networks

    “This paper addresses weight opti­miza­tion prob­lem in dis­trib­uted con­sen­sus aver­ag­ing algo­rithm over net­works with sym­met­ric star topol­ogy. We have deter­mined opti­mal weights and con­ver­gence rate of the net­work in terms of its topo­log­i­cal para­me­ters. In addi­tion, two alter­na­tive topolo­gies with more rapid con­ver­gence rates have been intro­duced. The new topolo­gies are Complete-​​Cored Sym­met­ric (CCS) star and K-​​Cored Sym­met­ric (KCS) star topolo­gies. It has been shown that the opti­mal weights for the edges of cen­tral part in sym­met­ric and CCS star con­fig­u­ra­tions are inde­pen­dent of their branches. By sim­u­la­tion opti­mal­ity of obtained weights under quan­ti­za­tion con­straints have been verified.”

    operations-​​research decision-​​making network-​​theory nudge-​​targets
  • [1109.5389] Water dri­ves pep­tide con­for­ma­tional transitions

    “Tran­si­tions between metastable con­for­ma­tions of a dipep­tide are inves­ti­gated using clas­si­cal mol­e­c­u­lar dynam­ics sim­u­la­tion with explicit water mol­e­cules. The dis­tri­b­u­tion of the sur­round­ing water at dif­fer­ent moments before the tran­si­tions and the dynam­i­cal cor­re­la­tions of water with the peptide’s con­fig­u­ra­tional motions indi­cate that water is the main dri­ving force of the con­for­ma­tional changes.”

    molecular-​​design systems-​​biology sim­u­la­tion intracellular-​​dynamics kinda-​​knew-​​this-​​a-​​long-​​time-​​ago bio­chem­istry
  • [1105.1445] Vehic­u­lar traf­fic flow at an inter­sec­tion with the pos­si­bil­ity of turning

    “We have devel­oped a Nagel-​​Schreckenberg cel­lu­lar automata model for describ­ing of vehic­u­lar traf­fic flow at a sin­gle inter­sec­tion. A set of traf­fic lights oper­at­ing in fixed-​​time scheme con­trols the traf­fic flow. Open bound­ary con­di­tion is applied to the streets each of which con­duct a uni-​​directional flow. Streets are single-​​lane and cars can turn upon reach­ing to the inter­sec­tion with pre­scribed prob­a­bil­i­ties. Exten­sive Monte Carlo sim­u­la­tions are car­ried out to find the model flow char­ac­ter­is­tics. In par­tic­u­lar, we inves­ti­gate the flows depen­dence on the sig­nal­i­sa­tion para­me­ters, turn­ing prob­a­bil­i­ties and input rates. It is shown that for each set of para­me­ters, there exist a plateau region inside which the total out­flow from the inter­sec­tion remains almost con­stant. We also com­pute total wait­ing time of vehi­cles per cycle behind red lights for var­i­ous con­trol parameters.”

    cellular-​​automata com­plex­ol­ogy traffic-​​models agent-​​based sim­u­la­tion nudge-​​substrates
  • [1110.1391] A Com­par­i­son of Dif­fer­ent Machine Translit­er­a­tion Models

    “Machine translit­er­a­tion is a method for auto­mat­i­cally con­vert­ing words in one lan­guage into pho­net­i­cally equiv­a­lent ones in another lan­guage. Machine translit­er­a­tion plays an impor­tant role in nat­ural lan­guage appli­ca­tions such as infor­ma­tion retrieval and machine trans­la­tion, espe­cially for han­dling proper nouns and tech­ni­cal terms. Four machine translit­er­a­tion mod­els — grapheme-​​based translit­er­a­tion model, phoneme-​​based translit­er­a­tion model, hybrid translit­er­a­tion model, and correspondence-​​based translit­er­a­tion model — have been pro­posed by sev­eral researchers. To date, how­ever, there has been lit­tle research on a frame­work in which mul­ti­ple translit­er­a­tion mod­els can oper­ate simul­ta­ne­ously. Fur­ther­more, there has been no com­par­i­son of the four mod­els within the same frame­work and using the same data. We addressed these prob­lems by 1) mod­el­ing the four mod­els within the same frame­work, 2) com­par­ing them under the same con­di­tions, and 3) devel­op­ing a way to improve machine translit­er­a­tion through this com­par­i­son. Our com­par­i­son showed that the hybrid and correspondence-​​based mod­els were the most effec­tive and that the four mod­els can be used in a com­ple­men­tary man­ner to improve machine translit­er­a­tion performance.”

    natural-​​language-​​processing machine-​​learning review nudge-​​targets
  • [1108.5508] A Pat­tern Measure

    “In this paper we pro­pose numer­i­cal mea­sures for eval­u­at­ing the aes­thetic inter­est of sim­ple pat­terns. The pat­terns con­sist of ele­ments (sym­bols, pix­els, etc.) in reg­u­lar square arrays. The mea­sures depend on two char­ac­ter­is­tics of the pat­terns: the num­ber of dif­fer­ent types of ele­ment, and the num­ber of sym­me­tries in their arrange­ment. We define two com­ple­men­tary com­pos­ite mea­sures L and C for the degree of pat­tern in a design, and com­pute them here for 2×2 and 6×6 arrays. The results dis­tin­guish sim­ple from high-​​variation cases. We sus­pect that the mea­sure L cor­re­sponds to the degree that human beings intu­itively feel a design to be “inter­est­ing”, so this model would aid in quan­ti­fy­ing the visual con­nec­tion of two– dimen­sional designs with view­ers. The other com­pos­ite mea­sure C based on these numer­i­cal prop­er­ties char­ac­ter­izes the extent of ran­dom­ness of an array. Com­bin­ing sym­bol vari­ety with sym­me­try cal­cu­la­tions allows us to employ hier­ar­chi­cal scal­ing to count the rel­a­tive impact of dif­fer­ent lev­els of scale. By iden­ti­fy­ing sub­struc­tures we can dis­tin­guish between orga­nized pat­terns and dis­or­ga­nized com­plex­ity. The mea­sures described here are related to ver­bal descrip­tors derived from work by psy­chol­o­gists on responses to visual environments.”

