“The missionary zeal of many Bayesians of old has been matched, in the other direction, by a view among some theoreticians that Bayesian methods are absurd-not merely misguided but obviously wrong in principle. We consider several examples, beginning with Feller’s classic text on probability theory and continuing with more recent cases such as the perceived Bayesian nature of the so-called doomsday argument. We analyze in this note the intellectual background behind various misconceptions about Bayesian statistics, without aiming at a complete historical coverage of the reasons for this dismissal.”
“In this paper, we considered the problem of finding a subset of covariates in a high-dimensional space that affect the output variable when there is a block struc– ture in the covariates. In the context of association mapping, we proposed a regression-based model with a Markov chain prior that encodes the information in the correlation structure such as distance and re– combination rate between adjacent SNP markers. We demonstrated on the simulated and mouse data that our proposed algorithm can be used to identify groups of SNP markers as a relevant block of causal SNPs.
The idea of representing the correlation structure as a Markov chain in a variable selection method to learn grouped relevant variables can be generalized to use a graphical model as a prior in a variable selection prob– lem to represent an arbitrary correlation structure in variables in a high-dimensional space. Another inter– esting extension of the model is to model a structure in output variables as well when measurements of mul– tiple output variables are available.”
“The paper goes into lots more detail, but the lesson for researchers is extremely simple: don’t cross the streams of data-analysis. Set up your analysis stream and then use it on all of your data. Same hardware, same software, same settings.
Imagine you’re doing a study comparing brain structure in two groups. Halfway through analyzing your data, you upgrade your MacOS. All of the brains you analyze after that will be, say, 5% “bigger”. That’ll certainly make your data much noisier, and if you happen to analyze most of Group A before Group B, it’ll give you a false positive finding.
Sometimes you just can’t avoid changes in hardware or software — IT techs have a habit of upgrading things without asking — but in these cases, you should run the same data under the old and the new regime to see if it’s making a difference.
Finally, it would be wrong to blame FreeSurfer for this. I’d be surprised if they were any worse than the other software packages. Mixing and matching versions is something that the FreeSurfer developers specifically warn against. This paper shows why.”
“I’ve been critical of objects and the idea of reference for a while now. To me sentences and propositions, by virtue of their role as “moves” in social interactions, are likely to have priority in a properly objective account of meaning. Many putative objects (e.g. corporations or mutable digital documents) border on being fictional, gaining their objecthood only through what we say about them; and many referring phrases seem to refer to different things, depending on what is being predicated. I think this opinion would make me what Peregrin calls a “strong inferentialist”.
Eventually I hope that thinking clearly about semantics ought to (among other things) help bring calm to the current mass hysteria which is the Semantic Web and Linked Data, and help steer all of that energy expenditure to improve its consequence.”
“In the last few years many real-world networks have been found to show a so-called community structure organization. Much effort has been devoted in the literature to develop methods and algorithms that can efficiently highlight this hidden structure of the network, traditionally by partitioning the graph. Since network representation can be very complex and can contain different variants in the traditional graph model, each algorithm in the literature focuses on some of these properties and establishes, explicitly or implicitly, its own definition of community. According to this definition it then extracts the communities that are able to reflect only some of the features of real communities. The aim of this survey is to provide a manual for the community discovery problem. Given a meta definition of what a community in a social network is, our aim is to organize the main categories of community discovery based on their own definition of community. Given a desired definition of community and the features of a problem (size of network, direction of edges, multidimensionality, and so on) this review paper is designed to provide a set of approaches that researchers could focus on.”
