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Do What You Can Do with Cellist Joshua Roman

Legendary musician Yo-Yo Ma called my guest today the future of classical music in America. Joshua Roman is a cellist, accomplished composer and curator whose performances embrace musical styles from Bach to Radiohead. At 22, he became the youngest principal cellist in the Seattle Symphony. Now as a soloist, his performances have been viewed by millions. I was able to catch up with Joshua on this special LIVE performance CreativeLive TV. Wherever you are in the world, hope this episode lifts you up. Please be sure to give Joshua a shout on the socials. Enjoy! FOLLOW JOSHUA: instagram | twitter | website Listen to the Podcast Subscribe   Watch the Episode This podcast is brought to you by CreativeLive. CreativeLive is the world’s largest hub for online creative education in photo/video, art/design, music/audio, craft/maker, money/life and the ability to make a living in any of those disciplines. They are high quality, highly curated classes taught by the world’s top experts — Pulitzer, Oscar, Grammy Award winners, New York Times best selling authors and the best entrepreneurs of our times.

The post Do What You Can Do with Cellist Joshua Roman appeared first on Chase Jarvis Photography.




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Markdown Comes Alive! Part 1, Basic Editor

In my last post, I covered what LiveView is at a high level. In this series, we’re going to dive deeper and implement a LiveView powered Markdown editor called Frampton. This series assumes you have some familiarity with Phoenix and Elixir, including having them set up locally. Check out Elizabeth’s three-part series on getting started with Phoenix for a refresher.

This series has a companion repository published on GitHub. Get started by cloning it down and switching to the starter branch. You can see the completed application on master. Our goal today is to make a Markdown editor, which allows a user to enter Markdown text on a page and see it rendered as HTML next to it in real-time. We’ll make use of LiveView for the interaction and the Earmark package for rendering Markdown. The starter branch provides some styles and installs LiveView.

Rendering Markdown

Let’s set aside the LiveView portion and start with our data structures and the functions that operate on them. To begin, a Post will have a body, which holds the rendered HTML string, and title. A string of markdown can be turned into HTML by calling Post.render(post, markdown). I think that just about covers it!

First, let’s define our struct in lib/frampton/post.ex:

defmodule Frampton.Post do
  defstruct body: "", title: ""

  def render(%__MODULE{} = post, markdown) do
    # Fill me in!
  end
end

Now the failing test (in test/frampton/post_test.exs):

describe "render/2" do
  test "returns our post with the body set" do
    markdown = "# Hello world!"                                                                                                                 
    assert Post.render(%Post{}, markdown) == {:ok, %Post{body: "<h1>Hello World</h1>
"}}
  end
end

Our render method will just be a wrapper around Earmark.as_html!/2 that puts the result into the body of the post. Add {:earmark, "~> 1.4.3"} to your deps in mix.exs, run mix deps.get and fill out render function:

def render(%__MODULE{} = post, markdown) do
  html = Earmark.as_html!(markdown)
  {:ok, Map.put(post, :body, html)}
end

Our test should now pass, and we can render posts! [Note: we’re using the as_html! method, which prints error messages instead of passing them back to the user. A smarter version of this would handle any errors and show them to the user. I leave that as an exercise for the reader…] Time to play around with this in an IEx prompt (run iex -S mix in your terminal):

iex(1)> alias Frampton.Post
Frampton.Post
iex(2)> post = %Post{}
%Frampton.Post{body: "", title: ""}
iex(3)> {:ok, updated_post} = Post.render(post, "# Hello world!")
{:ok, %Frampton.Post{body: "<h1>Hello world!</h1>
", title: ""}}
iex(4)> updated_post
%Frampton.Post{body: "<h1>Hello world!</h1>
", title: ""}

Great! That’s exactly what we’d expect. You can find the final code for this in the render_post branch.

LiveView Editor

Now for the fun part: Editing this live!

First, we’ll need a route for the editor to live at: /editor sounds good to me. LiveViews can be rendered from a controller, or directly in the router. We don’t have any initial state, so let's go straight from a router.

First, let's put up a minimal test. In test/frampton_web/live/editor_live_test.exs:

defmodule FramptonWeb.EditorLiveTest do
  use FramptonWeb.ConnCase
  import Phoenix.LiveViewTest

  test "the editor renders" do
    conn = get(build_conn(), "/editor")
    assert html_response(conn, 200) =~ "data-test="editor""
  end
end

This test doesn’t do much yet, but notice that it isn’t live view specific. Our first render is just the same as any other controller test we’d write. The page’s content is there right from the beginning, without the need to parse JavaScript or make API calls back to the server. Nice.

To make that test pass, add a route to lib/frampton_web/router.ex. First, we import the LiveView code, then we render our Editor:

import Phoenix.LiveView.Router
# … Code skipped ...
# Inside of `scope "/"`:
live "/editor", EditorLive

Now place a minimal EditorLive module, in lib/frampton_web/live/editor_live.ex:

defmodule FramptonWeb.EditorLive do
  use Phoenix.LiveView

  def render(assigns) do
    ~L"""
      <div data-test=”editor”>
        <h1>Hello world!</h1>
      </div>
      """
  end

  def mount(_params, _session, socket) do
    {:ok, socket}
  end
end

And we have a passing test suite! The ~L sigil designates that LiveView should track changes to the content inside. We could keep all of our markup in this render/1 method, but let’s break it out into its own template for demonstration purposes.

