...and shortened version of Gr¨n and Hornik (2011), u published in the Journal of Statistical Software. Topic models allow the probabilistic modeling of term frequency occurrences in documents. The fitted model can be used to estimate the similarity between documents as well as between a set of specified keywords using an additional layer of latent variables which are referred to as topics. The R package topicmodels provides basic infrastructure for fitting topic models based on data structures from the text mining package tm. The package includes interfaces to two algorithms for fitting topic models: the variational expectation-maximization algorithm provided by David M. Blei and co-authors and an algorithm using Gibbs sampling by Xuan-Hieu Phan and co-authors. Keywords: Gibbs sampling, R, text analysis, topic model, variational EM. 1. Introduction In machine learning and natural language processing topic models are generative models which provide a probabilistic framework for the term frequency occurrences in documents in a given corpus. Using only the term frequencies assumes that the information in which order the words occur in a document is negligible. This assumption is also referred to as the exchangeability assumption for the words in a document and this assumption leads to bag-of-words models. Topic models extend and build on classical methods in natural language processing such as the unigram model and the mixture of unigram models (Nigam, McCallum, Thrun, and Mitchell...
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...Adulthood The topic in social development I chose to write about is mid-life transition or how it is more commonly known mid-life crisis. The reason I decided to go with mid-life transition is that I find it fascinating that we go through so many different changes during adolescence, then we have a large amount of time before our minds need to “reset” again. I see the timing of a mid-life crisis as a time to take control over your life again, break away from the routine that we create for ourselves and use the opportunity to try something new, or broaden our horizons. The article I read that peaked my interest about the dreaded mid-life crisis is “Mid-life Crisis? Bring it on!” it was published by Time magazine in May of 2005 by Nancy Gibbs. It takes a different approach to the mid-life crisis and provides new insight and ways to make your own a positive one. The article started with a story about how the author is going through her own mid-life transition and learning how to own it, instead of letting it own her. The article continues on to tell how the changes that we go through in life shape us into to who we are and how the mid-life transition plays a role in continuing that process. If I was writing a report of how to come out of a mid-life crisis feeling on top, instead of following the mainstream path of “just a phase” this is a definite choice I would pick for a resource. I would not use it if I wanted to get more into the psychology and the understanding of what...
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...Case Study #5 “He said….She Said” Vicky McFerren Lankford Che Baysinger CM301-02 In the case of “He Said, She Said”, Marie is always trying to protect her son, no matter what the cost to her relationship with her fiancé Mike. Lenny on the other hand, seems to be the lower-powered person using seduction to try and charm or trick his mother into going along with what he wants. Marie uses avoidance and destructive competition instead of resolving the matter in a more collaborative or accommodating way. While Mike wants to engage in conflict to resolve the matter, Marie wants to protect her son by avoiding it, no matter what the cost to their relationship. Marie’s preference for engaging or avoiding Mike can develop into a rigid style, and when this happens, constructive conflict becomes very difficult according to Wilmot and Hocker. Every time the issue of her son defying the rules and doing as he pleases comes up, Marie and Mike will have to reach some type of an agreement on the “avoidance/engagement”, or this metaconflict will override any other emerging issues (Wilmot & Hocker)”. Marie uses avoidance to sidestep the issue by withdrawing from the issue and destructive competition through personal criticism when she tells Mike; “Real punishment? How would you know? You never had children. What do you know about being a parent? You never even call your own mother.” (Case Study) This competitive tactic can often damage a relationship. It “locks the...
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...All the citizens of New York were startled by the low altitude flyovers. The unannounced fly-over brought back memories of 9/11. The 911 and 311 phone lines were flooded. That took away from real emergencies but the communities didn’t know what was going on. 2. Critique the implementation process. If there were problems, how would you characterize them? A coordination issue? A communication issue? Something else? The plans were made right but the communication process was totally wrong. The lack of communication threw the whole process off. Everybody in New York should had known about the fly-over days prior to the event actually happening. The personnel that worked at the White House didn’t even know including Jim Messina or Robert Gibbs. Even if the citizens had found out late, Caldera could had ran it across the New York television channels all morning or aired it on the radio stations. 3. What is your take-away from this analysis? In other words, what would you say is the “moral of the story”? The moral of the story is communication is a key part to success regardless if it is in planning an event, running a business or even in personal relationships. If communication is lacking then the whole project or mission will fall apart in the end. 4. Think “big picture”. In the broadest sense, who is the “hosting” organization (company, school, government agency) having the situation/dilemma? What would you say is that organization’s mission? Does the approach that the players...
