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Photography Life makes all their paid premium courses free

Photography Life has just contributed to the selection of online courses that you can take for free. While their premim courses are normally paid $150 per course, you can now access them free of charge. The founders have released them on YouTube, available for everyone to watch. The Photography Life team came to the decision […]

The post Photography Life makes all their paid premium courses free appeared first on DIY Photography.




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The Visual Evolution of the “Flattening the Curve” Information Graphic

Communication has been quite a challenge during the COVID-19 pandemic, and data visualization hasn't been the most helpful given the low quality of the data – see Amanda Makulec's plea to think harder about making another coronavirus chart. A great example of how to do things right is the widely-circulated Flatten the Curve information graphic/cartoon. […]




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Regular Tur'an numbers of complete bipartite graphs. (arXiv:2005.02907v2 [math.CO] UPDATED)

Let $mathrm{rex}(n, F)$ denote the maximum number of edges in an $n$-vertex graph that is regular and does not contain $F$ as a subgraph. We give lower bounds on $mathrm{rex}(n, F)$, that are best possible up to a constant factor, when $F$ is one of $C_4$, $K_{2,t}$, $K_{3,3}$ or $K_{s,t}$ when $t>s!$.




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Cameron-Liebler sets in Hamming graphs. (arXiv:2005.02227v2 [math.CO] UPDATED)

In this paper, we discuss Cameron-Liebler sets in Hamming graphs, obtain several equivalent definitions and present all classification results.




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Triangles in graphs without bipartite suspensions. (arXiv:2004.11930v2 [math.CO] UPDATED)

Given graphs $T$ and $H$, the generalized Tur'an number ex$(n,T,H)$ is the maximum number of copies of $T$ in an $n$-vertex graph with no copies of $H$. Alon and Shikhelman, using a result of ErdH os, determined the asymptotics of ex$(n,K_3,H)$ when the chromatic number of $H$ is greater than 3 and proved several results when $H$ is bipartite. We consider this problem when $H$ has chromatic number 3. Even this special case for the following relatively simple 3-chromatic graphs appears to be challenging.

The suspension $widehat H$ of a graph $H$ is the graph obtained from $H$ by adding a new vertex adjacent to all vertices of $H$. We give new upper and lower bounds on ex$(n,K_3,widehat{H})$ when $H$ is a path, even cycle, or complete bipartite graph. One of the main tools we use is the triangle removal lemma, but it is unclear if much stronger statements can be proved without using the removal lemma.




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On the Asymptotic $u_0$-Expected Flooding Time of Stationary Edge-Markovian Graphs. (arXiv:2004.03660v4 [math.PR] UPDATED)

Consider that $u_0$ nodes are aware of some piece of data $d_0$. This note derives the expected time required for the data $d_0$ to be disseminated through-out a network of $n$ nodes, when communication between nodes evolves according to a graphical Markov model $overline{ mathcal{G}}_{n,hat{p}}$ with probability parameter $hat{p}$. In this model, an edge between two nodes exists at discrete time $k in mathbb{N}^+$ with probability $hat{p}$ if this edge existed at $k-1$, and with probability $(1-hat{p})$ if this edge did not exist at $k-1$. Each edge is interpreted as a bidirectional communication link over which data between neighbors is shared. The initial communication graph is assumed to be an Erdos-Renyi random graph with parameters $(n,hat{p})$, hence we consider a emph{stationary} Markov model $overline{mathcal{G}}_{n,hat{p}}$. The asymptotic "$u_0$-expected flooding time" of $overline{mathcal{G}}_{n,hat{p}}$ is defined as the expected number of iterations required to transmit the data $d_0$ from $u_0$ nodes to $n$ nodes, in the limit as $n$ approaches infinity. Although most previous results on the asymptotic flooding time in graphical Markov models are either emph{almost sure} or emph{with high probability}, the bounds obtained here are emph{in expectation}. However, our bounds are tighter and can be more complete than previous results.




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Monochromatic Equilateral Triangles in the Unit Distance Graph. (arXiv:1909.09856v2 [math.CO] UPDATED)

Let $chi_{Delta}(mathbb{R}^{n})$ denote the minimum number of colors needed to color $mathbb{R}^{n}$ so that there will not be a monochromatic equilateral triangle with side length $1$. Using the slice rank method, we reprove a result of Frankl and Rodl, and show that $chi_{Delta}left(mathbb{R}^{n} ight)$ grows exponentially with $n$. This technique substantially improves upon the best known quantitative lower bounds for $chi_{Delta}left(mathbb{R}^{n} ight)$, and we obtain [ chi_{Delta}left(mathbb{R}^{n} ight)>(1.01446+o(1))^{n}. ]




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$k$-Critical Graphs in $P_5$-Free Graphs. (arXiv:2005.03441v1 [math.CO])

Given two graphs $H_1$ and $H_2$, a graph $G$ is $(H_1,H_2)$-free if it contains no induced subgraph isomorphic to $H_1$ or $H_2$. Let $P_t$ be the path on $t$ vertices. A graph $G$ is $k$-vertex-critical if $G$ has chromatic number $k$ but every proper induced subgraph of $G$ has chromatic number less than $k$. The study of $k$-vertex-critical graphs for graph classes is an important topic in algorithmic graph theory because if the number of such graphs that are in a given hereditary graph class is finite, then there is a polynomial-time algorithm to decide if a graph in the class is $(k-1)$-colorable.

