These are my recent Pinboard.in links:
Cinderella Documentation : Theoretical Background
“At first sight it is not clear whether this requirement is satisfiable in general. Turn on your favorite system for doing interactive geometry or parametric CAD and make the following experiment: Draw a horizontal line and construct two circles of equal radius whose centers are constrained to slide along the line. Move the circles to a position in which they intersect, and construct the upper point of intersection of the two circles. Now move one circle so that its center passes through the center of the other circle. Most probably you will see that the point of intersection suddenly jumps from the upper intersection to the lower one. This is what has happened in all the systems we have tried so far. Such behavior runs counter to our requirement of continuity: You make a small move, and a dependent point suddenly jumps.”
simulation geometry algorithms representation nudge-targets- “He talks about items ranging from multicultural sensitivities to taking the arts serious to “being famous for helping the poor.” The latter was an item that jumped out at me because, as I’ve noted before, too many urbanist arguments are basically arguments for what I call “Starbucks urbanism.” If called on this, people will say, “But of course transit will benefit the poor too.” But that’s not how it’s sold. Urbanists ought to be famous for the way they design, implement, and talk about their policies as instruments for helping the poor and facilitating upward economic and social mobility. There’s a lot of other good stuff in the video that’s relevant to urbanism. For those who prefer reading, Keller also wrote a paper called “Our New Global Culture: Ministry in Cities, which says of itself: “This paper surveys the rise of global cities, the culture and dominant worldviews within these cities, and a framework for ministering in them.”?
city-planning organization marketing Workantile Coscience outreach diversity management Study Hacks » Blog Archive » What You Know Matters More Than What You Do
“According to my colleagues, this star researcher tends to begin with techniques, not problems. He first masters a technique that seems promising (and when I say “master,” I mean it — he really goes deep in building his understanding). He then uses this new technique to seek out problems that were once hard but now yield easily. He’s restless in this quest, often mastering several new techniques each year.”
heuristics worklife innovation productivity problem-seeing problem-solvingJournatic worker takes ‘This American Life’ inside outsourced journalism | Poynter.
“If you’ve never heard of Journatic, that’s kind of the idea. The company, which was founded in 2006, has a website that doesn’t appear on at least the first five pages of Google search results. Job openings, often posted on Craigslist or JournalismJobs.com, once mentioned the company’s name, but no longer. Journatic currently works with “dozens” of media companies, Timpone said, though he declined to name them. He’s spoken before of the real estate section Journatic produces for the San Francisco Chronicle. He said more are signing up all the time.”
disintermediation-in-action journalism worklife outsourcing exposé- “Tribal Leaders are the people who focus their efforts on upgrading the tribal culture. (upgrading the words we use to describe our reality and the behaviors we practice that shape the direction of our lives) They set the standard of performance in their industries, from productivity and profitability to employee retention, and attract talent. Most of all, they help bring groups to unity by recognizing their ‘tribalness’ – getting people to talk about the things they really care about, coming together around these common causes, and forming missions to make something great happen, and to live in greatness. The goal of Tribal Leadership is to learn how to get people ‘unstuck’ – from unhelpful language and behaviors, so we can level up and transition into higher-performance, less stressful, and more fun states of Being.”
i-hate-the-word-tribes collaboration leadership cultural-dynamics advice [1206.6532] Estimating Nuisance Parameters in Inverse Problems
“Many inverse problems include nuisance parameters which, while not of direct interest, are required to recover primary parameters. Structure present in these problems allows efficient optimization strategies — a well known example is variable projection, where nonlinear least squares problems which are linear in some parameters can be very efficiently optimized. In this paper, we extend the idea of projecting out a subset over the variables to a broad class of maximum likelihood (ML) and maximum a posteriori likelihood (MAP) problems with nuisance parameters, such as variance or degrees of freedom. As a result, we are able to incorporate nuisance parameter estimation into large-scale constrained and unconstrained inverse problem formulations. We apply the approach to a variety of problems, including estimation of unknown variance parameters in the Gaussian model, degree of freedom (d.o.f.) parameter estimation in the context of robust inverse problems, automatic calibration, and optimal experimental design. Using numerical examples, we demonstrate improvement in recovery of primary parameters for several large– scale inverse problems. The proposed approach is compatible with a wide variety of algorithms and formulations, and its implementation requires only minor modifications to existing algorithms.”