Move the contents of render into lib/frampton_web/templates/editor/show.html.leex, and replace EditorLive.render/1 with this one liner: def render(assigns), do: FramptonWeb.EditorView.render("show.html", assigns). And finally, make an EditorView module in lib/frampton_web/views/editor_view.ex:

defmodule FramptonWeb.EditorView do
  use FramptonWeb, :view
  import Phoenix.LiveView
end

Our test should now be passing, and we’ve got a nicely separated out template, view and “live” server. We can keep markup in the template, helper functions in the view, and reactive code on the server. Now let’s move forward to actually render some posts!

Handling User Input

We’ve got four tasks to accomplish before we are done:

  1. Take markdown input from the textarea
  2. Send that input to the LiveServer
  3. Turn that raw markdown into HTML
  4. Return the rendered HTML to the page.

Event binding

To start with, we need to annotate our textarea with an event binding. This tells the liveview.js framework to forward DOM events to the server, using our liveview channel. Open up lib/frampton_web/templates/editor/show.html.leex and annotate our textarea:

<textarea phx-keyup="render_post"></textarea>

This names the event (render_post) and sends it on each keyup. Let’s crack open our web inspector and look at the web socket traffic. Using Chrome, open the developer tools, navigate to the network tab and click WS. In development you’ll see two socket connections: one is Phoenix LiveReload, which polls your filesystem and reloads pages appropriately. The second one is our LiveView connection. If you let it sit for a while, you’ll see that it's emitting a “heartbeat” call. If your server is running, you’ll see that it responds with an “ok” message. This lets LiveView clients know when they've lost connection to the server and respond appropriately.

Now, type some text and watch as it sends down each keystroke. However, you’ll also notice that the server responds with a “phx_error” message and wipes out our entered text. That's because our server doesn’t know how to handle the event yet and is throwing an error. Let's fix that next.

Event handling

We’ll catch the event in our EditorLive module. The LiveView behavior defines a handle_event/3 callback that we need to implement. Open up lib/frampton_web/live/editor_live.ex and key in a basic implementation that lets us catch events:

def handle_event("render_post", params, socket) do
  IO.inspect(params)

  {:noreply, socket}
end

The first argument is the name we gave to our event in the template, the second is the data from that event, and finally the socket we’re currently talking through. Give it a try, typing in a few characters. Look at your running server and you should see a stream of events that look something like this:

There’s our keystrokes! Next, let’s pull out that value and use it to render HTML.

Rendering Markdown

Lets adjust our handle_event to pattern match out the value of the textarea:

def handle_event("render_post", %{"value" => raw}, socket) do

Now that we’ve got the raw markdown string, turning it into HTML is easy thanks to the work we did earlier in our Post module. Fill out the body of the function like this:

{:ok, post} = Post.render(%Post{}, raw)
IO.inspect(post)

If you type into the textarea you should see output that looks something like this:

Perfect! Lastly, it’s time to send that rendered html back to the page.

Returning HTML to the page

In a LiveView template, we can identify bits of dynamic data that will change over time. When they change, LiveView will compare what has changed and send over a diff. In our case, the dynamic content is the post body.

Open up show.html.leex again and modify it like so:

<div class="rendered-output">
  <%= @post.body %>
</div>

Refresh the page and see:

Whoops!

The @post variable will only be available after we put it into the socket’s assigns. Let’s initialize it with a blank post. Open editor_live.ex and modify our mount/3 function:

def mount(_params, _session, socket) do
  post = %Post{}
  {:ok, assign(socket, post: post)}
end

In the future, we could retrieve this from some kind of storage, but for now, let's just create a new one each time the page refreshes. Finally, we need to update the Post struct with user input. Update our event handler like this:

def handle_event("render_post", %{"value" => raw}, %{assigns: %{post: post}} = socket) do
  {:ok, post} = Post.render(post, raw)
  {:noreply, assign(socket, post: post)
end

Let's load up http://localhost:4000/editor and see it in action.

Nope, that's not quite right! Phoenix won’t render this as HTML because it’s unsafe user input. We can get around this (very good and useful) security feature by wrapping our content in a raw/1 call. We don’t have a database and user processes are isolated from each other by Elixir. The worst thing a malicious user could do would be crash their own session, which doesn’t bother me one bit.

Check the edit_posts branch for the final version.

Conclusion

That’s a good place to stop for today. We’ve accomplished a lot! We’ve got a dynamically rendering editor that takes user input, processes it and updates the page. And we haven’t written any JavaScript, which means we don’t have to maintain or update any JavaScript. Our server code is built on the rock-solid foundation of the BEAM virtual machine, giving us a great deal of confidence in its reliability and resilience.

In the next post, we’ll tackle making a shared editor, allowing multiple users to edit the same post. This project will highlight Elixir’s concurrency capabilities and demonstrate how LiveView builds on them to enable some incredible user experiences.