In this paper, we initiate a systematic study of the finiteness of $k$-vertex-critical graphs in subclasses of $P_5$-free graphs. Our main result is a complete classification of the finiteness of $k$-vertex-critical graphs in the class of $(P_5,H)$-free graphs for all graphs $H$ on 4 vertices. To obtain the complete dichotomy, we prove the finiteness for four new graphs $H$ using various techniques -- such as Ramsey-type arguments and the dual of Dilworth's Theorem -- that may be of independent interest.




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Aspiration can promote cooperation in well-mixed populations as in regular graphs. (arXiv:2005.03421v1 [q-bio.PE])

Classical studies on aspiration-based dynamics suggest that a dissatisfied individual changes strategy without taking into account the success of others. This promotes defection spreading. The imitation-based dynamics allow individuals to imitate successful strategies without taking into account their own-satisfactions. In this article, we propose to study a dynamic based on aspiration which takes into account imitation of successful strategies for dissatisfied individuals. This helps cooperative members to resist. Individuals compare their success to their desired satisfaction level before making a decision to update their strategies. This mechanism helps individuals with a minimum of self-satisfaction to maintain their strategies. If an individual is dissatisfied, it will learn from others by choosing successful strategies. We derive an exact expression of the fixation probability in well-mixed populations as in structured populations in networks. As a result, we show that selection may favor cooperation more than defection in well-mixed populations as in populations ranged over a regular graph. We show that the best scenario is a graph with small connectivity.




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A note on Penner's cocycle on the fatgraph complex. (arXiv:2005.03414v1 [math.GT])

We study a 1-cocycle on the fatgraph complex of a punctured surface introduced by Penner. We present an explicit cobounding cochain for this cocycle, whose formula involves a summation over trivalent vertices of a trivalent fatgraph spine. In a similar fashion, we express the symplectic form of the underlying surface of a given fatgraph spine.




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Minimum pair degree condition for tight Hamiltonian cycles in $4$-uniform hypergraphs. (arXiv:2005.03391v1 [math.CO])

We show that every 4-uniform hypergraph with $n$ vertices and minimum pair degree at least $(5/9+o(1))n^2/2$ contains a tight Hamiltonian cycle. This degree condition is asymptotically optimal.




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Dynamical Phase Transitions for Fluxes of Mass on Finite Graphs. (arXiv:2005.03262v1 [cond-mat.stat-mech])

We study the time-averaged flux in a model of particles that randomly hop on a finite directed graph. In the limit as the number of particles and the time window go to infinity but the graph remains finite, the large-deviation rate functional of the average flux is given by a variational formulation involving paths of the density and flux. We give sufficient conditions under which the large deviations of a given time averaged flux is determined by paths that are constant in time. We then consider a class of models on a discrete ring for which it is possible to show that a better strategy is obtained producing a time-dependent path. This phenomenon, called a dynamical phase transition, is known to occur for some particle systems in the hydrodynamic scaling limit, which is thus extended to the setting of a finite graph.




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On the Gorenstein property of the Ehrhart ring of the stable set polytope of an h-perfect graph. (arXiv:2005.03259v1 [math.CO])

In this paper, we give a criterion of the Gorenstein property of the Ehrhart ring of the stable set polytope of an h-perfect graph: the Ehrhart ring of the stable set polytope of an h-perfect graph $G$ is Gorenstein if and only if (1) sizes of maximal cliques are constant (say $n$) and (2) (a) $n=1$, (b) $n=2$ and there is no odd cycle without chord and length at least 7 or (c) $ngeq 3$ and there is no odd cycle without chord and length at least 5.




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New constructions of strongly regular Cayley graphs on abelian groups. (arXiv:2005.03183v1 [math.CO])

In this paper, we give new constructions of strongly regular Cayley graphs on abelian groups as generalizations of a series of known constructions: the construction of covering extended building sets in finite fields by Xia (1992), the product construction of Menon-Hadamard difference sets by Turyn (1984), and the construction of Paley type partial difference sets by Polhill (2010). Then, we obtain new large families of strongly regular Cayley graphs of Latin square type or negative Latin square type.