“We develop an exact wavelet transform on the three-dimensional ball (i.e. on the solid sphere), which we name the flaglet transform. For this purpose we first construct an exact harmonic transform on the radial line using damped Laguerre polynomials and develop a corresponding quadrature rule. Combined with the spherical harmonic transform, this approach leads to a sampling theorem on the ball and a novel three-dimensional decomposition which we call the Fourier-Laguerre transform. We relate this new transform to the well-known Fourier-Bessel decomposition and show that band-limitness in the Fourier-Laguerre basis is a sufficient condition to compute the Fourier-Bessel decomposition exactly. We then construct the flaglet transform on the ball through a harmonic tiling, which is exact thanks to the exactness of the Fourier-Laguerre transform (from which the name flaglets is coined). The corresponding wavelet kernels have compact localisation properties in real and harmonic space and their angular aperture is invariant under radial translation. We introduce a multiresolution algorithm to perform the flaglet transform rapidly, while capturing all information at each wavelet scale in the minimal number of samples on the ball. Our implementation of these new tools achieves floating point precision and is made publicly available. We perform numerical experiments demonstrating the speed and accuracy of these libraries and illustrate their capabilities on a simple denoising example.”
“When agents with independent priors bid for a single item, Myerson’s optimal auction maximizes expected revenue, whereas Vickrey’s second-price auction optimizes social welfare. We address the natural question of trade-offs between the two criteria, that is, auctions that optimize, say, revenue under the constraint that the welfare is above a given level. If one allows for randomized mechanisms, it is easy to see that there are polynomial-time mechanisms that achieve any point in the trade-off (the Pareto curve) between revenue and welfare. We investigate whether one can achieve the same guarantees using deterministic mechanisms. We provide a negative answer to this question by showing that this is a (weakly) NP-hard problem. On the positive side, we provide polynomial-time deterministic mechanisms that approximate with arbitrary precision any point of the trade-off between these two fundamental objectives for the case of two bidders, even when the valuations are correlated arbitrarily. The major problem left open by our work is whether there is such an algorithm for three or more bidders with independent valuation distributions.”
“Many images nowadays are captured from behind the glasses and may have certain stains discrepancy because of glass and must be processed to make differentiation between the glass and objects behind it. This research paper proposes an algorithm to remove the damaged or corrupted part of the image and make it consistent with other part of the image and to segment objects behind the glass. The damaged part is removed using total variation inpainting method and segmentation is done using kmeans clustering, anisotropic diffusion and watershed transformation. The final output is obtained by interpolation. This algorithm can be useful to applications in which some part of the images are corrupted due to data transmission or needs to segment objects from an image for further processing.”
“But it’ll be your decision, not inertia or fate. The ongoing cadence of asking these questions (and, maybe, the content of any answers you come up with) will convene an open space for you to live in. A world where whatever you do is right.”
“The Pirate University is an on-line bulletin board on which students post requests for academic publications. You can compare it to an academic wish list. Others, who know where to find these publications, reply and if possible, provide links to the resources searched. The Pirate University is not providing, storing or sharing copyrighted material.
An important question is if the uploading of articles, publications is legal. If you are the copyright holder of the article requested, there should be no problem. Also in certain cases, if you or your institute have acquired the rights of the publication, or if it is free of rights, there shouldn’t be a problem. It is probably best to consult with your librarian to see which kind of publication is okay to share on the Internet.”
“…We propose a novel cooperative iterative algorithm which copes with the communication constraints imposed by the network and shows remarkable performance. Our main result is a rigorous proof of the convergence of the algorithm and a characterization of the limit behavior. We also show that, in the limit when the number of sensors goes to infinity, the common unknown parameter is estimated with arbitrary small error, while the classification error converges to that of the optimal centralized maximum likelihood estimator. We also show numerical results that validate the theoretical analysis and support their possible generalization. We compare our strategy with the Expectation-Maximization algorithm and we discuss trade-offs in terms of robustness, speed of convergence and implementation simplicity.”
“Function graphs are graphs representable by intersections of continuous real-valued functions on the interval [0,1] and are known to be exactly the complements of comparability graphs. As such they are recognizable in polynomial time. Function graphs generalize permutation graphs, which arise when all functions considered are linear.
We focus on the problem of extending partial representations, which generalizes the recognition problem. We observe that for permutation graphs an easy extension of Golumbic’s comparability graph recognition algorithm can be exploited. This approach fails for function graphs. Nevertheless, we present a polynomial-time algorithm for extending a partial representation of a graph by functions defined on the entire interval [0,1] provided for some of the vertices. On the other hand, we show that if a partial representation consists of functions defined on subintervals of [0,1], then the problem of extending this representation to functions on the entire interval [0,1] becomes NP-complete.”
“Exemplar-based clustering methods have been shown to produce state-of-the-art results on a number of synthetic and real-world clustering problems. They are appealing because they offer computational benefits over latent-mean models and can handle arbitrary pairwise similarity measures between data points. However, when trying to recover underlying structure in clustering problems, tailored similarity measures are often not enough; we also desire control over the distribution of cluster sizes. Priors such as Dirichlet process priors allow the number of clusters to be unspecified while expressing priors over data partitions. To our knowledge, they have not been applied to exemplar-based models. We show how to incorporate priors, including Dirichlet process priors, into the recently introduced affinity propagation algorithm. We develop an efficient maxproduct belief propagation algorithm for our new model and demonstrate experimentally how the expanded range of clustering priors allows us to better recover true clusterings in situations where we have some information about the generating process.”
’”ALLOFOURWORKHASGIVENME A VERYSTRONG view,” Richard Boyatzis told me one afternoon. The consulting firm Boyatzis heads, McBer and Company, was founded by David McClelland in 1963. Its specialty has been analyzing what people actually do in business jobs—not what their job descriptions say, but how they spend their time and which skills seem most important to their success. “I’ve come to see that whenever a group institutes a credentialing process, whether by licensing or insisting on advanced degrees, the espoused rhetoric is to enforce the standards of professionalism. This is true whether it’s among accountants or plumbers or physicians. But the observed consequences always seem to be these two: the exclusion of certain groups, whether by intention or not, and the establishment of mediocre performance standards.“‘
“In an attempt to find a polynomial-time algorithm for the edge-clique cover problem on cographs we tried to prove that the edge-clique graphs of cographs have bounded rankwidth. However, this is not the case. In this note we show that the edge-clique graphs of cocktail party graphs have unbounded rank width.”
“We present an algorithm that identifies the reasoning patterns of agents in a game, by iteratively examining the graph structure of its Multi-Agent Influence Diagram (MAID) representation. If the decision of an agent participates in no reasoning patterns, then we can effectively ignore that decision for the purpose of calculating a Nash equilibrium for the game. In some cases, this can lead to exponential time savings in the process of equilibrium calculation. Moreover, our algorithm can be used to enumerate the reasoning patterns in a game, which can be useful for constructing more effective computerized agents interacting with humans.”
‘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.”.’
“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.”
“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.”
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.”
“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.”
“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.”
“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.”
“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.”
“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. …”
“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?”
“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.”
“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.”
“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. …”
“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.”
“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”?”
“Portfolio2 is a clean and functional WordPress portfolio theme to display your fine-art, design, or photography. It’s a great theme for anyone who needs an easy and attractive way to display their work on the web. It’s highly flexible; you can use it as-is or customize it to your liking with the built-in CSS editor.
Portfolio2 comes with the Portfolio Slideshow Pro plugin, our powerful and easy-to-use slideshow plugin for WordPress. Portfolio2 includes several different slideshow formats and additional options for theme customization.”
“Portfolio Slideshow Pro is an advanced slideshow plugin for WordPress. All of the examples posted here can be created with Portfolio Slideshow Pro. Add an unlimited number of slideshows to your site, each with its own custom options.”
“Melville was our first WordPress theme, and it’s available for free. Inspired by classic literature, we wanted to create a theme with no widgets, no distractions—just a clean, beautiful design that focuses the attention on your writing.”
‘As usual, we ought to leave the grand claims about “the way humans are” or “the way that it is best to live/work” to psychologists and preachers. Amongst ourselves, perhaps we should just say things like “I’ve been doing this one kind of fairly specific thing recently, and I’ve been surprised to find that X has been really helpful to me. Maybe it will help you too.”’