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... The first marathon was run at the Olympic Games in Athens in 1896. (“Marathon History”) For seventy years, running a marathon was strictly a men-only activity. That was until the 1967 Boston Marathon, when the name K.V. Switzer showed up on a marathon registration. (“Kathrine Switzer Biography”) Little did the race officials know, K.V. Switzer was actually Katherine Virginia Switzer. In the pictures shown of the race that day, it is evident that Switzer was attacked by race officials for her heroic act for women in sports. Even though a grey sweat suit is not particularly the most noble and valiant look, seeing Switzer open a new window for women’s running is courageous enough to be considered a hero for any runner to this day. Although these photos are not posed, clear acts of heroism can be depicted. In the chosen pictures, Switzer is running in the 1967 Boston Marathon. Race official Jock Semple, pictured in black, is seen chasing after Switzer. Switzer claimed Semple yelled, “Get the hell out of my race and give me those numbers.” Switzer’s boyfriend, Tom Miler, then shoved Semple aside, letting Switzer continue on. When asked why she didn’t drop out, Switzer states, “I knew if I did that no one would believe women could run distances and deserved to be in the Boston Marathon; they would just think that I was a clown, and that women were barging into events where they had no ability.” Switzer is the only female shown in the picture, as running a marathon was considered...
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...ntropyTake-Home Challenge Entropy, Enthalpy, and Free Energy The equation relating these factors is: ∆G = ∆H–T∆S, where G is free energy, H is enthalpy, S is entropy, and T is temperature (in Kelvin). Although temperature values will always be positive, entropy, enthalpy, and free energy values can be positive or negative. For a given process, a quantitative value for each factor can be calculated using the known values of the factors for each reactant involved (see Table 1) according to the general equation ∆ X°rx = Σ X°(products)–Σ X°(reactants). See if the following activity helps you better understand what these quantities really mean. Table 1 HCO3 H+ H2O (l) CO2 (g) - ∆Η° (kJ/mol) -691.1 0 -285.8 -393.5 S° (J/K mol) 94.94 0 69.9 213.6 ∆G° (kJ/mol) -587.1 0 -237.2 -394.4 Materials • • • • • vinegar baking soda thin-walled cup tablespoon measure teaspoon measure Exploration Step 1 Put about 2 tablespoons vinegar in a cup. Add a teaspoon or two of baking soda to the cup. (a) What do you observe through sight, sound, and touch? (b) What kind of change is occurring? (c) What are the formulas of the 2 major components of vinegar and of the one component of baking soda? (d) Write the overall equation and the net ionic equation for the process. Step 2 (a) Define entropy and the significance of the sign of its value. (b) Based on your observations, explain the entropy change for the system observed in Step 1. (c) Use the entropy data from Table 1 to calculate...
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...CHM1202 Assignment 2014-15 NAME: _________________________ Reg No. ________________________ Instructions: Answer all questions in the spaces provided. The completed assignment should be submitted to one of the Course Lecturers or the Departmental Secretary no later than 15:00 h on Friday May 8, 2015. a. Ammonia is manufactured using the equation; N2 (g) + 3H2 (g) ↔ 2NH3 (g) i) Use the data provided to calculate the entropy change for this reaction at 700K [4] At 700 K; S (N2) = 212 J/K.mol; S (H2) = 149 J/K.mol; S (NH3) = 245 J/K.mol ii) Using ideas about disorder, explain whether the sign of your answer to part a (i) is as expected. [2] ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ iii) At 700 K the enthalpy change for the formation of NH3 is -55.1 kJ/mol. What is the Gibb’s energy change of the reaction in a (i) at 700K? (Include a sign and units in your answer). [5] b. Use your answer to part a (iii) to calculate the equilibrium constant Kc for the reaction at 700 K; hence or otherwise state whether reactants or products are favoured at equilibrium. [5] c. A mixture of N2, H2 and NH3is at equilibrium. The total pressure of the system is 150 atm. The partial pressures of N2 and NH3 in the mixture are 21 atm and 36 atm respectively. i)...
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...Introduction and Concepts January 23rd 2013 Thermodynamics: Is the science that deals with work, heat and other form of energy (Kinetic Energy, Potential Energy, Enteral Energy) also their transformation and their relationships with properties. Definitions • System (closed system): A region isolated from the rest of the matter that under study. Nothing crosses boundaries. • Surrounding: Everything external and not in the system. • Control System (open system): A region where mass may cross the boundary of a control volume. Examples: Turbines – Niggles – Compressors – Heat Exchange – Pumps – Pipe Flows. • Properties: Are the Microscopic Characteristics of a System / of a Control Volume. Examples: Temperature - Pressure – Density – Volume – Internal Energy – Enthalpy and Entropy. • Extensive Properties: A Property if its value for an overall system is the sum of its values for the parts into which system is divided. Examples: Mass - Volume. • Intensive Properties: Properties are not additive and in the sense of previously considered. Example: Pressure. • Processes: A change of state of a system or control volume. • Cycle: A process whose initial and final states are identical. • Thermodynamic equilibrium: For thermodynamic equilibrium the following must be satisfied → o Mechanical equilibrium: A condition of balanced Forces. o Thermal equilibrium: No Change in Temperature. o Chemical equilibrium: No chemical reaction. o Electrical equilibrium:...