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Sharp p-bounds for maximal operators on finite graphs. (arXiv:2005.03146v1 [math.CA])

Let $G=(V,E)$ be a finite graph and $M_G$ be the centered Hardy-Littlewood maximal operator defined there. We found the optimal value $C_{G,p}$ such that the inequality $$Var_{p}(M_{G}f)le C_{G,p}Var_{p}(f)$$ holds for every every $f:V o mathbb{R},$ where $Var_p$ stands for the $p$-variation, when: (i)$G=K_n$ (complete graph) and $pin [frac{ln(4)}{ln(6)},infty)$ or $G=K_4$ and $pin (0,infty)$;(ii) $G=S_n$(star graph) and $1ge pge frac{1}{2}$; $pin (0,frac{1}{2})$ and $nge C(p)<infty$ or $G=S_3$ and $pin (1,infty).$ We also found the optimal value $L_{G,2}$ such that the inequality $$|M_{G}f|_2le L_{G,2}|f|_2$$ holds for every $f:V o mathbb{R}$, when: (i)$G=K_n$ and $nge 3$;(ii)$G=S_n$ and $nge 3.$




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On planar graphs of uniform polynomial growth. (arXiv:2005.03139v1 [math.PR])

Consider an infinite planar graph with uniform polynomial growth of degree d > 2. Many examples of such graphs exhibit similar geometric and spectral properties, and it has been conjectured that this is necessary. We present a family of counterexamples. In particular, we show that for every rational d > 2, there is a planar graph with uniform polynomial growth of degree d on which the random walk is transient, disproving a conjecture of Benjamini (2011).

By a well-known theorem of Benjamini and Schramm, such a graph cannot be a unimodular random graph. We also give examples of unimodular random planar graphs of uniform polynomial growth with unexpected properties. For instance, graphs of (almost sure) uniform polynomial growth of every rational degree d > 2 for which the speed exponent of the walk is larger than 1/d, and in which the complements of all balls are connected. This resolves negatively two questions of Benjamini and Papasoglou (2011).




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GraphBLAST: A High-Performance Linear Algebra-based Graph Framework on the GPU. (arXiv:1908.01407v3 [cs.DC] CROSS LISTED)

High-performance implementations of graph algorithms are challenging to implement on new parallel hardware such as GPUs, because of three challenges: (1) difficulty of coming up with graph building blocks, (2) load imbalance on parallel hardware, and (3) graph problems having low arithmetic intensity. To address these challenges, GraphBLAS is an innovative, on-going effort by the graph analytics community to propose building blocks based in sparse linear algebra, which will allow graph algorithms to be expressed in a performant, succinct, composable and portable manner. In this paper, we examine the performance challenges of a linear algebra-based approach to building graph frameworks and describe new design principles for overcoming these bottlenecks. Among the new design principles is exploiting input sparsity, which allows users to write graph algorithms without specifying push and pull direction. Exploiting output sparsity allows users to tell the backend which values of the output in a single vectorized computation they do not want computed. Load-balancing is an important feature for balancing work amongst parallel workers. We describe the important load-balancing features for handling graphs with different characteristics. The design principles described in this paper have been implemented in "GraphBLAST", the first open-source linear algebra-based graph framework on GPU targeting high-performance computing. The results show that on a single GPU, GraphBLAST has on average at least an order of magnitude speedup over previous GraphBLAS implementations SuiteSparse and GBTL, comparable performance to the fastest GPU hardwired primitives and shared-memory graph frameworks Ligra and Gunrock, and better performance than any other GPU graph framework, while offering a simpler and more concise programming model.




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Optimal Adjacent Vertex-Distinguishing Edge-Colorings of Circulant Graphs. (arXiv:2004.12822v2 [cs.DM] UPDATED)

A k-proper edge-coloring of a graph G is called adjacent vertex-distinguishing if any two adjacent vertices are distinguished by the set of colors appearing in the edges incident to each vertex. The smallest value k for which G admits such coloring is denoted by $chi$'a (G). We prove that $chi$'a (G) = 2R + 1 for most circulant graphs Cn([[1, R]]).




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Personal Health Knowledge Graphs for Patients. (arXiv:2004.00071v2 [cs.AI] UPDATED)

Existing patient data analytics platforms fail to incorporate information that has context, is personal, and topical to patients. For a recommendation system to give a suitable response to a query or to derive meaningful insights from patient data, it should consider personal information about the patient's health history, including but not limited to their preferences, locations, and life choices that are currently applicable to them. In this review paper, we critique existing literature in this space and also discuss the various research challenges that come with designing, building, and operationalizing a personal health knowledge graph (PHKG) for patients.




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Subgraph densities in a surface. (arXiv:2003.13777v2 [math.CO] UPDATED)

Given a fixed graph $H$ that embeds in a surface $Sigma$, what is the maximum number of copies of $H$ in an $n$-vertex graph $G$ that embeds in $Sigma$? We show that the answer is $Theta(n^{f(H)})$, where $f(H)$ is a graph invariant called the `flap-number' of $H$, which is independent of $Sigma$. This simultaneously answers two open problems posed by Eppstein (1993). When $H$ is a complete graph we give more precise answers.




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Eccentricity terrain of $delta$-hyperbolic graphs. (arXiv:2002.08495v2 [cs.DM] UPDATED)

A graph $G=(V,E)$ is $delta$-hyperbolic if for any four vertices $u,v,w,x$, the two larger of the three distance sums $d(u,v)+d(w,x)$, $d(u,w)+d(v,x)$, and $d(u,x)+d(v,w)$ differ by at most $2delta geq 0$. Recent work shows that many real-world graphs have small hyperbolicity $delta$. This paper describes the eccentricity terrain of a $delta$-hyperbolic graph. The eccentricity function $e_G(v)=max{d(v,u) : u in V}$ partitions the vertex set of $G$ into eccentricity layers $C_{k}(G) = {v in V : e(v)=rad(G)+k}$, $k in mathbb{N}$, where $rad(G)=min{e_G(v): vin V}$ is the radius of $G$. The paper studies the eccentricity layers of vertices along shortest paths, identifying such terrain features as hills, plains, valleys, terraces, and plateaus. It introduces the notion of $eta$-pseudoconvexity, which implies Gromov's $epsilon$-quasiconvexity, and illustrates the abundance of pseudoconvex sets in $delta$-hyperbolic graphs. In particular, it shows that all sets $C_{leq k}(G)={vin V : e_G(v) leq rad(G) + k}$, $kin mathbb{N}$, are $(2delta-1)$-pseudoconvex. Additionally, several bounds on the eccentricity of a vertex are obtained which yield a few approaches to efficiently approximating all eccentricities. An $O(delta |E|)$ time eccentricity approximation $hat{e}(v)$, for all $vin V$, is presented that uses distances to two mutually distant vertices and satisfies $e_G(v)-2delta leq hat{e}(v) leq {e_G}(v)$. It also shows existence of two eccentricity approximating spanning trees $T$, one constructible in $O(delta |E|)$ time and the other in $O(|E|)$ time, which satisfy ${e}_G(v) leq e_T(v) leq {e}_G(v)+4delta+1$ and ${e}_G(v) leq e_T(v) leq {e}_G(v)+6delta$, respectively. Thus, the eccentricity terrain of a tree gives a good approximation (up-to an additive error $O(delta))$ of the eccentricity terrain of a $delta$-hyperbolic graph.




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Measuring Social Bias in Knowledge Graph Embeddings. (arXiv:1912.02761v2 [cs.CL] UPDATED)

It has recently been shown that word embeddings encode social biases, with a harmful impact on downstream tasks. However, to this point there has been no similar work done in the field of graph embeddings. We present the first study on social bias in knowledge graph embeddings, and propose a new metric suitable for measuring such bias. We conduct experiments on Wikidata and Freebase, and show that, as with word embeddings, harmful social biases related to professions are encoded in the embeddings with respect to gender, religion, ethnicity and nationality. For example, graph embeddings encode the information that men are more likely to be bankers, and women more likely to be homekeepers. As graph embeddings become increasingly utilized, we suggest that it is important the existence of such biases are understood and steps taken to mitigate their impact.




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GeoLogic -- Graphical interactive theorem prover for Euclidean geometry. (arXiv:2005.03586v1 [cs.LO])

Domain of mathematical logic in computers is dominated by automated theorem provers (ATP) and interactive theorem provers (ITP). Both of these are hard to access by AI from the human-imitation approach: ATPs often use human-unfriendly logical foundations while ITPs are meant for formalizing existing proofs rather than problem solving. We aim to create a simple human-friendly logical system for mathematical problem solving. We picked the case study of Euclidean geometry as it can be easily visualized, has simple logic, and yet potentially offers many high-school problems of various difficulty levels. To make the environment user friendly, we abandoned strict logic required by ITPs, allowing to infer topological facts from pictures. We present our system for Euclidean geometry, together with a graphical application GeoLogic, similar to GeoGebra, which allows users to interactively study and prove properties about the geometrical setup.




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Faceted Search of Heterogeneous Geographic Information for Dynamic Map Projection. (arXiv:2005.03531v1 [cs.HC])

This paper proposes a faceted information exploration model that supports coarse-grained and fine-grained focusing of geographic maps by offering a graphical representation of data attributes within interactive widgets. The proposed approach enables (i) a multi-category projection of long-lasting geographic maps, based on the proposal of efficient facets for data exploration in sparse and noisy datasets, and (ii) an interactive representation of the search context based on widgets that support data visualization, faceted exploration, category-based information hiding and transparency of results at the same time. The integration of our model with a semantic representation of geographical knowledge supports the exploration of information retrieved from heterogeneous data sources, such as Public Open Data and OpenStreetMap. We evaluated our model with users in the OnToMap collaborative Web GIS. The experimental results show that, when working on geographic maps populated with multiple data categories, it outperforms simple category-based map projection and traditional faceted search tools, such as checkboxes, in both user performance and experience.




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Linear Time LexDFS on Chordal Graphs. (arXiv:2005.03523v1 [cs.DM])

Lexicographic Depth First Search (LexDFS) is a special variant of a Depth First Search (DFS), which was introduced by Corneil and Krueger in 2008. While this search has been used in various applications, in contrast to other graph searches, no general linear time implementation is known to date. In 2014, K"ohler and Mouatadid achieved linear running time to compute some special LexDFS orders for cocomparability graphs. In this paper, we present a linear time implementation of LexDFS for chordal graphs. Our algorithm is able to find any LexDFS order for this graph class. To the best of our knowledge this is the first unrestricted linear time implementation of LexDFS on a non-trivial graph class. In the algorithm we use a search tree computed by Lexicographic Breadth First Search (LexBFS).




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Anonymized GCN: A Novel Robust Graph Embedding Method via Hiding Node Position in Noise. (arXiv:2005.03482v1 [cs.LG])

Graph convolution network (GCN) have achieved state-of-the-art performance in the task of node prediction in the graph structure. However, with the gradual various of graph attack methods, there are lack of research on the robustness of GCN. At this paper, we will design a robust GCN method for node prediction tasks. Considering the graph structure contains two types of information: node information and connection information, and attackers usually modify the connection information to complete the interference with the prediction results of the node, we first proposed a method to hide the connection information in the generator, named Anonymized GCN (AN-GCN). By hiding the connection information in the graph structure in the generator through adversarial training, the accurate node prediction can be completed only by the node number rather than its specific position in the graph. Specifically, we first demonstrated the key to determine the embedding of a specific node: the row corresponding to the node of the eigenmatrix of the Laplace matrix, by target it as the output of the generator, we designed a method to hide the node number in the noise. Take the corresponding noise as input, we will obtain the connection structure of the node instead of directly obtaining. Then the encoder and decoder are spliced both in discriminator, so that after adversarial training, the generator and discriminator can cooperate to complete the encoding and decoding of the graph, then complete the node prediction. Finally, All node positions can generated by noise at the same time, that is to say, the generator will hides all the connection information of the graph structure. The evaluation shows that we only need to obtain the initial features and node numbers of the nodes to complete the node prediction, and the accuracy did not decrease, but increased by 0.0293.




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Bundle Recommendation with Graph Convolutional Networks. (arXiv:2005.03475v1 [cs.IR])

Bundle recommendation aims to recommend a bundle of items for a user to consume as a whole. Existing solutions integrate user-item interaction modeling into bundle recommendation by sharing model parameters or learning in a multi-task manner, which cannot explicitly model the affiliation between items and bundles, and fail to explore the decision-making when a user chooses bundles. In this work, we propose a graph neural network model named BGCN (short for extit{ extBF{B}undle extBF{G}raph extBF{C}onvolutional extBF{N}etwork}) for bundle recommendation. BGCN unifies user-item interaction, user-bundle interaction and bundle-item affiliation into a heterogeneous graph. With item nodes as the bridge, graph convolutional propagation between user and bundle nodes makes the learned representations capture the item level semantics. Through training based on hard-negative sampler, the user's fine-grained preferences for similar bundles are further distinguished. Empirical results on two real-world datasets demonstrate the strong performance gains of BGCN, which outperforms the state-of-the-art baselines by 10.77\% to 23.18\%.




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Estimating Blood Pressure from Photoplethysmogram Signal and Demographic Features using Machine Learning Techniques. (arXiv:2005.03357v1 [eess.SP])

Hypertension is a potentially unsafe health ailment, which can be indicated directly from the Blood pressure (BP). Hypertension always leads to other health complications. Continuous monitoring of BP is very important; however, cuff-based BP measurements are discrete and uncomfortable to the user. To address this need, a cuff-less, continuous and a non-invasive BP measurement system is proposed using Photoplethysmogram (PPG) signal and demographic features using machine learning (ML) algorithms. PPG signals were acquired from 219 subjects, which undergo pre-processing and feature extraction steps. Time, frequency and time-frequency domain features were extracted from the PPG and their derivative signals. Feature selection techniques were used to reduce the computational complexity and to decrease the chance of over-fitting the ML algorithms. The features were then used to train and evaluate ML algorithms. The best regression models were selected for Systolic BP (SBP) and Diastolic BP (DBP) estimation individually. Gaussian Process Regression (GPR) along with ReliefF feature selection algorithm outperforms other algorithms in estimating SBP and DBP with a root-mean-square error (RMSE) of 6.74 and 3.59 respectively. This ML model can be implemented in hardware systems to continuously monitor BP and avoid any critical health conditions due to sudden changes.




