04/2012

VOL. 55 NO. 04

Practice

38 Why LINQ Matters: Cloud Composability Guaranteed The benefits of composability are becoming clear in software engineering.

By Brian Beckman

45 Interactive Dynamics for Visual Analysis

A taxonomy of tools that support the fluent and flexible use of visualizations.

By Jeffrey Heer and Ben Shneiderman

55 CPU DB: Recording Microprocessor History

illustration by alex williamson, illustration by Kentoh/ shutterstocK.com

With this open database, you can mine microprocessor trends over the past 40 years. By Andrew Danowitz, Kyle Kelley, James Mao, John P. Stevenson, and Mark Horowitz

articles’ development led by queue.acm.org

Contributed Articles

64 Sample Size in Usability Studies Magic numbers are strictly hocus-pocus, so usability studies must test many more subjects than is usually assumed.

By Martin Schmettow

71 What Agile Teams Think of Agile Principles

Even after almost a dozen years, they still deliver solid guidance for software development teams and their projects.

By Laurie Williams

Review Articles

77 Probabilistic Topic Models Surveying a suite of algorithms that offer a solution to managing large document archives.

By David M. Blei

86 Putting the ‘Smarts’ into the Smart Grid: A Grand Challenge for Artificial Intelligence A research agenda for making the smart grid a reality. By Sarvapali D. Ramchurn, Perukrishnen Vytelingum, Alex Rogers, and Nicholas R. Jennings

Research Highlights

101 Technical Perspective Building Robust Dynamical Simulation Systems

By Dinesh Manocha

102 Asynchronous Contact Mechanics By David Harmon, Etienne Vouga, Breannan Smith, Rasmus Tamstorf, and Eitan Grinspun

110 Technical Perspective

Who Knows? Searching for Expertise on the Social Web By Ed H. Chi

111 Searching the Village: Models and Methods for Social Search By Damon Horowitz and Sepandar D. Kamvar

about the cover:
to build the smart grid
of the future will require
fundamental rethinking
and reengineering of the
current electricity grid.
indeed, the prospect
of the smart grid poses
a grand challenge for
artificial intelligence,
as explored in this month’s
cover story beginning
on page 86.

Association for Computing Machinery Advancing Computing as a Science & Profession