astronomy

Johan Bollen

Johan Bollen is a astronomy topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Johan Bollen rather than just read about it. In short: Johan Lambert Trudo Maria Bollen (born 1971) is a scientist investigating complex systems and networks, the relation between social media and a variety of socio-economic phenomena such as the financial markets, public health, and social well-being, as well as Science of Science with a focus on impact metrics derived from usage data. He presently works as Professor of Informatics and Cognitive Science at Indiana Univ…

Key takeaways

Johan Bollen belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Johan Bollen to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Johan Bollen from memory before moving on to harder problems.

Reference excerpt

Johan Lambert Trudo Maria Bollen (born 1971) is a scientist investigating complex systems and networks, the relation between social media and a variety of socio-economic phenomena such as the financial markets, public health, and social well-being, as well as Science of Science with a focus on impact metrics derived from usage data. He presently works as Professor of Informatics and Cognitive Science at Indiana University Bloomington and a fellow at the SparcS Institute of Wageningen University and Research Centre in the Netherlands. He is best known for his work on computational social science, scholarly impact metrics, measuring public well-being from large-scale social media data, and correlating Twitter mood to stock market prices. He has taught courses on collective intelligence, data mining, information retrieval, and digital libraries. His research has been funded by National Institute of Health, The Andrew W. Mellon Foundation, National Science Foundation, Library of Congress, National Aeronautics and Space Administration and the Los Alamos National Laboratory. In his free time, he DJs at the Root Cellar Lounge in Bloomington, Indiana. He specializes in Deep House and Techno.

Biography Bollen received his MS in experimental psychology from the Free University of Brussels in 1993 after a master thesis "Learning to Select Activities: a Conditionable System for an Autonomous Robot that Learns to Use Drive Reduction as Reinforcement." He defended his Ph.D. in psychology from the Free University of Brussels in October 2001 on the subject of cognitive models of human hypertext navigation. From 2002 to 2005 he was an assistant professor at the Department of Computer Science of Old Dominion University. He was a staff scientist at the Los Alamos National Laboratory from 2005 to 2009. He is currently a professor of Informatics and Cognitive Science at Indiana University.

Work Bollen's work has been extensively covered in the press and popular media and has received over 21,000 citations (2024 h-index 47). Bollen was awarded two patents: one for "Usage based indicators to assess the impact of scholarly works: architecture and method" (US 8135662 B2) and "Predicting economic trends via network communication mood tracking" (US 8380607 B2). His work has found widespread application, e.g. in systems for digital library recommendations systems (Ex Libris bX Recommender Service) and in systems that use social media information to generate financial trading signals. As a result of his work on predicting the stock market based on Twitter mood, Derwent Capital Markets started the Absolute Return fund, the worlds's first Twitter hedge fund. However, it later shut down after thirteen months.

Selected academic works Bollen has published over 100 papers. A selection of the highly cited ones:

2011, Twitter mood predicts the stock market. 2005, Co-authorship networks in the digital library research community. 2009, Modeling public mood and emotion: Twitter sentiment and socio-economic phenomena 2006: Bollen, Johan; Rodriquez, Marko A.; Van de Sompel, Herbert (2006). "Journal status". Scientometrics. 69 (3): 669–687. 2009, A Principal Component Analysis of 39 Scientific Impact Measures 2005, Toward alternative metrics of journal impact: A comparison of download and citation data 2014, Proposed SOFA, a new method for distribution of research funding.

References

Worked examples

Example 1 — a first encounter with Johan Bollen

Start with the simplest possible case. Write down what Johan Bollen claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In astronomy, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Johan Bollen before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Johan Bollen ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Johan Bollen

In research: Johan Bollen appears in astronomy research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Johan Bollen in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Johan Bollen is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1971 births, Belgian academics, Belgian computer scientists, so understanding it makes those chapters shorter.
In everyday life: Look for Johan Bollen outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Johan Bollen in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Johan Bollen means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Johan Bollen out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Johan Bollen in simple terms?

Why does Johan Bollen matter?

Because it connects several astronomy ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Johan Bollen?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Johan Bollen.