  • Code
  • Back-end Engineering

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Godox’s new SL150/SL200 Mark II LED lights offer fanless “silent mode” operation

The Godox SL series LED lights have proven to be extremely popular due to their low cost. Two of the models in that range, the SL150 and SL200 have seen a Mark II update today, according to an email that Godox has been sending out today. One of the features of the new SL150II and […]

The post Godox’s new SL150/SL200 Mark II LED lights offer fanless “silent mode” operation appeared first on DIY Photography.










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eagereyesTV Episode 2: Unit Charts, Dot Plots, ISOTYPE, and What Makes Them Special

Charts usually show values as visual properties, like the length in a bar chart, the location in a scatterplot, the area in a bubble chart, etc. Unit charts show values as multiples instead. One famous example of these charts is called ISOTYPE, and you may have seen them in information graphics as well. They’re an […]




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Double Chance Picks *** Sunday *** 17 September 2017

We have a new preview on https://www.007soccerpicks.com/sunday-matches/double-chance-picks-sunday-17-september-2017/

Double Chance Picks *** Sunday *** 17 September 2017

DOUBLE CHANCE PICKS To return: ??? USD Odds: 2.80 Stake: 100 USD   Starting in   Teams   Our Prediction Odds Las Palmas - Ath Bilbao Soccer: Spain - LaLiga X2 1.45 Chievo - Atalanta Soccer: Italy - Serie…




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Double Chance Picks *** Monday *** 18 September 2017

We have a new preview on https://www.007soccerpicks.com/monday-matches/double-chance-picks-monday-18-september-2017/

Double Chance Picks *** Monday *** 18 September 2017

DOUBLE CHANCE PICKS To return: ??? USD Odds: 2.03 Stake: 100 USD   Starting in   Teams   Our Prediction Odds Espanyol - Celta Vigo Soccer: Spain - LaLiga 1X 1.29 AFC Eskilstuna - Sundsvall Soccer: Sweden -…




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Double Chance Picks *** Tuesday *** 19 September 2017

We have a new preview on https://www.007soccerpicks.com/tuesday-matches/double-chance-picks-tuesday-19-september-2017/

Double Chance Picks *** Tuesday *** 19 September 2017

DOUBLE CHANCE PICKS To return: ??? USD Odds: 1.95 Stake: 100 USD   Starting in   Teams   Our Prediction Odds Bournemouth - Brighton Soccer: England - Carabao Cup 1X 1.20 Wolfsburg - SV Werder Bremen Soccer: Germany…




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Hessian quotient equations on exterior domains. (arXiv:2004.06908v2 [math.AP] UPDATED)

It is well-known that a celebrated J"{o}rgens-Calabi-Pogorelov theorem for Monge-Amp`ere equations states that any classical (viscosity) convex solution of $det(D^2u)=1$ in $mathbb{R}^n$ must be a quadratic polynomial. Therefore, it is an interesting topic to study the existence and uniqueness theorem of such fully nonlinear partial differential equations' Dirichlet problems on exterior domains with suitable asymptotic conditions at infinity. As a continuation of the works of Caffarelli-Li for Monge-Amp`ere equation and of Bao-Li-Li for $k$-Hessian equations, this paper is devoted to the solvability of the exterior Dirichlet problem of Hessian quotient equations $sigma_k(lambda(D^2u))/sigma_l(lambda(D^2u))=1$ for any $1leq l<kleq n$ in all dimensions $ngeq 2$. By introducing the concept of generalized symmetric subsolutions and then using the Perron's method, we establish the existence theorem for viscosity solutions, with prescribed asymptotic behavior which is close to some quadratic polynomial at infinity.




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$L^p$-regularity of the Bergman projection on quotient domains. (arXiv:2004.02598v2 [math.CV] UPDATED)

We relate the $L^p$-mapping properties of the Bergman projections on two domains in $mathbb{C}^n$, one of which is the quotient of the other under the action of a finite group of biholomorphic automorphisms. We use this relation to deduce the sharp ranges of $L^p$-boundedness of the Bergman projection on certain $n$-dimensional model domains generalizing the Hartogs triangle.




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Eigenvalues of the Finsler $p$-Laplacian on varying domains. (arXiv:1912.00152v4 [math.AP] UPDATED)

We study the dependence of the first eigenvalue of the Finsler $p$-Laplacian and the corresponding eigenfunctions upon perturbation of the domain and we generalize a few results known for the standard $p$-Laplacian. In particular, we prove a Frech'{e}t differentiability result for the eigenvalues, we compute the corresponding Hadamard formulas and we prove a continuity result for the eigenfunctions. Finally, we briefly discuss a well-known overdetermined problem and we show how to deduce the Rellich-Pohozaev identity for the Finsler $p$-Laplacian from the Hadamard formula.




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Unbounded Kobayashi hyperbolic domains in $mathbb C^n$. (arXiv:1911.05632v2 [math.CV] UPDATED)

We first give a sufficient condition, issued from pluripotential theory, for an unbounded domain in the complex Euclidean space $mathbb C^n$ to be Kobayashi hyperbolic. Then, we construct an example of a rigid pseudoconvex domain in $mathbb C^3$ that is Kobayashi hyperbolic and has a nonempty core. In particular, this domain is not biholomorphic to a bounded domain in $mathbb C^3$ and the mentioned above sufficient condition for Kobayashi hyperbolicity is not necessary.