    cog­ni­tion aes­thet­ics experimental-​​psychology nudge-​​targets learning-​​by-​​watching
  • [1106.5264] Acquir­ing Cor­rect Knowl­edge for Nat­ural Lan­guage Generation

    “Nat­ural lan­guage gen­er­a­tion (NLG) sys­tems are com­puter soft­ware sys­tems that pro­duce texts in Eng­lish and other human lan­guages, often from non-​​linguistic input data. NLG sys­tems, like most AI sys­tems, need sub­stan­tial amounts of knowl­edge. How­ever, our expe­ri­ence in two NLG projects sug­gests that it is dif­fi­cult to acquire cor­rect knowl­edge for NLG sys­tems; indeed, every knowl­edge acqui­si­tion (KA) tech­nique we tried had sig­nif­i­cant prob­lems. In gen­eral terms, these prob­lems were due to the com­plex­ity, nov­elty, and poorly under­stood nature of the tasks our sys­tems attempted, and were wors­ened by the fact that peo­ple write so dif­fer­ently. This meant in par­tic­u­lar that corpus-​​based KA approaches suf­fered because it was impos­si­ble to assem­ble a siz­able cor­pus of high-​​quality con­sis­tent man­u­ally writ­ten texts in our domains; and struc­tured expert-​​oriented KA tech­niques suf­fered because experts dis­agreed and because we could not get enough infor­ma­tion about spe­cial and unusual cases to build robust sys­tems. We believe that such prob­lems are likely to affect many other NLG sys­tems as well. In the long term, we hope that new KA tech­niques may emerge to help NLG sys­tem builders. In the shorter term, we believe that under­stand­ing how indi­vid­ual KA tech­niques can fail, and using a mix­ture of dif­fer­ent KA tech­niques with dif­fer­ent strengths and weak­nesses, can help devel­op­ers acquire NLG knowl­edge that is mostly correct.”

    natural-​​language-​​processing artificial-​​intelligence interesting-​​problems high-​​hanging-​​fruit machine-​​learning nudge-​​targets
  • [1105.2423] Cytoskele­ton and Cell Motility

    “The present arti­cle is an invited con­tri­bu­tion to the Ency­clo­pe­dia of Com­plex­ity and Sys­tem Sci­ence, Robert A. Mey­ers Ed., Springer New York (2009). It is a review of the bio­phys­i­cal mech­a­nisms that underly cell motility.…”

    bio­physics biol­ogy review i-​​used-​​to-​​do-​​this-​​stuff lovely
  • [1110.0671] Width Dis­tri­b­u­tions for Con­vex Reg­u­lar Polyhedra

    “The mean width is a mea­sure on three-​​dimensional con­vex bod­ies that enjoys equal sta­tus with vol­ume and sur­face area [Rota]. As the phrase sug­gests, it is the mean of a prob­a­bil­ity den­sity f. We ver­ify for­mu­las for mean widths of the reg­u­lar tetra­he­dron and the cube. Higher-​​order moments of f_​tetra and f_​cube have not been exam­ined until now. Assume that each poly­he­dron has edges of unit length. We deduce that the mean square width of the reg­u­lar tetra­he­dron is 1/3+(3+sqrt(3))/(3*pi) and the mean square width of the cube is 1+4/pi.”

    geom­e­try mathematical-​​recreations nudge-​​targets
  • [cs/​0305036] Using Dynamic Sim­u­la­tion in the Devel­op­ment of Con­struc­tion Machinery

    “As in the car indus­try for quite some time, dynamic sim­u­la­tion of com­plete vehi­cles is being prac­ticed more and more in the devel­op­ment of off-​​road machin­ery. How­ever, spe­cific ques­tions arise due not only to com­pany struc­ture and size, but espe­cially to the type of prod­uct. Tightly cou­pled, non-​​linear sub­sys­tems of dif­fer­ent domains make pre­dic­tion and opti­mi­sa­tion of the com­plete system’s dynamic behav­iour a chal­lenge. Fur­ther­more, the demand for ver­sa­tile machines leads to some­times con­tra­dic­tory tar­get require­ments and can turn the design process into a hunt for the least painful com­pro­mise. This can be avoided by pro­found sys­tem knowl­edge, assisted by simulation-​​driven prod­uct devel­op­ment. This paper gives an overview of joint research into this issue by Volvo Wheel Load­ers and Linkop­ing Uni­ver­sity on that mat­ter, lists the results of a related lit­er­a­ture review and intro­duces the term “oper­ate­abil­ity”. Rather than giv­ing detailed answers, the prob­lem space for ongo­ing and future research is exam­ined and pos­si­ble solu­tions are sketched.”

    engineering-​​design design-​​automation mod­el­ing dynamical-​​systems man­u­fac­tur­ing nudge-​​targets