The Programming Historian 2 Editor’s Note This lesson requires you to use the command line. If you have no previous experience using the command line you may find it helpful to work through the Programming Historian Bash Command Line lesson. Lesson Goals In this lesson you will first learn what topic modeling is and why you might want to employ it in your research. Please see the MALLET users’ discussion list for the full range of things one can do with the software. (We would like to thank Robert Nelson and Elijah Meeks for hints and tips in getting MALLET to run for us the first time, and for their examples of what can be done with this tool.) What is Topic Modeling And For Whom is this Useful? A topic modeling tool takes a single text (or corpus) and looks for patterns in the use of words; it is an attempt to inject semantic meaning into vocabulary. Topic models represent a family of computer programs that extract topics from texts. Examples of topic models employed by historians: Installing MALLET Mac Instructions .
Chemical reaction A thermite reaction using iron(III) oxide. The sparks flying outwards are globules of molten iron trailing smoke in their wake. A chemical reaction is a process that leads to the transformation of one set of chemical substances to another.[1] Classically, chemical reactions encompass changes that only involve the positions of electrons in the forming and breaking of chemical bonds between atoms, with no change to the nuclei (no change to the elements present), and can often be described by a chemical equation. Nuclear chemistry is a sub-discipline of chemistry that involves the chemical reactions of unstable and radioactive elements where both electronic and nuclear changes may both occur. Chemical reactions happen at a characteristic reaction rate at a given temperature and chemical concentration, and rapid reactions are often described as spontaneous, requiring no input of extra energy other than thermal energy. History Equations Dissociation of a molecule AB into fragments A and B
Downloading MALLET Current release: The following packaged release of MALLET 2.0 is available: Windows installation: After unzipping MALLET, set the environment variable %MALLET_HOME% to point to the MALLET directory. In all command line examples, substitute bin\mallet for bin/mallet. Development release: To download the most current version of MALLET 2.0, use our public Mercurial repository. After installing the Mercurial distributed version control system, use the command hg clone from the command prompt to get the Mallet package. To build a Mallet 2.0 development release, you must have the Apache ant build tool installed. ant If ant finishes with "BUILD SUCCESSFUL", Mallet is now ready to use. If you would like to deploy Mallet as part of a larger application, it is helpful to create a single ".jar" file that contains all of the compiled code. ant jar This process will create a file "mallet.jar" in the "dist" directory within Mallet.
MultiTrees (Part 1) Posted in: javascript infovis toolkit , visualization I found this CHI 94' visualization paper on MultiTrees in the internet and I've been trying to see what type of applications and ideas I could "borrow" for the JavaScript InfoVis Toolkit. What are MultiTrees? A MultiTree is a type of directed acyclic graph (DAG) where each node has a tree both as parent structure and as descendants. For example, a MultiTree can be created by overlapping different tree structures on a set of nodes, as shown in the picture below: As you can see MultiTrees can have cycles if they're not directed. Laying and Navigating MultiTrees What's interesting about this structure is that if we take two nodes x and y such that x <= y and the path connecting them, then we can form a topological tree by adding all descendants and ancestors of each node belonging to that path in the new graph. Implementation I recently pushed support for a small subset of MultiTrees: those where x = y. 4 Comments
Demos - JavaScript InfoVis Toolkit JavaScript InfoVis Toolkit Create Interactive Data Visualizations for the Web Home ● Download ● Builder ● Donate Area, Bar and Pie Charts Sunburst Icicle ForceDirected TreeMap SpaceTree RGraph HyperTree Advanced/Other copyright © 2013 SenchaLabs - Author: Nicolas Garcia Belmonte John Lafferty @UChicago My primary research is in machine learning and statistics, with basic research on theory, methods, and algorithms. I am especially interested in nonparametric methods, sparsity, and graphical modeling for high-dimensional data. A few examples of past research projects are given below. Graph and density estimation This project looks at nonparametric graphical models in high dimensions. Forest density estimation Han Lu, Min Xu, Haijie Gu, Anupam Gupta, John Lafferty and Larry WassermanJ. Topic modeling Topic models assume the words of a document arise from a mixture of topics, each of which is a distribution over the vocabulary. Topic models David Blei and John Lafferty In A. Semisupervised learning In many applications annotations are expensive to obtain, but unlabeled data are relatively cheap.
Elementary reaction An elementary reaction is a chemical reaction in which one or more of the chemical species react directly to form products in a single reaction step and with a single transition state.[1] At constant temperature, the rate of such a reaction is proportional to the concentration of the species A The rate of such a reaction, at constant temperature, is proportional to the product of the concentrations of the species A and B The rate expression for an elementary bimolecular reaction is sometimes referred to as the Law of Mass Action as it was first proposed by Guldberg and Waage in 1864. Jump up ^ IUPAC, Compendium of Chemical Terminology, 2nd ed. Reaction rate Iron rusting has a low reaction rate. This process is slow. Wood combustion has a high reaction rate. Chemical kinetics is the part of physical chemistry that studies reaction rates. [edit] Consider a typical chemical reaction: aA + bB → pP + qQ According to IUPAC's Gold Book definition[1] the reaction rate r for a chemical reaction occurring in a closed system under isochoric conditions, without a build-up of reaction intermediates, is defined as: where [X] denotes the concentration of the substance X. For any open system, the full mass balance must be taken into account: IN - OUT + GENERATION - CONSUMPTION = ACCUMULATION where is the inflow rate of A in molecules per second, the outflow, and is the instantaneous reaction rate of A (in number concentration rather than molar) in a given differential volume, integrated over the entire system volume at a given moment. , where the concentration is related to the number of molecules by . is the Avogadro constant. Here is the volume of reaction and [edit]
Elias James Corey Elias James "E.J." Corey (born July 12, 1928) is an American organic chemist. In 1990, he won the Nobel Prize in Chemistry "for his development of the theory and methodology of organic synthesis", specifically retrosynthetic analysis.[1][2] Regarded by many as one of the greatest living chemists, he has developed numerous synthetic reagents, methodologies, total syntheses, and has advanced the science of organic synthesis considerably. Biography[edit] E.J. Corey (the surname comes from khoury family in lebanon, meaning the priest in arabic) was born to Christian Lebanese immigrants in Methuen, Massachusetts, 50 km (31 mi) north of Boston. Corey entered MIT at the age of 16 where he earned both a bachelor's degree in 1948 and a Ph.D. under Professor John C. In 1988, he was awarded the National Medal of Science.[6] He was awarded the American Chemical Society's greatest honor, the Priestley Medal, in 2004. Major contributions[edit] Reagents[edit] E.J. 1,3-Dithianes were pioneered by E.J.