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Study of fractional Poincar'e inequalities on unbounded domains. (arXiv:1904.07170v2 [math.AP] UPDATED)

The central aim of this paper is to study (regional) fractional Poincar'e type inequalities on unbounded domains satisfying the finite ball condition. Both existence and non existence type results are established depending on various conditions on domains and on the range of $s in (0,1)$. The best constant in both regional fractional and fractional Poincar'e inequality is characterized for strip like domains $(omega imes mathbb{R}^{n-1})$, and the results obtained in this direction are analogous to those of the local case. This settles one of the natural questions raised by K. Yeressian in [ extit{Asymptotic behavior of elliptic nonlocal equations set in cylinders, Asymptot. Anal. 89, (2014), no 1-2}].




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Surjective endomorphisms of projective surfaces -- the existence of infinitely many dense orbits. (arXiv:2005.03628v1 [math.AG])

Let $f colon X o X$ be a surjective endomorphism of a normal projective surface. When $operatorname{deg} f geq 2$, applying an (iteration of) $f$-equivariant minimal model program (EMMP), we determine the geometric structure of $X$. Using this, we extend the second author's result to singular surfaces to the extent that either $X$ has an $f$-invariant non-constant rational function, or $f$ has infinitely many Zariski-dense forward orbits; this result is also extended to Adelic topology (which is finer than Zariski topology).




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A reaction-diffusion system to better comprehend the unlockdown: Application of SEIR-type model with diffusion to the spatial spread of COVID-19 in France. (arXiv:2005.03499v1 [q-bio.PE])

A reaction-diffusion model was developed describing the spread of the COVID-19 virus considering the mean daily movement of susceptible, exposed and asymptomatic individuals. The model was calibrated using data on the confirmed infection and death from France as well as their initial spatial distribution. First, the system of partial differential equations is studied, then the basic reproduction number, R0 is derived. Second, numerical simulations, based on a combination of level-set and finite differences, shown the spatial spread of COVID-19 from March 16 to June 16. Finally, scenarios of unlockdown are compared according to variation of distancing, or partially spatial lockdown.




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Solving equations in dense Sidon sets. (arXiv:2005.03484v1 [math.CO])

We offer an alternative proof of a result of Conlon, Fox, Sudakov and Zhao on solving translation-invariant linear equations in dense Sidon sets. Our proof generalises to equations in more than five variables and yields effective bounds.




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Removable singularities for Lipschitz caloric functions in time varying domains. (arXiv:2005.03397v1 [math.CA])

In this paper we study removable singularities for regular $(1,1/2)$-Lipschitz solutions of the heat equation in time varying domains. We introduce an associated Lipschitz caloric capacity and we study its metric and geometric properties and the connection with the $L^2$ boundedness of the singular integral whose kernel is given by the gradient of the fundamental solution of the heat equation.




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Maximum of Exponential Random Variables, Hurwitz's Zeta Function, and the Partition Function. (arXiv:2005.03392v1 [math.PR])

A natural problem in the context of the coupon collector's problem is the behavior of the maximum of independent geometrically distributed random variables (with distinct parameters). This question has been addressed by Brennan et al. (British J. of Math. & CS. 8 (2015), 330-336). Here we provide explicit asymptotic expressions for the moments of that maximum, as well as of the maximum of exponential random variables with corresponding parameters. We also deal with the probability of each of the variables being the maximal one.

The calculations lead to expressions involving Hurwitz's zeta function at certain special points. We find here explicitly the values of the function at these points. Also, the distribution function of the maximum we deal with is closely related to the generating function of the partition function. Thus, our results (and proofs) rely on classical results pertaining to the partition function.




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A Schur-Nevanlinna type algorithm for the truncated matricial Hausdorff moment problem. (arXiv:2005.03365v1 [math.CA])

The main goal of this paper is to achieve a parametrization of the solution set of the truncated matricial Hausdorff moment problem in the non-degenerate and degenerate situation. We treat the even and the odd cases simultaneously. Our approach is based on Schur analysis methods. More precisely, we use two interrelated versions of Schur-type algorithms, namely an algebraic one and a function-theoretic one. The algebraic version, worked out in our former paper arXiv:1908.05115, is an algorithm which is applied to finite or infinite sequences of complex matrices. The construction and discussion of the function-theoretic version is a central theme of this paper. This leads us to a complete description via Stieltjes transform of the solution set of the moment problem under consideration. Furthermore, we discuss special solutions in detail.




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Asymptotics of PDE in random environment by paracontrolled calculus. (arXiv:2005.03326v1 [math.PR])

We apply the paracontrolled calculus to study the asymptotic behavior of a certain quasilinear PDE with smeared mild noise, which originally appears as the space-time scaling limit of a particle system in random environment on one dimensional discrete lattice. We establish the convergence result and show a local in time well-posedness of the limit stochastic PDE with spatial white noise. It turns out that our limit stochastic PDE does not require any renormalization. We also show a comparison theorem for the limit equation.