reinventing-the-wheel feature-extraction optimization modeling-is-not-mathematics nudge-targets[1206.4608] A Hybrid Algorithm for Convex Semidefinite Optimization
“We present a hybrid algorithm for optimizing a convex, smooth function over the cone of positive semidefinite matrices. Our algorithm converges to the global optimal solution and can be used to solve general large-scale semidefinite programs and hence can be readily applied to a variety of machine learning problems. We show experimental results on three machine learning problems (matrix completion, metric learning, and sparse PCA) . Our approach outperforms state-of-the-art algorithms.”
algorithms optimization computational-complexity specialization nudge-targets- “For many of the unsolved problems concerning cycles and matchings in graphs it is known that it is sufficient to prove them for emph{snarks}, the class of nontrivial 3-regular graphs which cannot be 3-edge coloured. In the first part of this paper we present a new algorithm for generating all non-isomorphic snarks of a given order. Our implementation of the new algorithm is 14 times faster than previous programs for generating snarks, and 29 times faster for generating weak snarks. Using this program we have generated all non-isomorphic snarks on $nleq 36$ vertices. Previously lists up to $n=28$ vertices have been published. In the second part of the paper we analyze the sets of generated snarks with respect to a number of properties and conjectures. We find that some of the strongest versions of the cycle double cover conjecture hold for all snarks of these orders, as does Jaeger’s Petersen colouring conjecture, which in turn implies that Fulkerson’s conjecture has no small counterexamples. In contrast to these positive results we also find counterexamples to eight previously published conjectures concerning cycle coverings and the general cycle structure of cubic graphs.”
graph-theory combinatorics algorithms nudge-targets [1206.6238] Entrainability enhancement by period mismatch in biloop genetic oscillators
“Effects of the period mismatch on entrainment properties in two coupled genetic oscillators are studied. The entrainment is calculated with a phase reduction approach and a Floquet multiplier analysis, and their dependencies on coupling strength and the period ratio are investigated in two genetic oscillator models (smooth and relaxation oscillators). We find that the existence of the period mismatch induces an enhancement of entrainment in both smooth and relaxation oscillators. By calculating Floquet multipliers, we show that the enhancement mechanism is based on the coupled oscillators which are in the vicinity of bifurcation on limit cycle.”
biological-engineering emergent-design reaction-networks oscillators control-theory[1206.4672] Efficient Active Algorithms for Hierarchical Clustering
“Advances in sensing technologies and the growth of the internet have resulted in an explosion in the size of modern datasets, while storage and processing power continue to lag behind. This motivates the need for algorithms that are efficient, both in terms of the number of measurements needed and running time. To combat the challenges associated with large datasets, we propose a general framework for active hierarchical clustering that repeatedly runs an off-the-shelf clustering algorithm on small subsets of the data and comes with guarantees on performance, measurement complexity and runtime complexity. We instantiate this framework with a simple spectral clustering algorithm and provide concrete results on its performance, showing that, under some assumptions, this algorithm recovers all clusters of size ?(log n) using O(n log^2 n) similarities and runs in O(n log^3 n) time for a dataset of n objects. Through extensive experimentation we also demonstrate that this framework is practically alluring.”
clustering algorithms nudge-targets practically-alluring- “This episode shows clearer than ever that the copyright and patent monopolies are not intended to be protective of innovation or protective of the economy. They’re obviously too complex even for their strongest supporters and lobbyists to understand and adhere to. Rather, they are intended as legal clubs to be used by the now-rich incumbents against resource-strapped upstarts. The copyright and patent monopolies are only protective of the past, protective against the present and future of innovation, creativity, and economy.”
