computer science

John Hershberger

John Hershberger is a computer science 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 John Hershberger rather than just read about it. In short: John E. Hershberger (born 1959) is an American computer scientist and software professional, a principal engineer at Mentor Graphics Corporation since 1993.

Key takeaways

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

Reference excerpt

John E. Hershberger (born 1959) is an American computer scientist and software professional, a principal engineer at Mentor Graphics Corporation since 1993. He is known for his research in computational geometry and algorithm engineering.

Biography Hershberger did his undergraduate studies at the California Institute of Technology, graduating in 1981. He earned a Ph.D. in Computer science from Stanford University in 1987 under the supervision of Leonidas Guibas. He was a member of the technical staff at the Digital Equipment Corporation Systems Research Center in Palo Alto, California, until 1993, when he joined Mentor Graphics as a software engineer and project leader. He was program committee chair for the 25th ACM Symposium on Computational Geometry in 2009, and program committee co-chair for the Workshop on Algorithm Engineering and Experiments (ALENEX) in 2009. In 2012 he was elected as a fellow of the Association for Computing Machinery "for contributions to geometric computing and to design tools for integrated circuits". He lives in Tigard, Oregon.

Contributions

Computational geometry John Hershberger has been a significant contributor to computational geometry and the algorithms community since the mid-1980s. His earliest work focused on shortest paths and visibility. With Leonidas Guibas and by himself, he devised optimal linear-time algorithms to compute visibility polygons, shortest path trees, visibility graphs, and data structures for logarithmic-time shortest path queries in simple polygons. With Jack Snoeyink he extended the algorithms for simple polygons to compute homotopic shortest paths among polygonal obstacles in the plane. He also invented parallel algorithms to solve several shortest path and visibility problems. One of the most significant achievement of this period is his algorithm (joint work with Subhash Suri) to compute shortest paths among polygonal obstacles in the plane using only O(n log n) time. This algorithm was a vast improvement over the roughly quadratic running time achievable by visibility-graph-based methods, and resolved a problem that had been open and intensely studied for years. Data structure for "Pedestrian ray shooting", devised by John and Subhash Suri, answers ray shooting queries in a simple polygon. It consists of a special triangulation such that any line segment inside the polygon intersects only O(log n) triangles; ray shoot-ing queries can be answered simply by walking from triangle to triangle until the query ray hits the polygon boundary. Kinetic data structures, proposed by Leonidas Guibas, Julien Basch and Hershberger, have been and continue to be influential in computational geometry. Working by himself and with a variety of co-authors, John devised kinetic data structures to maintain the extent of moving points; the connected components of moving unit disks, rectangles, and hypercubes; clusters for sets of moving points; and data structures to detect collisions between polygons in motion.

Selected publications Guibas, Leonidas; Hershberger, John (1989), "Optimal shortest path queries in a simple polygon", Journal of Computer and System Sciences, 39 (2): 126–152, doi:10.1016/0022-0000(89)90041-x. Hershberger, John; Suri, Subhash (1999), "An optimal algorithm for Euclidean shortest paths in the plane", SIAM Journal on Computing, 28 (6): 2215–2256, CiteSeerX 10.1.1.47.2037, doi:10.1137/S0097539795289604, MR 1698954 {{citation}}: Cite uses deprecated parameter |citeseerx= (help). Basch, Julien; Guibas, Leonidas; Hershberger, John (1999), "Data structures for mobile data", Journal of Algorithms, 31 (1): 1–28, CiteSeerX 10.1.1.134.6921, doi:10.1006/jagm.1998.0988, S2CID 8013433 {{citation}}: Cite uses deprecated parameter |citeseerx= (help). Hershberger, John; Maxel, Matt; Suri, Subhash (2007), "Finding the k shortest simple paths: A new algorithm and its implementation", ACM Transactions on Algorithms, 3 (4), Article 45, doi:10.1145/1290672.1290682, S2CID 10703503. Hershberger, John (2008), "Improved output-sensitive snap rounding", Discrete and Computational Geometry, 39 (1–3): 298–318, doi:10.1007/s00454-007-9015-0.

References

External links John Hershberger in Scholar Wiki John Hershberger at DBLP Bibliography Server

Worked examples

Example 1 — a first encounter with John Hershberger

Start with the simplest possible case. Write down what John Hershberger claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, 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 John Hershberger 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 John Hershberger 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 John Hershberger

In research: John Hershberger appears in computer science 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 John Hershberger 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: John Hershberger is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1959 births, American computer scientists, California Institute of Technology alumni, so understanding it makes those chapters shorter.
In everyday life: Look for John Hershberger 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 John Hershberger in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what John Hershberger 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 John Hershberger out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is John Hershberger in simple terms?

John E. Hershberger (born 1959) is an American computer scientist and software professional, a principal engineer at Mentor Graphics Corporation since 1993.

Why does John Hershberger matter?

Because it connects several computer science 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 John Hershberger?

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 John Hershberger.