11/08

VOL. 51 NO. 11

Contributed Art icles

54 A Tribute to Jim Gray

We knew him as both scholar and friend.

By Michael Stonebraker and David J. De Witt

58 Jim Gray, Astronomer

How he helped develop the SkyServer, delivering computation directly to terabytes of astronomical data.

By Alexander S. Szalay

photoGraph by Joel bartlett, nexus friend Grapher by ivan KoziK

about the cover: the portrait of Jim Gray was done by illustrator Jeffrey smith, a professor at the art Center College of design, pasadena, Ca. his work has been recognized with awards from the new york society of illustrators, the society of newspaper design, the society of publications designers, Communication arts, among others. for more, see http://jeffreysmithillustrator.com/.

Review Articles
Virtual Extension

as with all magazines, page limitations often prevent the publication of articles that might otherwise be included in the print edition. to ensure timely publication, aCm created Communications’ virtual extension (ve).

ve articles undergo the same rigorous review process as those in the print edition and are accepted for publication on their merit. these articles are now available to aCm members in the digital library.

66 The Convergence of Social and Technological Networks Internet-based data on human interaction connects scientific inquiry like never before.

By Jon Kleinberg

Research Highlights

74 Technical Perspective

The Polaris Tableau System By Jim Gray

75 Polaris: A System for Query, Analysis, and Visualization of Multidimensional Databases By Chris Stolte, Diane Tang, and Pat Hanrahan

85 Technical Perspective Safeguarding Online Information against Failures and Attacks

By Barbara Liskov

86 Zyzzyva: Speculative Byzantine Fault Tolerance

By Ramakrishna Kotla, Allen Clement, Edmund Wong, Lorenzo Alvisi, and Mike Dahlin

SME Strategies: An Assessment of High vs. Low Performers Daesoo Kim, Terence T. Ow, and MinJoon Jun

A European Perspective of VoIP in Market Competition Claudio Feijóo, José Luis Gómez-Barroso, and David Rojo-Alonso

Technology Acceptance and ERP Documentation Usability Judy E. Scott

Conceptual Modeling Windows
and Bounds for Space and Time
in Database Constraints
Faiz Currim and Sudha Ram

User-Centric Services Provisioning
in Wireless Environments
Quan Z. Sheng, Boualem Benatallah,
and Zakaria Maamar

Exploring the Dark Side of IS in Achieving Organizational Agility Dongback Seo and Ariel I. La Paz

Six Strategies for Electronic Medical Records Systems Srinivasan Venkatraman, Hillol Bala, Viswanath Venkatesh, and Jack Bates

Technical Opinion Motivational Affordances: Reasons for ICT Design and Use Ping Zhang

Association for Computing Machinery Advancing Computing as a Science & Profession