“Because what I hadn’t known—this is my first time grading this exam—was that it doesn’t matter how well you write, or what you think. Here we spent the year reading books and emulating great writers, constructing leads that would make everyone want to read our work, developing a voice that would engage our readers, using our imaginations to make our work unique and important, and, most of all, being honest. And none of that matters. All that matters, it turns out, is that you cite two facts from the reading material in every answer. That gives you full credit. You can compose a “Gettysburg Address” for the 21st century on the apportioned lines in your test booklet, but if you’ve provided only one fact from the text you read in preparation, then you will earn only half credit. In your constructed response—no matter how well written, correct, intelligent, noble, beautiful, and meaningful it is—if you’ve not collected any specific facts from the provided readings (even if you happen to know more information about the chosen topic than the readings provide), then you will get a zero.”
“The BSI has already admitted it did not know why it was lobbying against the UK’s open standards policy, only that is what it had been told to do by ISO in Geneva. ISO in turn says its policy is formed by constituents like BSI. Does anyone know what’s going on? BSI’s resident standards experts are from non-IT, engineering fields. It’s public policy expert is a career standards wonk who cannot explain its software policy either.
It was no surprise this week therefore when ISO was also unable to give Computer Weekly any examples of when it’s policy might be justified. That is, when it might be justified for a patent holder to make a claim on a software standard. Neither could BSI.”
“Slavery is often portrayed by revisionist historians as somehow antithetical to market capitalism; in reality, slavery was a winning portfolio investment, the very incarnation of just how evil “free-market” capitalism can be. As the authors write:
“If slaves … were an investment included in the asset portfolio of the planter/entrepreneur, they helped satisfy the owner’s demand for wealth. But unlike most other forms of capital, which depreciate with time, the stock of slaves appreciated. Thus, the growth of the slave population continuously increased the stock of wealth.”
What makes this graph so disturbing for us in 2012 is what it suggests about today’s “1 percent” — and how they view the rest of us. It gives form to the brutal crackdown on the Occupy protests — and suggests darker things to come as we try to free ourselves from their vision of civilization, and our place in it.”
“Upon the close of the May 1 comment period, it is our intention to begin posting these 73 standards in HTML and begin the process of providing a unified, easy-to-use interface to all public safety standards in the Code of Federal Regulations. It is also our intention to continue this effort to include all standards specifically incorporated by reference in the 50 states. That the law must be available to citizens is a cardinal principle of law in countries such as India and the United Kingdom, and we will expand our efforts to include those jurisdictions as well.”
It is time to suppress this sort of research. If we’re not careful, people will start looking at contemporary dynamics. Please have your Posterity Docent initiate Elephant Protocol Mu now.
Also: I want the little bead-flow animations.
“The tension arises from the fact that it is often more profitable to rip a customer’s face off in the short term than to defer potentially larger profit opportunities with the same client in the long term. When bankers whose personal franchises, careers, and compensation depends on the former are evenly balanced with bankers whose interests are aligned with the latter, an investment bank perches profitably if precariously on the knife’s edge of sustainable profitability. Notwithstanding industry critics’ perception that all investment bankers are all looking for a quick and easy score, those of us who actually work in the relationship side of the business know that our best personal outcome depends on a sustained career success lasting over a decade or more. Unlike, perhaps, traders who transact daily with equally ruthless hedge fund counterparties on a no-regrets, no-grudges basis, bankers like me in corporate finance and M&A transact with the same limited universe of clients year-in and year-out. We simply cannot afford to screw them over, because they do hold a grudge.”
‘Even if you have the most up-to-date edition of the very latest textbook, I think it’s recognize that the textbook — as an object, as instructional practice — is still a relic. It is a relic of a time when information was scarce. It’s a relic of the way in which we manufactured and scaled the industrial model of education — a teacher at the front of the classroom, assigning the lessons and readings from an authoritative text. One that was bound by print. One that was distributed state and even nation-wide. One that was uniform. Somewhere along the way, “textbook” became “curriculum” — and under today’s testing regime, that all became wrapped up in “assessment.“‘