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Interval type-2 fuzzy logic system based similarity evaluation for image steganography. (arXiv:2005.03310v1 [cs.MM])

Similarity measure, also called information measure, is a concept used to distinguish different objects. It has been studied from different contexts by employing mathematical, psychological, and fuzzy approaches. Image steganography is the art of hiding secret data into an image in such a way that it cannot be detected by an intruder. In image steganography, hiding secret data in the plain or non-edge regions of the image is significant due to the high similarity and redundancy of the pixels in their neighborhood. However, the similarity measure of the neighboring pixels, i.e., their proximity in color space, is perceptual rather than mathematical. This paper proposes an interval type 2 fuzzy logic system (IT2 FLS) to determine the similarity between the neighboring pixels by involving an instinctive human perception through a rule-based approach. The pixels of the image having high similarity values, calculated using the proposed IT2 FLS similarity measure, are selected for embedding via the least significant bit (LSB) method. We term the proposed procedure of steganography as IT2 FLS LSB method. Moreover, we have developed two more methods, namely, type 1 fuzzy logic system based least significant bits (T1FLS LSB) and Euclidean distance based similarity measures for least significant bit (SM LSB) steganographic methods. Experimental simulations were conducted for a collection of images and quality index metrics, such as PSNR, UQI, and SSIM are used. All the three steganographic methods are applied on datasets and the quality metrics are calculated. The obtained stego images and results are shown and thoroughly compared to determine the efficacy of the IT2 FLS LSB method. Finally, we have done a comparative analysis of the proposed approach with the existing well-known steganographic methods to show the effectiveness of our proposed steganographic method.




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Exploratory Analysis of Covid-19 Tweets using Topic Modeling, UMAP, and DiGraphs. (arXiv:2005.03082v1 [cs.SI])

This paper illustrates five different techniques to assess the distinctiveness of topics, key terms and features, speed of information dissemination, and network behaviors for Covid19 tweets. First, we use pattern matching and second, topic modeling through Latent Dirichlet Allocation (LDA) to generate twenty different topics that discuss case spread, healthcare workers, and personal protective equipment (PPE). One topic specific to U.S. cases would start to uptick immediately after live White House Coronavirus Task Force briefings, implying that many Twitter users are paying attention to government announcements. We contribute machine learning methods not previously reported in the Covid19 Twitter literature. This includes our third method, Uniform Manifold Approximation and Projection (UMAP), that identifies unique clustering-behavior of distinct topics to improve our understanding of important themes in the corpus and help assess the quality of generated topics. Fourth, we calculated retweeting times to understand how fast information about Covid19 propagates on Twitter. Our analysis indicates that the median retweeting time of Covid19 for a sample corpus in March 2020 was 2.87 hours, approximately 50 minutes faster than repostings from Chinese social media about H7N9 in March 2013. Lastly, we sought to understand retweet cascades, by visualizing the connections of users over time from fast to slow retweeting. As the time to retweet increases, the density of connections also increase where in our sample, we found distinct users dominating the attention of Covid19 retweeters. One of the simplest highlights of this analysis is that early-stage descriptive methods like regular expressions can successfully identify high-level themes which were consistently verified as important through every subsequent analysis.




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Evaluating text coherence based on the graph of the consistency of phrases to identify symptoms of schizophrenia. (arXiv:2005.03008v1 [cs.CL])

Different state-of-the-art methods of the detection of schizophrenia symptoms based on the estimation of text coherence have been analyzed. The analysis of a text at the level of phrases has been suggested. The method based on the graph of the consistency of phrases has been proposed to evaluate the semantic coherence and the cohesion of a text. The semantic coherence, cohesion, and other linguistic features (lexical diversity, lexical density) have been taken into account to form feature vectors for the training of a model-classifier. The training of the classifier has been performed on the set of English-language interviews. According to the retrieved results, the impact of each feature on the output of the model has been analyzed. The results obtained can indicate that the proposed method based on the graph of the consistency of phrases may be used in the different tasks of the detection of mental illness.




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24 Must-Know Graphic Design Terms

Graphic design is everywhere — it’s used in traditional marketing efforts like billboards and fliers, and more importantly, it’s used in nearly every single digital marketing initiative from web design to social media marketing. If you’re a business that’s working with a digital marketing agency for any number of marketing campaigns (especially web design), it’s […]

The post 24 Must-Know Graphic Design Terms appeared first on WebFX Blog.




