Sign In

Communications of the ACM

Letters to the editor

What Role For Computer Science in the War on Terror?

letters to the editor illustration


The Contributed Article "The Topology of Dark Networks" by Jennifer Xu and Hsinchun Chen (Oct. 2008) ignored sensitive cultural issues while addressing a subject that might by itself offend some people in Muslim societies, including those in the Middle East. The software system it described for fighting what some might call "Islamic terrorism" represents a highly charged political subject. A more appropriate place to publish would have been in a publication sponsored by, say, the U.S. Department of Defense, Central Intelligence Agency, or Federal Bureau of Investigation. ACM, which claims to be independent, with a clear mission to advance computer science while being open to members from around the world and free of geographic, ethnic, religious, or political affiliations, should stick to this mission and not involve itself in the so-called War on Terror.

Science is a universal language that should be used to bridge gaps between cultures, promote understanding and cooperation, and avoid worsening damage caused by politicians who push the world toward trouble. ACM should not take on such a sensitive subject that only increases tensions and does not make the world a better place.

This is my personal opinion. I would not seek to impose it on or cause offense to anyone.

Othman El Moulat, Rabat, Morocco

Xu Responds:

We apologize if our article appeared to be targeting particular groups. This was certainly not our intent. Our research tried to address the new Dark Network phenomenon using selected examples and available datasets. Our hope is to develop advanced, science-based, data-driven intelligence and security-informatics techniques that help analyze and understand illicit covert communication and interaction networks. We agree that computing research should not be used for political purposes. We also hope that our research supports the study and understanding of deeply complex social phenomena.

Jennifer Xu, Waltham, MA
Hsinchun Chen, Tucson, AZ

What Gates's Most Enduring Legacy Should Be

Michael Cusumano's Viewpoint column "Technology Strategy and Management" on "The Legacy of Bill Gates" (Jan. 2009) displayed a rather stunning values system by saying that "grow[ing] the PC software business... should be Gates' most enduring legacy." This is not a prediction of what will be Gates's most enduring legacy, though on this issue I would differ as well. Rather, it is a normative statement of what should be his most enduring legacy. Does Cusumano really hope that the massive changes now under way in international public health will not endure? His conclusion should not have been so surprising after he referred to Gates's philanthropy as "highly laudable" but only in the context of bemoaning what a distraction it had become from his business interests. I still found my jaw dropping at the word "should."

Max Hailperin, St. Peter, MN

NP-Completeness Not the Same as Separating P from NP

In his news story "The Limits of Computability" (Nov. 2008) David Lindley wrote: "Showing that a problem is NP-complete means proving that no known algorithm can solve it in polynomial time."

In fact, saying that a problem is NP-complete means only that it is "as hard as" any other problem in NP. Lindley apparently confused the definition of NP-completeness with the problem of separating P from NP. Such an error may be pardoned, even overlooked, in the science columns of a general-interest newspaper or magazine, but not in Communications.

Madhavan Mukund, Chennai, India

Lindley Responds:

Mukund is correct; this was a slip-up, though one that's easily rectified.

In its earlier paragraphs, the story defined an NP problem as one for which no polynomial-time solution is known, then explained the distinction between NP and NP-complete, but in introducing the unresolved question of whether P and NP are truly distinct, I should have referred to NP problems generally, not NP-complete problems in particular. With this in mind, the paragraph in question would read correctly.

David Lindley, Alexandria, VA

Back to Top


Communications welcomes your opinion. To submit a Letter to the Editor, please limit your comments to 500 words or less and send to


©2009 ACM  0001-0782/09/0400  $5.00

Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, to republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee.

The Digital Library is published by the Association for Computing Machinery. Copyright © 2009 ACM, Inc.


No entries found

Sign In for Full Access
» Forgot Password? » Create an ACM Web Account
Article Contents: