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“We present a method for the reconstruction of networks, based on the order of nodes visited by a stochastic branching process. Our algorithm reconstructs a network of minimal size that ensures consistency with the data. Crucially, we show that global consistency with the data can be achieved through purely local considerations, inferring the neighbourhood of each node in turn. The optimisation problem solved for each individual node can be reduced to a Set Covering Problem, which is known to be NP-hard but can be approximated well in practice. We then extend our approach to account for noisy data, based on the Minimum Description Length principle. We demonstrate our algorithms on synthetic data, generated by an SIR-like epidemiological model.”
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Superweed Immunity to Monsanto Pesticide Means Opportunity for Competitors — Seeking Alpha“Eventually, a reversal towards smaller farms and less production of corn, soybeans and cotton may even result. Also, for a few years, U.S. input costs may escalate while other regions (not yet seeing superweeds) continue to use lower priced Roundup, making the cost of production lower in South America, for example. Consequent rising input costs here in the U.S. will include potentially higher new GMO seeds, chemicals, labor, and fuel. The volume of chemical use will potentially become much greater, more toxic, and more expensive.”
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Ideally, investors should be watchdogs of a sort as well, not slaves to boardspeak. “BP may face criminal charges based on their own internal documents. This would amplify any BP civil liabilities.”
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“What is the primary difference? Ultimately it comes down to the question of “exit”. As a founder, I have no interest in exit or liquidity. I am in business to run a business, not to run away from it. Or as Warren Buffet puts it: Our favorite holding period is forever.”
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“In our final video from the last Bay Area Quantifed Self Show&Tell meetup, here is Dan Brown explaining the microphone he embedded into an air mattress under his bed to track motion, snoring, and heartrate during sleep. He describes how he assembled his invention, the tools he used for analyzing his data, and why he had to stop the tracking experiment.”
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“Motivated by constraint-based CAD software, we develop the foundation for the rigidity theory of a very general model: the body-and-cad structure, composed of rigid bodies in 3D constrained by pairwise coincidence, angular and distance constraints. We identify 21 relevant geometric constraints and develop the corresponding infinitesimal rigidity theory for these structures. The classical body-and-bar rigidity model can be viewed as a body-and-cad structure that uses only one constraint from this new class. As a consequence, we identify a new, necessary, but not sufficient, counting condition for minimal rigidity of body-and-cad structures: nested sparsity. This is a slight generalization of the well-known sparsity condition of Maxwell.”
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“I see a future computing world which is networked and platform independent. And that means gatekeepers of bandwidth and content will be the winners in that world. Over the short-term Microsoft and the telcos will play their part in protecting their legacy franchises in these arenas. But ultimately, people just want to get their content when– and where– ever they can. And that means the organizations which dominate the multi-device interfaces of the future will take on a leading role in technology, perhaps the leading role.…”
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“This introduction is based on my experiences with using Protovis in my Visualization and Visual Communication class earlier this spring. While the concepts involved are really not that difficult, they are rather foreign to students who have not been exposed to functional programming. And since that is also the case for a lot of hobbyists and people wanting to do visualization who do not have a computer science background, I imagine they run into the same problems.”
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“But even if we substantially improve education, it won’t fully solve the problem. There will still be a need for quality jobs that are not all that dependent upon knowledge based skills. However, it’s harder to imagine an emerging set of industries that will provide the large number of quality jobs that we need to replace those lost from industries in decline.”
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“If countries like Germany start to have issues selling their treasury bonds, how long will it take before it impacts the global bond market? It shouldn’t take long. That’s why Europe cannot afford the same quantitative easing as the U.S. has done in the last year. Thus, the Greece Crisis is not well contained yet. Is the Great Depression Avoidable?”
Monthly Archives: June 2010
links for 2010-06-08
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“This would seem to argue that some old patterns endure, and that’s true. But think of the twists suggested by this new premium on human basics. Suppose you decided that you could get all the face-to-face you needed two days a week. Would that influence where you lived? Would the mountains or the shore start looking good to you? Suppose you decided that you could get all the face-to-face you needed three days a month. Would the Caribbean start looking good to you?”
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“If the government can take over giant global insurer AIG and the auto giant General Motors and replace their CEOs, in order to keep them financially solvent, it should be able to put BP’s north American operations into temporary receivership in order to stop one of the worst environmental disasters in U.S. history.”
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I want to make this sort of thing less newsworthy.
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“Object orientation provides a flexible framework for the implementation of the convolution of arbitrary distributions of real-valued random variables.
We discuss an algorithm which is based on the Discrete Fourier Transformation and its fast computability via the Fast Fourier Transformation. It directly applies to lattice-supported distributions. In the case of continuous distributions an additional discretization to a linear lattice is necessary and the resulting lattice-supported distributions are suitably smoothed after convolution.” -
“No matter who is technically in control of the company, i.e. receivership or not, the one thing that is needed is for the government to have the authority it needs to force the company to fully disclose all the information it has about the leak, and about how to stop it. It also needs to be able to force the company to take particular actions to stop the leak even if the actions demand so many resources it results in the company going bankrupt.…”
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“Ardmore’s experiment with its own local currency will be more than just a summer fling.
Four community banks have agreed to contribute a total of $10,000 to fund a return of Ardmore’s Downtown Dollars for the holiday shopping season.”
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“The most recent version of Protovis, the open-source visualization library that uses JavaScript and SVG, was just released not too long ago — this time with more layout and examples. This is especially helpful since Protovis was “designed to be learned by example.” Among the new stuff is the ever popular streamgraphs, along with the force-directed layout. With only 10 to 20 lines of code, you’ll have your viz, so lots of bang for the buck.”
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“For instance, there is the Rogue Factory unit producing “custom high-tech goods”—but “what would the black market of ‘special orders’ look like?” Benque asks. This “black market of ‘special orders’” for things like 3D-printed human organs would also be something quite extraordinary to see, given another two decades’ time and cheap-enough bio-ink.”
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awesome
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“SEI accuses FASB of acting like a monopoly. “Because FASB is a monopolist in the market for establishing financial accounting standards, their reliance on these terms constitutes a monopolistic position and restraint of trade,” said Narancic. “Relying on these terms, they’re effectively taking out a competitor, doing so unlawfully and based on unconscionable contract terms.”
The complaint acknowledges that FASB has been working with the International Accounting Standards Board on converging accounting standards and forming a global standard-setter, and that there are other groups involved in setting standards.”
links for 2010-06-07
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“Are “willful and flagrant violation” of safety and “intentional disregard” of safety criminal acts? Can they be criminal only if someone is injured or dies? These are questions that need to be addressed.”
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“Riff is a a recent spin-off project from Jesse Sielaff’s work to bring a Ruby-like language interpreter to the browser. Riff is a plugin for Racc (a LARL(1) parser generator for Ruby). Riff extends the output generation portions of Racc and writes javascript instead of Ruby. If you’re familiar with LALR grammars this should add a handy tool to your javascript arsenal.”
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“In addition to placing effective checks on the power of the captain, pirate government also provided harmony amongst the crewmembers. Harmony was essential to the business of piracy; pirates who got along with one another stood a better chance of success in their ventures. The author writes that, “Contrary to popular wisdom, pirate life was orderly and honest” (45). In order to maintain order and ensure honesty, pirates drew up “Codes,” which outlined shipboard rules and regulations, and provided incentives to maximize individual effort. Each crew drew up its own constitution and ratified it by unanimous consent. …”
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“Everything we create should aspire to this, should leave us – as programmers – wondering if that’s all and if we shouldn’t perhaps add a bit more. Scott Berkun (a genius and a craftsman) said all of this more than ten years ago and I’ve known about it for at least half that time, but it hasn’t really changed the way I write software because it’s too hard to just know when something’s simple enough.”
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“During the century separating the 1830s from the 1930s, proponents of laissez-faire were so successful in advocating an economy that purportedly operated independent of the political system that New Deal supporters had to convince voters that the government could (and should) intervene economically on behalf of suffering Americans. In the 1930s, Dorothea Lange used a technology unavailable in 1837 to photograph the plight of economic victims in her composition “Migrant Mother.” Shot in a California pea picker’s camp during the Great Depression for the government’s Farm Security Administration, the photograph is strikingly similar to “Specie Claws.” The posture of the central characters is nearly identical. Both pictures appeal to emotion to make an argument about the effects of economic events on families.…”
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“… This was not because they doubted whether there was a moral imperative to pay one’s debts. Rather, they were shocked to see the idea of bank credit, based as it was on getting something for nothing, vying for the moral high ground. Credit of this sort was a speculation. Allowing it to flourish was one thing; granting it not only legitimacy, but moral status was horrific. If people were taught to consider their relationship with their banker as analogous to their obligations toward family, community, and state, the multitudes would indeed have come to ruin.”
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“… The Panic of 1837 launched America’s biggest and most consequential economic depression before the Civil War. And it was the decisions and behavior of thousands of actors like Bieller that created a perfect financial storm: bringing an end to one kind of capitalist boom; destroying the confidence of the slaveholding class, impoverishing millions of workers and farmers who were linked to the global economy; demolishing the already disrupted lives of hundreds of thousands of people like Harry and Roberson.…”
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“What, then, is the status of the crisis/knowledge nexus today, especially in light of an ascendant neo-liberalism that criticizes the earlier notions of social justice and obligation? Crisis continues to be capitalism’s mode of operation. According to Naomi Klein’s recent “disaster capitalism” argument, emergencies around the globe, including natural catastrophes, are now used to impose radical free-market policies. As for knowledge, government– and business-produced information is omnipresent and effortlessly accessible. Expert culture is thriving.…”
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‘An experienced investment manager said it well: “The best time to buy stocks is when you hear the term, ‘stock market,’ and you want to throw up.”’
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“The folks at CreditSuisse have created a new figure making this point by re-ranking sovereigns according to credit risk based on this multifactor model. The upshot is that China, Germany, Switzerland, the U.S., Australia, Japan, and Canada lead the way in terms of least sovereign credit risk. Agree or disagree with the absolute levels from the model, the point stands that naive models of sovereign risk are mostly fodder for idiotic headline writers, not helpful standalone measures for assessing real risk.”
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“We overview our recently introduced theory of n-fold integer programming which enables the polynomial time solution of fundamental linear and nonlinear integer programming problems in variable dimension. We demonstrate its power by obtaining the first polynomial time algorithms in several application areas including multicommodity flows and privacy in statistical databases.”
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“Where does this all leave us? The rest of the world is intent on pursuing a begger thy neighbor strategy, with the US being the neighbor. I suspect US policymakers will eventually relent; it will be the only choice left. All we can do now is sit back and wait for the inevitable explosion in the US trade deficit, waiting idly by for the next crisis and the “chance” to bring some sanity to the global financial architecture.”
links for 2010-06-05
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“We consider the problem of developing an efficient multi-threaded implementation of the matrix-vector multiplication algorithm for sparse matrices with structural symmetry. Matrices are stored using the compressed sparse row-column format (CSRC), designed for profiting from the symmetric non-zero pattern observed in global finite element matrices. Unlike classical compressed storage formats, performing the sparse matrix-vector product using the CSRC requires thread-safe access to the destination vector. To avoid race conditions, we have implemented two partitioning strategies. In the first one, each thread allocates an array for storing its contributions, which are later combined in an accumulation step. We analyze how to perform this accumulation in four different ways.…”
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“We present a method for estimating the complexity of an image based on the concept of logical depth. Unlike the application of the concept of algorithmic complexity by itself, the addition of the concept of logical depth results in a characterization of objects by organizational (physical) complexity. We use this measure to classify images by their information content. The method provides a means for evaluating and classifying objects by way of their visual representations.”
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“We consider methods for finding high-precision approximations to simple zeros of smooth functions. As an application, we give fast methods for evaluating the elementary functions log(x), exp(x), sin(x) etc. to high precision. For example, if x is a positive floating-point number with an n-bit fraction, then (under rather weak assumptions) an n-bit approximation to log(x) or exp(x) may be computed in time asymptotically equal to 13M(n)lg(n), where M(n) is the time required to multiply floating-point numbers with n-bit fractions. Similar results are given for the other elementary functions.…”
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“In this short note we have produced different kind of magic squares using digital letter having only the algorisms: 0, 1, 2, 5, and 8. The interesting fact in considering these five digits is that the day 8th May 2010 also have these ones (08.05.2010). Moreover, the magic squares presented have some interesting properties, such as: they remains the same if we rotate them by 180 degree, or see in the mirror, or see on the other side of the paper, etc. Two palindrome semi-magic squares of order 3×3 are also given. Still, we have considered other dates having four digits.”
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“In this paper, the performances of the quasi-Newton BFGS algorithm, the NEWUOA derivative free optimizer, the Covariance Matrix Adaptation Evolution Strategy (CMA-ES), the Differential Evolution (DE) algorithm and Particle Swarm Optimizers (PSO) are compared experimentally on benchmark functions reflecting important challenges encountered in real-world optimization problems. Dependence of the performances in the conditioning of the problem and rotational invariance of the algorithms are in particular investigated.”
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‘While “self-styled” seems mostly a put-down, it is a notably weak one. The user of this phrase notes that someone claims something, but lacks an official credential, or strong consensus, supporting this claim. But we the reader can also note that this speaker offers no stronger criticism, and is not willing to directly contradict the offending claim. After all, instead of calling someone a “self-styled visionary,” you might say “he calls himself a visionary, but he’s not; he hasn’t has a vision in years.”’