copyright intellectual-property corporatism public-policy [1112.5218] Patterns of neutral diversity under general models of selective sweeps
“Two major sources of stochasticity in the dynamics of neutral alleles result from resampling of finite populations (genetic drift) and the random genetic background of nearby selected alleles on which the neutral alleles are found (linked selection). There is now good evidence that linked selection plays an important role in shaping polymorphism levels in a number of species. One of the best investigated models of linked selection is the recurrent full sweep model, in which newly arisen selected alleles fix rapidly. However, the bulk of selected alleles that sweep into the population may not be destined for rapid fixation. Here we develop a general model of recurrent selective sweeps in a coalescent framework, one that generalizes the recurrent full sweep model to the case where selected alleles do not sweep to fixation. We show that in a large population, only the initial rapid increase of a selected allele affects the genealogy at partially linked sites, which under fairly general assumptions are unaffected by the subsequent fate of the selected allele. We also apply the theory to a simple model to investigate the impact of recurrent partial sweeps on levels of neutral diversity, and find that for a given reduction in diversity, the impact of recurrent partial sweeps on the frequency spectrum at neutral sites is determined primarily by the frequencies achieved by the selected alleles. Consequently, recurrent sweeps of selected alleles to low frequencies can have a profound effect on levels of diversity but can leave the frequency spectrum relatively unperturbed. In fact, the limiting coalescent model under a high rate of sweeps to low frequency is identical to the standard neutral model. The general model of selective sweeps we describe goes some way towards providing a more flexible framework to describe genomic patterns of diversity than is currently available.”
neutral-networks evolutionary-dynamics fitness-landscapes diversity theoretical-biology- “In the presence of highways, dealing with more general network settings would be desirable. Also our definition of highways as connecting two edges is somewhat restrictive. In general, one is also interested in preferential genetic transfers between clades.”
algorithms lateral-gene-transfer cladistics phylogenetics inverse-problems ontology modeling-is-not-mathematics nudge-targets - “Nonparametric Bayesian models are often based on the assumption that the objects being modeled are exchangeable. While appropriate in some applications (e.g., bag-of-words models for documents), exchangeability is sometimes assumed simply for computational reasons; non-exchangeable models might be a better choice for applications based on subject matter. Drawing on ideas from graphical models and phylogenetics, we describe a non-exchangeable prior for a class of nonparametric latent feature models that is nearly as efficient computationally as its exchangeable counterpart. Our model is applicable to the general setting in which the dependencies between objects can be expressed using a tree, where edge lengths indicate the strength of relationships. We demonstrate an application to modeling probabilistic choice.”
statistics algorithms ontology colligation feature-extraction philosophy-of-science nudge-targets “The Eurozone’s Strategy is a Disaster” « naked capitalism
“Why should German and other taxpayers, mostly from the north, pay for the others, mostly from the south? Because their governments are responsible for the disastrous situation we are in.”
financial-crisis public-policy economics cultural-dynamics fair-weather-bosses[1206.6504] An Abstract Approach to Stratification in Linear Logic
“We study the notion of stratification, as used in subsystems of linear logic with low complexity bounds on the cut-elimination procedure (the so-called light logics), from an abstract point of view, introducing a logical system in which stratification is handled by a separate modality. This modality, which is a generalization of the paragraph modality of Girard’s light linear logic, arises from a general categorical construction applicable to all models of linear logic. We thus learn that stratification may be formulated independently of exponential modalities; when it is forced to be connected to exponential modalities, it yields interesting complexity properties. In particular, from our analysis stem three alternative reformulations of Baillot and Mazza’s linear logic by levels: one geometric, one interactive, and one semantic.”
linear-logic logic-programming formalization nudge-targets representation- “Holding on to one’s strategy is natural and common if the later warrants success and satisfaction. This goes against widespread simulation practices of evolutionary games, where players frequently consider changing their strategy even though their payoffs may be marginally different than those of the other players. Inspired by this observation, we introduce an aspiration-based win-stay-lose-learn strategy updating rule into the spatial prisoner’s dilemma game. The rule is simple and intuitive, foreseeing strategy changes only by dissatisfied players, who then attempt to adopt the strategy of one of their nearest neighbors, while the strategies of satisfied players are not subject to change. We find that the proposed win-stay-lose-learn rule promotes the evolution of cooperation, and it does so very robustly and independently of the initial conditions. In fact, we show that even a minute initial fraction of cooperators may be sufficient to eventually secure a highly cooperative final state. In addition to extensive simulation results that support our conclusions, we also present results obtained by means of the pair approximation of the studied game. Our findings continue the success story of related win-stay strategy updating rules, and by doing so reveal new ways of resolving the prisoner’s dilemma.”
game-theory agent-based complexology - “And there’s everything you need to know about the Republican Party. “Shit happened, but so what? People were victimized, but why should we care? That was nearly forty years ago.” The dementia in refusing to look backward, refusing to make up for the mistakes of the past, whether it’s the Bush tax cuts or the lies that got us into war or the lies that got us into this financial crisis, makes us damned to repeat. ”
summary politics Republicans