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Lorentz estimates for quasi-linear elliptic double obstacle problems involving a Schr"odinger term. (arXiv:2005.03281v1 [math.AP])

Our goal in this article is to study the global Lorentz estimates for gradient of weak solutions to $p$-Laplace double obstacle problems involving the Schr"odinger term: $-Delta_p u + mathbb{V}|u|^{p-2}u$ with bound constraints $psi_1 le u le psi_2$ in non-smooth domains. This problem has its own interest in mathematics, engineering, physics and other branches of science. Our approach makes a novel connection between the study of Calder'on-Zygmund theory for nonlinear Schr"odinger type equations and variational inequalities for double obstacle problems.




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An Issue Raised in 1978 by a Then-Future Editor-in-Chief of the Journal "Order": Does the Endomorphism Poset of a Finite Connected Poset Tell Us That the Poset Is Connected?. (arXiv:2005.03255v1 [math.CO])

In 1978, Dwight Duffus---editor-in-chief of the journal "Order" from 2010 to 2018 and chair of the Mathematics Department at Emory University from 1991 to 2005---wrote that "it is not obvious that $P$ is connected and $P^P$ isomorphic to $Q^Q$ implies that $Q$ is connected," where $P$ and $Q$ are finite non-empty posets. We show that, indeed, under these hypotheses $Q$ is connected and $Pcong Q$.




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On the Boundary Harnack Principle in Holder domains. (arXiv:2005.03079v1 [math.AP])

We investigate the Boundary Harnack Principle in H"older domains of exponent $alpha>0$ by the analytical method developed in our previous work "A short proof of Boundary Harnack Principle".




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On the list recoverability of randomly punctured codes. (arXiv:2005.02478v2 [math.CO] UPDATED)

We show that a random puncturing of a code with good distance is list recoverable beyond the Johnson bound. In particular, this implies that there are Reed-Solomon codes that are list recoverable beyond the Johnson bound. It was previously known that there are Reed-Solomon codes that do not have this property. As an immediate corollary to our main theorem, we obtain better degree bounds on unbalanced expanders that come from Reed-Solomon codes.




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SPECTER: Document-level Representation Learning using Citation-informed Transformers. (arXiv:2004.07180v3 [cs.CL] UPDATED)

Representation learning is a critical ingredient for natural language processing systems. Recent Transformer language models like BERT learn powerful textual representations, but these models are targeted towards token- and sentence-level training objectives and do not leverage information on inter-document relatedness, which limits their document-level representation power. For applications on scientific documents, such as classification and recommendation, the embeddings power strong performance on end tasks. We propose SPECTER, a new method to generate document-level embedding of scientific documents based on pretraining a Transformer language model on a powerful signal of document-level relatedness: the citation graph. Unlike existing pretrained language models, SPECTER can be easily applied to downstream applications without task-specific fine-tuning. Additionally, to encourage further research on document-level models, we introduce SciDocs, a new evaluation benchmark consisting of seven document-level tasks ranging from citation prediction, to document classification and recommendation. We show that SPECTER outperforms a variety of competitive baselines on the benchmark.




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Unsupervised Domain Adaptation on Reading Comprehension. (arXiv:1911.06137v4 [cs.CL] UPDATED)

Reading comprehension (RC) has been studied in a variety of datasets with the boosted performance brought by deep neural networks. However, the generalization capability of these models across different domains remains unclear. To alleviate this issue, we are going to investigate unsupervised domain adaptation on RC, wherein a model is trained on labeled source domain and to be applied to the target domain with only unlabeled samples. We first show that even with the powerful BERT contextual representation, the performance is still unsatisfactory when the model trained on one dataset is directly applied to another target dataset. To solve this, we provide a novel conditional adversarial self-training method (CASe). Specifically, our approach leverages a BERT model fine-tuned on the source dataset along with the confidence filtering to generate reliable pseudo-labeled samples in the target domain for self-training. On the other hand, it further reduces domain distribution discrepancy through conditional adversarial learning across domains. Extensive experiments show our approach achieves comparable accuracy to supervised models on multiple large-scale benchmark datasets.




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Box Covers and Domain Orderings for Beyond Worst-Case Join Processing. (arXiv:1909.12102v2 [cs.DB] UPDATED)

Recent beyond worst-case optimal join algorithms Minesweeper and its generalization Tetris have brought the theory of indexing and join processing together by developing a geometric framework for joins. These algorithms take as input an index $mathcal{B}$, referred to as a box cover, that stores output gaps that can be inferred from traditional indexes, such as B+ trees or tries, on the input relations. The performances of these algorithms highly depend on the certificate of $mathcal{B}$, which is the smallest subset of gaps in $mathcal{B}$ whose union covers all of the gaps in the output space of a query $Q$. We study how to generate box covers that contain small size certificates to guarantee efficient runtimes for these algorithms. First, given a query $Q$ over a set of relations of size $N$ and a fixed set of domain orderings for the attributes, we give a $ ilde{O}(N)$-time algorithm called GAMB which generates a box cover for $Q$ that is guaranteed to contain the smallest size certificate across any box cover for $Q$. Second, we show that finding a domain ordering to minimize the box cover size and certificate is NP-hard through a reduction from the 2 consecutive block minimization problem on boolean matrices. Our third contribution is a $ ilde{O}(N)$-time approximation algorithm called ADORA to compute domain orderings, under which one can compute a box cover of size $ ilde{O}(K^r)$, where $K$ is the minimum box cover for $Q$ under any domain ordering and $r$ is the maximum arity of any relation. This guarantees certificates of size $ ilde{O}(K^r)$. We combine ADORA and GAMB with Tetris to form a new algorithm we call TetrisReordered, which provides several new beyond worst-case bounds. On infinite families of queries, TetrisReordered's runtimes are unboundedly better than the bounds stated in prior work.




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On Exposure Bias, Hallucination and Domain Shift in Neural Machine Translation. (arXiv:2005.03642v1 [cs.CL])

The standard training algorithm in neural machine translation (NMT) suffers from exposure bias, and alternative algorithms have been proposed to mitigate this. However, the practical impact of exposure bias is under debate. In this paper, we link exposure bias to another well-known problem in NMT, namely the tendency to generate hallucinations under domain shift. In experiments on three datasets with multiple test domains, we show that exposure bias is partially to blame for hallucinations, and that training with Minimum Risk Training, which avoids exposure bias, can mitigate this. Our analysis explains why exposure bias is more problematic under domain shift, and also links exposure bias to the beam search problem, i.e. performance deterioration with increasing beam size. Our results provide a new justification for methods that reduce exposure bias: even if they do not increase performance on in-domain test sets, they can increase model robustness to domain shift.




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Universal Coding and Prediction on Martin-L"of Random Points. (arXiv:2005.03627v1 [math.PR])

We perform an effectivization of classical results concerning universal coding and prediction for stationary ergodic processes over an arbitrary finite alphabet. That is, we lift the well-known almost sure statements to statements about Martin-L"of random sequences. Most of this work is quite mechanical but, by the way, we complete a result of Ryabko from 2008 by showing that each universal probability measure in the sense of universal coding induces a universal predictor in the prequential sense. Surprisingly, the effectivization of this implication holds true provided the universal measure does not ascribe too low conditional probabilities to individual symbols. As an example, we show that the Prediction by Partial Matching (PPM) measure satisfies this requirement. In the almost sure setting, the requirement is superfluous.




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Computing with bricks and mortar: Classification of waveforms with a doped concrete blocks. (arXiv:2005.03498v1 [cs.ET])

We present results showing the capability of concrete-based information processing substrate in the signal classification task in accordance with in materio computing paradigm. As the Reservoir Computing is a suitable model for describing embedded in materio computation, we propose that this type of presented basic construction unit can be used as a source for "reservoir of states" necessary for simple tuning of the readout layer. In that perspective, buildings constructed from computing concrete could function as a highly parallel information processor for smart architecture. We present an electrical characterization of the set of samples with different additive concentrations followed by a dynamical analysis of selected specimens showing fingerprints of memfractive properties. Moreover, on the basis of obtained parameters, classification of the signal waveform shapes can be performed in scenarios explicitly tuned for a given device terminal.




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A LiDAR-based real-time capable 3D Perception System for Automated Driving in Urban Domains. (arXiv:2005.03404v1 [cs.RO])

We present a LiDAR-based and real-time capable 3D perception system for automated driving in urban domains. The hierarchical system design is able to model stationary and movable parts of the environment simultaneously and under real-time conditions. Our approach extends the state of the art by innovative in-detail enhancements for perceiving road users and drivable corridors even in case of non-flat ground surfaces and overhanging or protruding elements. We describe a runtime-efficient pointcloud processing pipeline, consisting of adaptive ground surface estimation, 3D clustering and motion classification stages. Based on the pipeline's output, the stationary environment is represented in a multi-feature mapping and fusion approach. Movable elements are represented in an object tracking system capable of using multiple reference points to account for viewpoint changes. We further enhance the tracking system by explicit consideration of occlusion and ambiguity cases. Our system is evaluated using a subset of the TUBS Road User Dataset. We enhance common performance metrics by considering application-driven aspects of real-world traffic scenarios. The perception system shows impressive results and is able to cope with the addressed scenarios while still preserving real-time capability.




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Does Multi-Encoder Help? A Case Study on Context-Aware Neural Machine Translation. (arXiv:2005.03393v1 [cs.CL])

In encoder-decoder neural models, multiple encoders are in general used to represent the contextual information in addition to the individual sentence. In this paper, we investigate multi-encoder approaches in documentlevel neural machine translation (NMT). Surprisingly, we find that the context encoder does not only encode the surrounding sentences but also behaves as a noise generator. This makes us rethink the real benefits of multi-encoder in context-aware translation - some of the improvements come from robust training. We compare several methods that introduce noise and/or well-tuned dropout setup into the training of these encoders. Experimental results show that noisy training plays an important role in multi-encoder-based NMT, especially when the training data is small. Also, we establish a new state-of-the-art on IWSLT Fr-En task by careful use of noise generation and dropout methods.




