Literature Search http://www.pds.ewi.tudelft.nl/~iosup/Courses/2011_aiosup_lit_search.ppt IN 3305 Alexandru Iosup and Tomas Klos. Parallel and Distributed Systems Groep http://www.pds.ewi.tudelft.nl/
Innovation: Vital Competitive Tool Source: Economist Intelligence Unit, A new ranking of the world’s most innovative countries, April 2009, http://graphics.eiu.com/PDF/Cisco_Innovation_Complete.pdf • Innovation = novel application of knowledge • Innovation favors small (but efficient) countries • High-tech companies tend to be more innovation-intensive
Number of Publications 19931997 19972001 Data: King,The scientific impact of nations,Nature’04. What is Novel?The Overwhelming Growth of Knowledge “When 12 men founded the Royal Society in 1660, it was possible for an educated person to encompass all of scientific knowledge. […] In the last 50 years, such has been the pace of scientific advance that even the best scientists cannot keep up with discoveries at frontiers outside their own field.” Tony Blair, PM Speech, May 2002
The “Size” of a Research Topic • Grid Computing • Billions of $ in research investment • 2,500 PhDs (my est.) • Over 15,000 scientific publications (my est.) in 15 years • Several surveys of 100-200 articles each • Grid Scheduling • Conferences: Grid, CCGrid, HPDC, SC, IPDPS, ICDCS, … • Journals: TPDS, CCPE, FGCS, JoGC, … • Peer-to-Peer Search Methods • Survey of over 300 articles after 5 years of research
How to Talk About Books You Haven’t Read • “There is more than one way not to read” • Not opening the book • You cannot read everything • How many books can you read? • How many books can a librarian read? • Librarians can talk about every book in the library (every book out of millions) There exists a system to (not) read
Literature Surveys: At the Core of Innovation Given a problem (topic of interest) Answer questions about it • What solutions exist? • What is the most influential solution? • What is the rate of innovation in the field? By surveying (understanding, interpreting, and summarizing) the body of related (scientific) knowledge. • Where and how can I innovate? IN3305’s study goal “kennismaken met wetenschappelijke literatuur”
Outline • From the IN3305 study goals: “kennismaken met wetenschappelijke literatuur” • To read or not to read? • What is “scientific literature”? • Literature is inputandoutput • Measuring and assessing Quality • Useful sites and tools • On gaming the citation indices (unethical) • Conclusion
Literature = input Citations Place your work in context Give credit to previous work Support your arguments Show your marginal contribution Prevent plagiarism Read what you cite! (prevent superfluous citing)This does NOT mean: “You should read everything” “You cannot also read what you don’t cite” March 11, 2014 8
Quality? Reputation: ACM, IEEE, Springer, Elsevier, MIT/Princeton/Oxford/… University Press SCIgen - An Automatic CS Paper Generatorhttp://pdos.csail.mit.edu/scigen/accepted (non-reviewed) for: 2005 World Multi-Conference on Systemics, Cybernetics and Informatics (another one: an Elsevier journal!) March 11, 2014 9
Sources: peer-reviewed Textbook/monograph: for teaching and background Complete treatment of a topic Cite a textbook? Mention chapter or page number Journal article More space, detail, thorough than conference paper Sometimes old news at publication date (lag) Paper in edited volume: Multiple papers, review of state-of-the-art Cite individual papers Paper in conference proceedings Recent results Conference quality; publisher of proceedings? March 11, 2014 10
Sources: not peer-reviewed Working papers, Preprints Up-to-date, spread ideas “Open access” Computing Research Repository (CoRR)http://arxiv.org/corr/home Websites ‘Personal communication’ March 11, 2014 11
Literature = output • Publish to conferences and journals • Peer-review (for conferences, journals): • (double) blind review: Accept, with/without (major) revisions Reject • Acceptance rate ratio, e.g., 25% (not bad) • (Nature: 10% articles are reviewed) • Measuring scientific output: “scientometrics”
Scientometrics • Scientometrics, “measuring and analyzing science”, • Bibliometrics, “study or measurement of texts and information” • Citation analysis • Which papers cite a paper / does a paper cite? • Authorityof countries, research groups, individual authors, journals/conferences, individual paper Q What is a citation? • “Publish or perish”: quality vs quantity • (“80% of all published papers are not cited”) Q Conference or journal? Which conference or journal?
Comparing Countries Citation intensity= #Citations/GDP Citation rate per paper, norm. Data: King, The scientific impact of nations, Nature’04.
Time Comparing Groups or Individuals [1/3] • An idea: Google PageRank principle • Web: network of sites, linking to each other • Science: network of papers, citing each other World Wide Web’s Links Network Academic Citations Network Q Problems with this approach?
Comparing Groups or Individuals [2/3] • Journals: Journal Impact Factor • Personal: h-index (Hirsch, 2005): A scientist has index h if h of his/her N papers have at least h citations each, and the other (N − h) papers have no more than h citations each. Used in practice. • Extensions: g-index, e-index; group evaluation QWhat about conferences? QReally, what is a citation? Q (unethical) How to abuse citation indices?
Citation Databases • Commercial • ScienceCitation Index (Web of Science/Inf. Sci. Inst.) • Scopus (Elsevier) • Free • Google Scholar: better coverage than ISI • CiteSeer (computer science) • ArNetMiner (computer science) • RePec (economics) • More: en.wikipedia.org/wiki/List_of_academic_databases_and_search_engines
Journal Impact Factor (JIF) • Many journals have no impact factor • JIF is the average number of citations in a given year, to papers in a journal in the 2 previous years. • For journal x, 2008 number of citations in 2008 to papers in journal xfrom the period 2006 – 2007 JIF (x, 2008) = Total number of papers in journal xin the period 2006 – 2007 • What does an average value mean?
Journal Impact factors, 2004 JIF ≥1 citation/publication(last 2 years) Journal Rank Highest JIF ~30 Very high JIF ≥15
CS impact factors, 2005 JIF Journal Rank CS All Highest JIF ~8 Very high JIF ≥2 Highest JIF ~30 Very high JIF ≥15
Comparing Groups or Individuals [3/3]For Computer Science • Conference proceedings are to be preferred to journals • ISI Web of Science and Elsevier Scopus are not good impact indicators—poor, albeit improving, coverage • Google Scholar is a better impact indicator than ISI WoS and Elsevier Scopus; ArNetMiner is reasonable • DBLP is a good, selective source, but has no citation links • Expert knowledge is required to select the best topical conferences and journals (regardless of their acceptance ratios and impact factors) Q Problems with this approach?
Outline From the IN3305 study goals: “kennismaken met wetenschappelijke literatuur” To read or not to read? What is “scientific literature”? Literature is input and output Measuring and assessing Quality Useful sites and tools On gaming the citation indices (unethical) Conclusion March 11, 2014 22
Method To Find Sources Browse: Google Scholar: http://scholar.google.com/ DBLP: http://dblp.uni-trier.de/ Others: TU Delft library tools Study author using Publish or Perish Look at author homepages Follow links and citations (forward and backward) March 11, 2014 23
Google Scholar • “cited by” • Relevant authors • TU Delft SFX linking • Import into bibtex
Google Scholar at Work From home: use vpn!
DBLP • “lists more than one million articles” (april 2008) • Indexes: • Authors • Now also “Faceted search”, “CompleteSearch” • Conferences • Journals • Series • Subjects
TU Delft Library Search http://www.library.tudelft.nl/ws/search/ e.g. “information by subject” -> computer science TUlib “how to find and use scientific information” http://www.library.tudelft.nl/tulib/ March 11, 2014 34
Harzing’s Publish or Perish • Uses Google Scholar data • Calculates many indices • Number of citations (also per year / article / author /…) • Hirsch’s h-index • Zhang’s e-index (excess in h-index set) • Egghe’s g-index • … • Similar online tool: ArNetMiner
Outline From the IN3305 study goals: “kennismaken met wetenschappelijke literatuur” To read or not to read? What is “scientific literature”? Literature is input and output Measuring and assessing Quality Useful sites and tools On gaming the citation indices (unethical) Conclusion March 11, 2014 37
Unethical!How to Game the Citation System?(part of)Collaboration graph
All authors with Erdős number 1 Note: The h-index was “invented” almost a decade after Erdos.
Collaboration Graph: Connected Components Distribution Giant Component
Interested? • Mark Newman analyzes the phenomenon: “who is the best connected scientist?” • Other references • Erdős Number Project http://www.oakland.edu/enp/ • Kevin Bacon Oracle http://oracleofbacon.org/
More on the (unethical) Gaming the Citation Indices • Self-cite, self-cite, self-cite • Journals asking for submitters to cite journal’s papers • Program committee members and reviewers asking for their own work to be cited (when not necessary) • Not citing old work because it’s old—”killing” old results now allows you to republish them later • Work on a popular topic—more people, more citations, more chances • (Google Scholar-only) Blog, Tweet, and FB daily about your papers. Ask your friends to re-post.
How to Talk About Books You Haven’t Read There exists a system to (not) read • Know where to find sources • Trustworthy: DBLP, ACM DL, Google Scholar • Less trustworthy: CoRR, … • Know how to find good sources • Number of citations: Google Scholar+Others • H-index: Publish or Perish (the program) • Try to avoid or weight-out citation cliques • Select from the good sources