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...Introduction to the Thermodynamics of Materials Third Edition David R. Gaskell Preliminaries ‡ Settings Off@General::spellD ‡ Physical Constants Needed for Problems ü Heat Capacities The generic heat capcity c 105 bT Å Cp = a + ÅÅÅÅÅÅÅÅÅÅ + ÅÅÅÅÅÅÅÅÅÅÅÅÅÅ ; T2 103 The heat capacities of various elements and compounds are CpAgs = Cp ê. 8a Ø 21.30, b Ø 8.54, c Ø 1.51 8.3144 , Rla -> 0.082057 < ; The number of moles can be calculated from the starting state: P 1 V1 nmols = ÅÅÅÅÅÅÅÅÅÅÅÅÅÅÅÅ ê. nums ; Å Rla T1 subs = Append@nums, n -> nmolsD 8V1 Ø 10, T1 Ø 298, P1 Ø 10, P2 Ø 1, R Ø 8.3144, Rla Ø 0.082057, n Ø 4.08948< Finally, this constant will convert liter-atm energy units to Joule energy units. All results are given in Joules: laToJ = 101.325 ; ü 1. Reversible, Isothermal Process In an isothermal process for an ideal gas, DU = 0 ; DH = 0 ; thus heat and work are equal and given by: P2 q = w = n R T1 LogA ÅÅÅÅÅÅÅ E J ê. subs P1 -23330.9 J 16 Notes on Gaskell Text ü 2. Reversible Adiabatic Expansion In an adiabatic expansion q = 0; and P V g is a constant. Thus the final state has 1êg g P2 V2 i P1 V1 y Å ; T2 = ÅÅÅÅÅÅÅÅÅÅÅÅÅ ê. g -> 5 ê 3 Å V2 = j ÅÅÅÅÅÅÅÅÅÅÅÅÅÅÅ z j z n Rla k P2 { P1 V 1 P2 I ÅÅÅÅÅÅÅÅÅÅÅÅÅ M P ÅÅÅÅÅÅÅÅÅÅÅÅÅÅÅÅ2 ÅÅÅÅÅÅÅÅÅ ÅÅÅÅÅÅÅÅ Å n Rla 5ê3 3ê5 For an ideal gas cv = 3R/2; thus 3 DU = ÅÅÅÅ n R HT2 - T1 L ê. subs 2 -9147.99 or we can use 3 DU = ÅÅÅÅ HP2 V2 - P1 V1 L laToJ ê. Append@subs, g -> 5 ê 3D 2 -9148.02 For some numeric results, the...
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...A spontaneous process is the time-evolution of a system in which it releases free energy (usually as heat) and moves to a lower, more thermodynamically stable energy state. The sign convention of changes in free energy follows the general convention for thermodynamic measurements, in which a release of free energy from the system corresponds to a negative change in free energy, but a positive change for the surroundings. A spontaneous process is capable of proceeding in a given direction, as written or described, without needing to be driven by an outside source of energy. The term is used to refer to macro processes in which entropy increases; such as a smell diffusing in a room, ice melting in lukewarm water, salt dissolving in water, and iron rusting. The laws of thermodynamics govern the direction of a spontaneous process, ensuring that if a sufficiently large number of individual interactions (like atoms colliding) are involved then the direction will always be in the direction of increased entropy (since entropy increase is a statistical phenomenon). Entropy is a chemical concept that is very difficult to explain, because a one-sentence definition will not lead to a comprehensive statement. Thus, few people understand what entropy really is. You are not alone if you have some difficulty with this concept. The word entropy is used in many other places and for many other aspects. We confine our discussion to thermodynamics (science dealing with heat and changes)...
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...Laws of Thermodynamics Joshua Gibbs Grantham University First Law of Thermodynamics: The first law states that Energy can neither be created nor destroyed. Energy just changes its form from one to another. The total energy present in the universe remains constant. Examples of the first law of thermodynamics can be: Electrical Bulbs convert electrical energy to light energy; Mechanical systems in cars convert the heat energy released from petrol into kinetic energy. Second Law of Thermodynamics This law states that energy of all forms moves from higher concentration of energy to lesser concentration energy. When energy moves from high concentration to lesser concentration then some energy is dispersed or spreads out. Entropy is a measure of how much energy is spread out in a particular process. Examples are: When we exercise not all of our energy is converted into muscles in fact more energy disperses away in sweat. The Second Law of Thermodynamics implies that high-quality energy can never be used over again. Once a barrel of Oil is burned its high energy is lost forever. We cannot use the same barrel of oil to burn again. The diesel engine of a generator converts fuel energy into mechanical and thermal energy. During this process of conversion of energy some of the energy is lost or leaked out as heat from the wires of generator or dissipated as heat from the machine. The total amount of energy has not changed but it is now so dispersed that it can never be re-used...
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