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Psychology of Color [Infographic]

Perhaps no choice is as vital to marketing as color. Whether you are selecting the color for a product or for your email marketing campaign, color has a tremendous impact on all of us. Subconsciously, we associate different colors with different things. This infographic examines the psychology of color and looks at some common associations […]

The post Psychology of Color [Infographic] appeared first on WebFX Blog.




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Graphene prepared by using edge functionalization of graphite

Disclosed is a method for producing graphene functionalized at its edge positions of graphite. Organic material having one or more functional groups is reacted with graphite in reaction medium comprising methanesulfonic acid and phosphorus pentoxide, or in reaction medium comprising trifluoromethanesulfonic acid, to produce graphene having organic material fuctionalized at edges. And then, high purity and large scaled graphene and film can be obtained by dispersing, centrifugal separating the functionalized graphene in a solvent and reducing, in particular heat treating the graphene. According to the present invention graphene can be produced inexpensively in a large amount with a minimum loss of graphite. (FIG. 1)




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Wearable electromyography-based human-computer interface

A “Wearable Electromyography-Based Controller” includes a plurality of Electromyography (EMG) sensors and provides a wired or wireless human-computer interface (HCI) for interacting with computing systems and attached devices via electrical signals generated by specific movement of the user's muscles. Following initial automated self-calibration and positional localization processes, measurement and interpretation of muscle generated electrical signals is accomplished by sampling signals from the EMG sensors of the Wearable Electromyography-Based Controller. In operation, the Wearable Electromyography-Based Controller is donned by the user and placed into a coarsely approximate position on the surface of the user's skin. Automated cues or instructions are then provided to the user for fine-tuning placement of the Wearable Electromyography-Based Controller. Examples of Wearable Electromyography-Based Controllers include articles of manufacture, such as an armband, wristwatch, or article of clothing having a plurality of integrated EMG-based sensor nodes and associated electronics.




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Controlled synthesis of monolithically-integrated graphene structure

In a method for fabricating a graphene structure, there is formed on a fabrication substrate a pattern of a plurality of distinct graphene catalyst materials. In one graphene synthesis step, different numbers of graphene layers are formed on the catalyst materials in the formed pattern. In a method for fabricating a graphene transistor, on a fabrication substrate at least one graphene catalyst material is provided at a substrate region specified for synthesizing a graphene transistor channel and at least one graphene catalyst material is provided at a substrate region specified for synthesizing a graphene transistor source, and at a substrate region specified for synthesizing a graphene transistor drain. Then in one graphene synthesis step, at least one layer of graphene is formed at the substrate region for the graphene transistor channel, and at the regions for the transistor source and drain there are formed a plurality of layers of graphene.




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Method and apparatus for a geographically determined Jewish religious clock and electrical device combination with holiday and preference modes

An independently functioning or centrally controlled wall light switch is configured to operate in normal mode and a Jewish holiday mode wherein the state of the light is fixed, regardless of the user's physical manipulation of the light switch. The control system automatically activates holiday mode by combining a geographically determined Jewish religious clock executed by software and hardware that utilizes the current time, date and geographical location of the apparatus in accordance with the Jewish definition of time and laws for calculating numerous religiously significant shifting daily points in time. The control system further incorporates several energy saving and preference modes by utilizing a particular day's calculated religious points in time in conjunction with holiday behavior patterns common to most Jewish families to provide the user with a greatly simplified means of programming an automatically adjusting on/off light timer and dimming overlay functionality during holiday mode.




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Fluorographene and preparation method thereof

A fluorographene and preparation method thereof are provided. For the said fluorographene, the fraction of F is 0.5




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Foams of graphene, method of making and materials made thereof

Method for making a liquid foam from graphene. The method includes preparing an aqueous dispersion of graphene oxide and adding a water miscible compound to the aqueous dispersion to produce a mixture including a modified form of graphene oxide. A second immiscible fluid (a gas or a liquid) with or without a surfactant are added to the mixture and agitated to form a fluid/water composite wherein the modified form of graphene oxide aggregates at the interfaces between the fluid and water to form either a closed or open cell foam. The modified form of graphene oxide is the foaming agent.




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Applying coding standards in graphical programming environments

Graphical programming or modeling environments in which a coding standard can be applied to graphical programs or models are disclosed. The present invention provides mechanisms for applying the coding standard to graphical programs/models in the graphical programming/modeling environments. The mechanisms may detect violations of the coding standard in the graphical model and report such violations to the users. The mechanisms may automatically correct the graphical model to remove the violations from the graphical model. The mechanisms may also automatically avoid the violations in the simulation and/or code generation of the graphical model.




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Method and system for forming patterns with charged particle beam lithography

In a method for fracturing or mask data preparation or mask process correction for charged particle beam lithography, a plurality of shots are determined that will form a pattern on a surface, where shots are determined so as to reduce sensitivity of the resulting pattern to changes in beam blur (βf). In some embodiments, the sensitivity to changes in βf is reduced by varying the charged particle surface dosage for a portion of the pattern. Methods for forming patterns on a surface, and for manufacturing an integrated circuit are also disclosed, in which pattern sensitivity to changes in βf is reduced.




