Topics

In machine learning and natural language processing, a topic model is a type of statistical model for discovering the abstract "topics" that occur in a collection of documents. Intuitively, given that a document is about a particular topic, one would expect particular words to appear in the document more or less frequently: "dog" and "bone" will appear more often in documents about dogs, "cat" and "meow" will appear in documents about cats, and "the" and "is" will appear equally in both. A document typically concerns multiple topics in different proportions; thus, in a document that is 10% about cats and 90% about dogs, there would probably be about 9 times more dog words than cat words. A topic model captures this intuition in a mathematical framework, which allows examining a set of documents and discovering, based on the statistics of the words in each, what the topics might be and what each document's balance of topics is (source: Wikipedia).


List of Topics extracted from this document collection

1. particles size volume particle microns dispersion weight parts casting viscosity surface cm density average thick min distribution inch maximum sheet
2. mold surface lens method material fig member optical cavity surfaces glass form molded area fibers polymer blank silicon body lenses
3. fig end material means member assembly cast portion surface outer upper wall invention body apparatus view shown lower support side
4. reaction invention product anhydride process solvent copolymer carbon formula copolymers reactant polymerization atoms polymers free maleic radical vinyl units dioxolane
5. component percent liquid mixture binder weight polymer cement composition water temperature material compositions silica free strength comprises process reactive solid
6. weight acid methacrylate composition monomer acrylate methyl vinyl compositions preferably monomers organic resin groups glycol polymer copolymer examples parts alkyl
7. polymer acid solution poly conductive electrode film substrate invention claim oxide present form method thin conductivity solvent gas metal electrically
8. layer metal ceramic alloy core tape pattern elements material green method invention casting transducer alloys slip process step article form
9. filler composite particles material matrix film casting composition liquid invention method substrate present suitable particulate viscosity layer filled fluoropolymer al
10. film casting solution solvent polymer layer process surface percent invention thickness films weight preferably substrate support composite liquid formed claim
11. coating coated paper polymer surface fiber material adhesive cast pipe layer method applied aluminum side gloss invention plastic roll pigment
12. casting metal powder composition polymer invention zinc coating parts mold boron water oxide weight nitride agent steel surface peroxide resin
13. polymer graft blend weight melt copolymer polymers polypropylene ethylene film polyethylene blends table molecular extrusion high low copolymers poly density
14. polymer str liquid polymers ml group hours weight groups reaction formula ch temperature cf process prepared film fluorine compound form
15. polymer weight drug release screw nut molecular lead method casting amount adhesive composition controlled claim system clay high threads cavity
16. polymer acrylic cast composition monomer polymerization preferably temperature fabric resin acrylate material heat time minutes method initiator present reaction amount
17. membrane membranes polymer solvent separation process temperature gas preferably mixture solution porous water pore poly weight flux invention casting cast
18. invention present polymer fig high cast low surface rubber art liquid shown materials provide accordance effect light improved diameter conventional
19. water solution film polyvinyl soluble cellulose alcohol added aqueous acetate polymer weight acid emulsion starch films reaction mixture cast vinyl
20. membrane polymer solution water surface resin hydrophilic groups casting invention filtration claim matrix acid structure ml method modifying modified system
21. sheet temperature roll heat side casting mm melt obtained cooling cathode cell surface rate process crystallization degree high treatment thickness
22. acid aromatic grams invention amine solution mole bis mixture chloride molecular compounds added prepared formula polyimide str ester temperature reaction
23. polymerization plate monomer methacrylate weight resin methyl surface zone syrup mm parts synthetic process water obtained belts group polymer table
24. parts polyurethane diisocyanate reaction isocyanate urethane prepolymer groups glass mixture added molecular diol invention radiation temperature hydroxyl glycol polyol polyether
25. product process cross resin weight invention catalyst material claim products polymer pat set linking plastic number making linked present polyester

Having understood the concept of topics it is clear that it is possible to calculate them as a function of time. Here are some results ...