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Thursday, June 6, 2002

802.11 Wireless Networks: The Definitive Guide

802.11 Wireless Networks: The Definitive Guide. --Matthew Gast examines seven of the most pressing wireless LAN security problems, and potential designs that can mitigate the risks. Matthew is the author of *802.11 Wireless Networks: The Definitive Guide*. [Meerkat: An Open Wire Service]
comments? [] 6:06:22 PM    

re RSS


 Bill Seitz has a new entry on RSS and asks, "What more "interesting" kinds of processing could be done on RSS repositories to make the BlogWeb more "emergent"?"

I "respond" by pointing to this morning's entry re

comments? [] 6:00:48 PM    

Wireless crowding and a solution

A well-described problem  Congestion wears on wireless:  Overlapping networks causing interference

A well-defined solution.   (If only identification of a solution were the same as solving the problem.)

D. P. Satapathy, J. M. Peha, ``Etiquette Modifications For Unlicensed Spectrum: Approach and Impact," 48th IEEE Vehicular Technology Conference (VTC-98). (PDF) Also available in postscript .

Unlicensed spectrum has many benefits. It supports mobility of wireless applications, allows spectrum sharing, and facilitates experimentation and innovation. However, a device may overuse shared spectrum to improve its performance. Such greed is always beneficial for isolated devices. When devices contend for spectrum, greed can also lead to inadequate performance and inefficient spectrum utilization [8,12]. This paper shows that the problem can be solved by modifying the etiquette to include penalty functions that penalize greedy devices. Different penalty functions avoid greed to different degrees.

...Thus, when designing an effective etiquette, there may be tradeoffs between imposing penalties and imposing power limits. Meanwhile, the FCC has increased allocations for unlicensed spectrum. If etiquette modifications are not effected soon, devices meant to operate in isolation may be designed greedy, and the risk of a tragedy of the commons will increase once these products are marketed. It would be prudent for wireless companies to demand etiquette modifications before their competitors market greedy devices...

comments? [] 12:04:12 PM

get notified when this page changes!
Let notify you when this page changes.
This service (or one like it, or some hacker piggybacking on their service (or I?)) ought to rig RSS feeds so that notifications feed into my aggregator rather than into my mailbox.

comments? [] 11:24:53 AM    

Case study on the need for intuitive data visualization motifs

HP does an excellent Kazaa Usability Study [PDF].  Lots of good points:

  • "[Kazaa] presumes that users have perfect knowledge of what kinds of files that are contained in those folders": Know your user. Expection extraction during a usability test and focused interviewing can extract this type of detail.
  •  Recursion is difficult to convey and hierarchies are empirically shown to be a cognitive challenge.  The tree map approach can really nail this issue. Most of the other issues fall into the heuristic "keep the user informed of system status". System status, in this case, relates directly to what is being fetched and what's being offered for fetching.

    The study is also worthy of note for another aspect. It intermingles evaluation techniques very effectively, diagnosing the problem in expert review, proving the existence of the problem by sampling the existing users configuration, and exploring it in depth with traditional testing.

comments? [] 8:59:30 AM    

Palm Evolutionary tree

It would be nice to augment this with sales figures (which could be represented by the thickness of branches and/or by their elevation on the z-axis.


comments? [] 8:37:15 AM    

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