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Communications of the ACM

Table of Contents


USACM and U.S. Legislation

Computing professionals sometimes find policy issues ill-defined, confusing, or irrelevant. Perhaps that is why — to date — policy participation has been limited within our community.
DEPARTMENT: Letters to the editor

The Halting Problem in the Clear Light of Probability

"Turing's Titanic Machine?" considered Alan Turing's contributions to computability theory, concentrating on the halting problem; that is, decide whether a given program will stop or continue indefinitely. The fact that in …
DEPARTMENT: BLOG@CACM

Protecting Against Data Breaches; Living With Mistakes

Jason Hong writes about security breaches and offers a three-pronged approach. Greg Linden discusses the differences between computers and the human brain and their tolerance of errors.
DEPARTMENT: CACM online

Don't Throw the Baby Out With the Bathwater

Nearly every day I receive an email that includes a link to a new article related to the Open Access movement. I read every one of these articles because I want to understand the different perspectives on the issue so that I …
COLUMN: News

Analyzing Medical Data

Electronic patient records contain a treasure trove of data, and researchers are using natural language processing technology to mine the structured data and free text.

Smarter Photography

Improvements in camera hardware, image processing, camera-photographer interfaces, and image viewing are advancing the state of the art in digital photography.

Data Mining Meets City Hall

Local and national governments are turning to open data to cut their costs, increase transparency and efficiency, and respond to the needs of citizens.

Game changer

Judea Pearl's passionate advocacy of the importance of probability and causality helped revolutionize artificial intelligence.

An Influential Theoretician

Sanjeev Arora, winner of the 2011 ACM-Infosys Award, discusses his pivotal role in theoretical computer science.
COLUMN: The business of software

A Measure of Control

Some limitations on measurements in software.
COLUMN: Inside risks

The Cybersecurity Risk

Increased attention to cybersecurity has not resulted in improved cybersecurity.
COLUMN: Kode Vicious

Scale Failure

Using a tool for the wrong job is OK until the day when it isn't.
COLUMN: Privacy and security

Security of the Internet and the Known Unknowns

Seeking answers to questions about Internet vulnerabilities.
COLUMN: The profession of IT

The Myth of the Elevator Pitch

Instead of pitching, listen and offer.
COLUMN: Viewpoint

Why Computer Scientists Should Care About Cyber Conflict and U.S. National Security Policy

Cybersecurity and policy issues for computer scientists.
SECTION: Practice

A Guided Tour of Data-Center Networking

A good user experience depends on predictable performance within the data-center network.

Modeling People and Places with Internet Photo Collections

Understanding the world from the sea of online photos.

Real-Time Computer Vision with OpenCV

Mobile computer-vision technology will soon become as ubiquitous as touch interfaces.
SECTION: Contributed articles

Why Rumors Spread So Quickly in Social Networks

A few hubs with many connections share with many individuals with few connections.

Trust Extension for Commodity Computers

A user's trust in a single device can be extended to many other devices.
SECTION: Review articles

Data Services

Exploring the technology trends in basic, integrated, and cloud data services.

The GCT Program Toward the P vs. NP Problem

Exploring the power and potential of geometric complexity theory. View a video of Ketan D. Mulmuley's FOCS 2010 tutorial on geometric complexity theory.
SECTION: Research highlights

Technical Perspective: Reconstructing the Unknown, Balancing Structure and Uncertainty

The problem of estimating or reconstructing an unknown structured object from incomplete, partial, noisy measurements is a fundamental one in scientific and technological applications.

Exact Matrix Completion via Convex Optimization

Suppose that one observes an incomplete subset of entries selected from a low-rank matrix. When is it possible to complete the matrix and recover the entries that have not been seen?

Technical Perspective: The Fox and the Hedgehog

"The fox knows many things, but the hedgehog knows one big thing." Philosophers have used this line, attributed to the ancient Greek poet Archilochus, to capture the notion that a person can be either a generalist or a specialist …

Lightweight Modular Staging: A Pragmatic Approach to Runtime Code Generation and Compiled DSLs

Good software engineering practice demands generalization and abstraction, whereas high performance demands specialization and concretization. These goals are at odds, and compilers only rarely translate expressive high-level …
COLUMN: Last byte

Puzzled: Solutions and Sources

Last month (May 2012) we posted a trio of brainteasers concerning designs on square grids. Here, we offer solutions to all three. How did you do?

Q&A: A Sure Thing

Artificial intelligence pioneer Judea Pearl discusses probability, causation, the calculus of intervention, and counterfactuals.