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Method and system for critical dimension uniformity using charged particle beam lithography

A method for mask data preparation or mask process correction is disclosed in which a set of charged particle beam shots is determined which is capable of forming a pattern on a surface, wherein critical dimension uniformity (CDU) of the pattern is optimized. In some embodiments the CDU is optimized by varying at least two factors. In other embodiments, model-based techniques are used. In yet other embodiments, the surface is a reticle to be used in an optical lithographic process to form a pattern on a wafer, and CDU on the wafer is optimized.




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Method and system for forming high accuracy patterns using charged particle beam lithography

A method and system for optical proximity correction (OPC) is disclosed in which a set of shaped beam shots is determined which, when used in a shaped beam charged particle beam writer, will form a pattern on a reticle, where some of the shots overlap, where the pattern on the reticle is an OPC-corrected version of an input pattern, and where the sensitivity of the pattern on the reticle to manufacturing variation is reduced. A method for fracturing or mask data preparation is also disclosed.




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Methods and apparatus to create process control graphics based on process control information

Methods and apparatus to automatically link process control graphics to process control algorithm information are described. An example method involves displaying a first process control image including process control algorithm information and displaying adjacent to the first process control image a second process control image to include process control graphics. The method automatically links at least some of the process control algorithm information to a graphic in the second process control image in response to user inputs associated with the first and second process control images.




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Graphical display for sorting and filtering a list in a space-constrained view

Techniques for sorting and filtering a list in a space-constrained viewing area are described. A filter widget and a list of items are displayed in a view of an electronic display screen. In response to user input selecting the filter widget, and without changing to a different view, a filter category overlay is displayed in the view to provide various selectable filter categories. In response to selection of a filter category, a visual depiction of the selected filter category is displayed in the view. The list of items is filtered according to the selected filter category and displayed in the view without changing to any other view. Subsequently added visual depictions are linearly stacked in the view. Further, a filter modification overlay, which provides selectable filtering attributes, is displayed upon selection of a visual depiction.




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Device, method, and graphical user interface for managing concurrently open software applications

A method includes displaying a first application view. A first input is detected, and an application view selection mode is entered for selecting one of concurrently open applications for display in a corresponding application view. An initial group of open application icons in a first predefined area and at least a portion of the first application view adjacent to the first predefined area are concurrently displayed. The initial group of open application icons corresponds to at least some of the concurrently open applications. A gesture is detected on a respective open application icon in the first predefined area, and a respective application view for a corresponding application is displayed without concurrently displaying an application view for any other application in the concurrently open applications. The open application icons in the first predefined area cease to be displayed, and the application view selection mode is exited.




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Methods and apparatus to determine impressions using distributed demographic information

An example method to monitor media exposure involves receiving, at a first internet domain, a first request from a client computer, the first request indicative of access to the media at the client computer. The example method also involves determining if the client computer is known. If the client computer is not known, a response is sent from the first internet domain to the client computer, the response to instruct the client computer to send a second request to a second internet domain, the second request to be indicative of access to the media at the client computer. If the client computer is known, an impression of the media is logged.




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Electronic device provided with cryptographic circuit and method of establishing the same

The present invention provides for an electronic device having cryptographic computation means arranged to generate cryptographic data within the device for enhancing security of communications therewith, the device including an onboard power supplying means arranged to provide for the driving of the said cryptographic computational means, and so as to provide a device by way of a manufacturing phase and a post manufacturing phase arranged for distribution and/or marketing of the device, and wherein the step of generating the cryptographic data occurs during the post manufacturing phase.




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Device and method for electroimpedance tomography

A device for electroimpedance tomography with an electrode belt (2), which has electrodes (E1 . . . E16), wherein at least two groups (5, 6) of electrodes located next to each other are formed and the electrodes of one group are contacted with at least one, multiwire feed cable (7, 8). For a reduced noise level during data acquisition, provisions are made for at least one electrode (E9) of two mutually adjacently located electrodes (E8, E9) of two different groups (5, 6) to have an additional electrode feed line (15), which is led over the feed cable (7) of the adjacent group (5).




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Method for bottom-up graphene sheet preparation and bandgap engineering

A combination of a substrate selected from silicon, silicon carbide or a metal and a grapheme precursor having the following properties: (a) an aromatic structure that forms the basis of the graphene structure, said aromatic structure being selected from the group consisting of: benzene, naphthalene, pyrene, anthracene, chrysene, coronene, and phenanthrene, or a cyclic or acyclic structures which can be converted to aromatic structures and (b) functional groups that can react with each other to form additional aromatic structures.