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WSMN: An optimized multipurpose blind watermarking in Shearlet domain using MLP and NSGA-II. (arXiv:2005.03382v1 [cs.CR])

Digital watermarking is a remarkable issue in the field of information security to avoid the misuse of images in multimedia networks. Although access to unauthorized persons can be prevented through cryptography, it cannot be simultaneously used for copyright protection or content authentication with the preservation of image integrity. Hence, this paper presents an optimized multipurpose blind watermarking in Shearlet domain with the help of smart algorithms including MLP and NSGA-II. In this method, four copies of the robust copyright logo are embedded in the approximate coefficients of Shearlet by using an effective quantization technique. Furthermore, an embedded random sequence as a semi-fragile authentication mark is effectively extracted from details by the neural network. Due to performing an effective optimization algorithm for selecting optimum embedding thresholds, and also distinguishing the texture of blocks, the imperceptibility and robustness have been preserved. The experimental results reveal the superiority of the scheme with regard to the quality of watermarked images and robustness against hybrid attacks over other state-of-the-art schemes. The average PSNR and SSIM of the dual watermarked images are 38 dB and 0.95, respectively; Besides, it can effectively extract the copyright logo and locates forgery regions under severe attacks with satisfactory accuracy.




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Soft Interference Cancellation for Random Coding in Massive Gaussian Multiple-Access. (arXiv:2005.03364v1 [cs.IT])

We utilize recent results on the exact block error probability of Gaussian random codes in additive white Gaussian noise to analyze Gaussian random coding for massive multiple-access at finite message length. Soft iterative interference cancellation is found to closely approach the performance bounds recently found in [1]. The existence of two fundamentally different regimes in the trade-off between power and bandwidth efficiency reported in [2] is related to much older results in [3] on power optimization by linear programming. Furthermore, we tighten the achievability bounds of [1] in the low power regime and show that orthogonal constellations are very close to the theoretical limits for message lengths around 100 and above.




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Quantum correlation alignment for unsupervised domain adaptation. (arXiv:2005.03355v1 [quant-ph])

Correlation alignment (CORAL), a representative domain adaptation (DA) algorithm, decorrelates and aligns a labelled source domain dataset to an unlabelled target domain dataset to minimize the domain shift such that a classifier can be applied to predict the target domain labels. In this paper, we implement the CORAL on quantum devices by two different methods. One method utilizes quantum basic linear algebra subroutines (QBLAS) to implement the CORAL with exponential speedup in the number and dimension of the given data samples. The other method is achieved through a variational hybrid quantum-classical procedure. In addition, the numerical experiments of the CORAL with three different types of data sets, namely the synthetic data, the synthetic-Iris data, the handwritten digit data, are presented to evaluate the performance of our work. The simulation results prove that the variational quantum correlation alignment algorithm (VQCORAL) can achieve competitive performance compared with the classical CORAL.




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RNN-T Models Fail to Generalize to Out-of-Domain Audio: Causes and Solutions. (arXiv:2005.03271v1 [eess.AS])

In recent years, all-neural end-to-end approaches have obtained state-of-the-art results on several challenging automatic speech recognition (ASR) tasks. However, most existing works focus on building ASR models where train and test data are drawn from the same domain. This results in poor generalization characteristics on mismatched-domains: e.g., end-to-end models trained on short segments perform poorly when evaluated on longer utterances. In this work, we analyze the generalization properties of streaming and non-streaming recurrent neural network transducer (RNN-T) based end-to-end models in order to identify model components that negatively affect generalization performance. We propose two solutions: combining multiple regularization techniques during training, and using dynamic overlapping inference. On a long-form YouTube test set, when the non-streaming RNN-T model is trained with shorter segments of data, the proposed combination improves word error rate (WER) from 22.3% to 14.8%; when the streaming RNN-T model trained on short Search queries, the proposed techniques improve WER on the YouTube set from 67.0% to 25.3%. Finally, when trained on Librispeech, we find that dynamic overlapping inference improves WER on YouTube from 99.8% to 33.0%.




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Phase retrieval of complex-valued objects via a randomized Kaczmarz method. (arXiv:2005.03238v1 [cs.IT])

This paper investigates the convergence of the randomized Kaczmarz algorithm for the problem of phase retrieval of complex-valued objects. While this algorithm has been studied for the real-valued case}, its generalization to the complex-valued case is nontrivial and has been left as a conjecture. This paper establishes the connection between the convergence of the algorithm and the convexity of an objective function. Based on the connection, it demonstrates that when the sensing vectors are sampled uniformly from a unit sphere and the number of sensing vectors $m$ satisfies $m>O(nlog n)$ as $n, m ightarrowinfty$, then this algorithm with a good initialization achieves linear convergence to the solution with high probability.




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Constructing Accurate and Efficient Deep Spiking Neural Networks with Double-threshold and Augmented Schemes. (arXiv:2005.03231v1 [cs.NE])

Spiking neural networks (SNNs) are considered as a potential candidate to overcome current challenges such as the high-power consumption encountered by artificial neural networks (ANNs), however there is still a gap between them with respect to the recognition accuracy on practical tasks. A conversion strategy was thus introduced recently to bridge this gap by mapping a trained ANN to an SNN. However, it is still unclear that to what extent this obtained SNN can benefit both the accuracy advantage from ANN and high efficiency from the spike-based paradigm of computation. In this paper, we propose two new conversion methods, namely TerMapping and AugMapping. The TerMapping is a straightforward extension of a typical threshold-balancing method with a double-threshold scheme, while the AugMapping additionally incorporates a new scheme of augmented spike that employs a spike coefficient to carry the number of typical all-or-nothing spikes occurring at a time step. We examine the performance of our methods based on MNIST, Fashion-MNIST and CIFAR10 datasets. The results show that the proposed double-threshold scheme can effectively improve accuracies of the converted SNNs. More importantly, the proposed AugMapping is more advantageous for constructing accurate, fast and efficient deep SNNs as compared to other state-of-the-art approaches. Our study therefore provides new approaches for further integration of advanced techniques in ANNs to improve the performance of SNNs, which could be of great merit to applied developments with spike-based neuromorphic computing.