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“In this paper we present a novel genetic algorithm (GA) solution to a simple yet challenging commercial puzzle game known as the Zen Puzzle Garden (ZPG). We describe the game in detail, before presenting a suitable encoding scheme and fitness function for candidate solutions. We then compare the performance of the genetic algorithm with that of the A* algorithm. Our results show that the GA is competitive with informed search in terms of solution quality, and significantly out-performs it in terms of computational resource requirements. We conclude with a brief discussion of the implications of our findings for game solving and other “real world” problems.”
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“Thanks to recent technological advances, it is now possible to track with an unprecedented precision and for long periods of time the movement patterns of many living organisms in their habitat. The increasing amount of data available on single trajectories offers the possibility of understanding how animals move and of testing basic movement models. Random walks have long represented the main description for micro-organisms and have also been useful to understand the foraging behaviour of large animals. Nevertheless, most vertebrates, in particular humans and other primates, rely on sophisticated cognitive tools such as spatial maps, episodic memory and travel cost discounting. These properties call for other modeling approaches of mobility patterns. We propose a foraging framework where a learning mobile agent uses a combination of memory-based and random steps. We investigate how advantageous it is to use memory for exploiting resources in heterogeneous and changing environments.…”
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“Google and the USPTO have entered into an agreement to make the following USPTO products available to the public at no charge:
Patents (grants, applications, assignments, classification information, and maintenance fee events)
Trademarks (grants, applications, assignments, and TTAB proceedings)All data originated from the USPTO. Google is hosting this data unchanged, except for repackaging into zip files.”
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“The goal of topology optimization is to find optimal material distribution in the given design domain subject to some constraints governed by certain physical properties and/or some other practical constraints during the design. In the past two decades, advances in the theory of homogenization, optimization, numerical analysis as well as newly developed engineering approaches make topology opti– mization techniques to become a standard tool of engineering design, in particular in the field of structural mechanics.”
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“Shorter — there really is an urgent and perilous threat to Israel. It’s called “the Israeli government”.”
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“Algorithmic historiography was proposed by Eugene Garfield in collaboration with Irving Sher in the 1960s, but further developed only recently into HistCite^{TM} with Alexander Pudovkin. As in history writing, HistCite^{TM} reconstructs by drawing intellectual lineages. In addition to cited references, however, documents can be attributed a multitude of other variables such as title words, keywords, journal names, author names, and even full texts. New developments in multidimensional scaling (MDS) enable us not only to visualize these patterns at each moment of time, but also to animate them over time. Using title words, co-authors, and journal names in Garfield’s oeuvre, the method is demonstrated and further developed in this paper (and in the animation at this http URL). The variety and substantive content of the animation enables us to write, visualize, and animate the author’s intellectual history.”
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“We formalize the procedure of adaptation of a TSP neighborhood for GTSP and propose efficient algorithms to explore the obtained neighborhoods. We also generalize all other existing and some new GTSP neighborhoods. Apart from these theoretical results, we also provide the results of a thorough experimental analysis to compare the proposed algorithms implementations and find out which neighborhoods are the most efficient in practice.”
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“We use three-dimensional phase-field simulations to investigate the dynamics of the two-phase composite patterns formed upon during solidification of eutectic alloys. Besides the spatially periodic lamellar and rod patterns that have been widely studied, we find that there is a large number of additional steady-state patterns which exhibit stable defects. The defect density can be so high that the pattern is completely disordered, and that the distinction between lamellar and rod patterns is blurred. As a consequence, the transition from lamellae to rods is not sharp, but extends over a finite range of compositions and exhibits strong hysteresis. Our findings are in good agreement with experiments.”
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“Since multivariate Boltzmann samplers can be obtained in any situation where the distribution is well-concentrated, one may envision extensions to other classes, including constrained trees, permu– tations with a fixed number of cycles, functional graphs with a controlled number of components.…”
links for 2010-06-04
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“We’ve all heard it: according to Hal Varian, statistics is the next sexy job. Five years ago, in What is Web 2.0, Tim O’Reilly said that “data is the next Intel Inside.” But what does that statement mean? Why do we suddenly care about statistics and about data?
In this post, I examine the many sides of data science — the technologies, the companies and the unique skill sets.”
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“This memo considers three radical ideas applying to the Web, not necessarily as serious proposals (although given support they could be turned into such) but as thought experiments or fantasies meant to sharpen the discussion of the “meaning” of URIs and other current issues of web architecture. The first fantasy is the idea that a URI’s meaning is in how it is used, not what it “identifies”. The second is the prospect of second sourcing for URI behavior. The third is the idea of encyclopedia-style documentation for URIs.”