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End-to-End Domain Adaptive Attention Network for Cross-Domain Person Re-Identification. (arXiv:2005.03222v1 [cs.CV])

Person re-identification (re-ID) remains challenging in a real-world scenario, as it requires a trained network to generalise to totally unseen target data in the presence of variations across domains. Recently, generative adversarial models have been widely adopted to enhance the diversity of training data. These approaches, however, often fail to generalise to other domains, as existing generative person re-identification models have a disconnect between the generative component and the discriminative feature learning stage. To address the on-going challenges regarding model generalisation, we propose an end-to-end domain adaptive attention network to jointly translate images between domains and learn discriminative re-id features in a single framework. To address the domain gap challenge, we introduce an attention module for image translation from source to target domains without affecting the identity of a person. More specifically, attention is directed to the background instead of the entire image of the person, ensuring identifying characteristics of the subject are preserved. The proposed joint learning network results in a significant performance improvement over state-of-the-art methods on several benchmark datasets.




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A Stochastic Geometry Approach to Doppler Characterization in a LEO Satellite Network. (arXiv:2005.03205v1 [cs.IT])

A Non-terrestrial Network (NTN) comprising Low Earth Orbit (LEO) satellites can enable connectivity to underserved areas, thus complementing existing telecom networks. The high-speed satellite motion poses several challenges at the physical layer such as large Doppler frequency shifts. In this paper, an analytical framework is developed for statistical characterization of Doppler shift in an NTN where LEO satellites provide communication services to terrestrial users. Using tools from stochastic geometry, the users within a cell are grouped into disjoint clusters to limit the differential Doppler across users. Under some simplifying assumptions, the cumulative distribution function (CDF) and the probability density function are derived for the Doppler shift magnitude at a random user within a cluster. The CDFs are also provided for the minimum and the maximum Doppler shift magnitude within a cluster. Leveraging the analytical results, the interplay between key system parameters such as the cluster size and satellite altitude is examined. Numerical results validate the insights obtained from the analysis.




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Determinantal Point Processes in Randomized Numerical Linear Algebra. (arXiv:2005.03185v1 [cs.DS])

Randomized Numerical Linear Algebra (RandNLA) uses randomness to develop improved algorithms for matrix problems that arise in scientific computing, data science, machine learning, etc. Determinantal Point Processes (DPPs), a seemingly unrelated topic in pure and applied mathematics, is a class of stochastic point processes with probability distribution characterized by sub-determinants of a kernel matrix. Recent work has uncovered deep and fruitful connections between DPPs and RandNLA which lead to new guarantees and improved algorithms that are of interest to both areas. We provide an overview of this exciting new line of research, including brief introductions to RandNLA and DPPs, as well as applications of DPPs to classical linear algebra tasks such as least squares regression, low-rank approximation and the Nystr"om method. For example, random sampling with a DPP leads to new kinds of unbiased estimators for least squares, enabling more refined statistical and inferential understanding of these algorithms; a DPP is, in some sense, an optimal randomized algorithm for the Nystr"om method; and a RandNLA technique called leverage score sampling can be derived as the marginal distribution of a DPP. We also discuss recent algorithmic developments, illustrating that, while not quite as efficient as standard RandNLA techniques, DPP-based algorithms are only moderately more expensive.




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Unsupervised Multimodal Neural Machine Translation with Pseudo Visual Pivoting. (arXiv:2005.03119v1 [cs.CL])

Unsupervised machine translation (MT) has recently achieved impressive results with monolingual corpora only. However, it is still challenging to associate source-target sentences in the latent space. As people speak different languages biologically share similar visual systems, the potential of achieving better alignment through visual content is promising yet under-explored in unsupervised multimodal MT (MMT). In this paper, we investigate how to utilize visual content for disambiguation and promoting latent space alignment in unsupervised MMT. Our model employs multimodal back-translation and features pseudo visual pivoting in which we learn a shared multilingual visual-semantic embedding space and incorporate visually-pivoted captioning as additional weak supervision. The experimental results on the widely used Multi30K dataset show that the proposed model significantly improves over the state-of-the-art methods and generalizes well when the images are not available at the testing time.




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Football High: Helmets Do Not Prevent Concussions

Despite the improvements in helmet technology, helmets may prevent skull fractures, but they do not prevent concussions.




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How Does the IMPACT Baseline Test for Athletes Really Work?

Retired Soccer Star Briana Scurry describes how the computerized baseline test works and how it is used for athletes who have sustained a concussion.




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The Doctor Who Finally Said He Could Help

Retired soccer star Briana Scurry talks about finally finding hope and help after almost three years of being told she wouldn't get any better.