Here are my research publications, ordered by date. The themes are: Artificial Intelligence, Robotics, CAPTCHA, Potential Fields, Human-Computer Interfaces, Image Processing, Society and Law, Methodology, Digital Forensics, Steganography.

You can download BibTEX electronic citation information for all my papers here.

I have previously published as: "Graeme Bell", "Graeme B. Bell" & "Graeme Baxter Bell".

"Strengthening CAPTCHA-based Web security"
Graeme Baxter Bell, First Monday, 17 (2-6): 33, February 2012.

Summary: How to make any CAPTCHA more resistant to computer attacks without being harder for humans.
Keywords: Artificial Intelligence, CAPTCHA.
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"Digital Whistleblowing in Restricted Environments"
Graeme B. Bell. Journal of Digital Information, 12 (3): July 2011.

Summary: How can a whistleblower expose illegal activity from a restricted office environment?
Keywords: Society and Law, Whistleblowers, Fingerprinting, Digital Forensics.
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"A New CAPTCHA Interface Design for Mobile Devices"
Rosa Lin, Shih-Yu Huang, Graeme B. Bell, and Yeuan-Kean Lee. In: Australasian User Interface Conference, Australasian Computer Science Week (ACSW2011), Perth, Australia, and ACM digital library, 2011.

Summary: A new, secure, and user-friendly approach to graphical CAPTCHAs that is resistant to machine learning and image-recognition approaches, and is suitable for mobile devices.
Keywords: CAPTCHA, HCI, Artificial Intelligence.
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"Solid State Drives: The Beginning of the End for Current Practice in Digital Forensic Recovery?"
Graeme B Bell, Richard Boddington. Journal of Digital Forensics, Security and Law, 5 (3): December 2010.

Summary: SSDs can behave autonomously in a way that hard drives do not, which makes present forensic treatment of computer storage outdated and unreliable. This paper explains how SSDs are different from hard drives, and why this matters.
Keywords: Digital Forensics, Society and Law, digital evidence, self-contamination, solid-state drive, SSD, garbage collection.
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"A method for automatic identification of signatures of steganography software"
Graeme B. Bell and Yeuan-Kuen Lee. IEEE Transactions on Information Forensics and Security, 5 (2): 354-358, Jun 2010.

Summary: Binary fingerprinting is amazingly effective against many steganography programs.
Keywords: Steganalysis, Steganography, Artificial Intelligence, Image Processing, Digital Forensics.
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"The dangers of webcrawled datasets"
Graeme Bell. First Monday, 15 (2): February 2010.

Summary: Gathering bulk data via the web can lead to practical, ethical & legal problems for scientists.
Keywords: Methodology, Society and Law, Steganography, Image Processing, Scientific Methodology, Internet, World Wide Web, Digital Forensics.
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"An Efficient Segmentation Algorithm for CAPTCHAs with Line Cluttering and Character Warping"
Shih-Yu Huang, Yeuan-Kuen Lee, Graeme B. Bell, and Zhan-he Ou. Multimedia Tools and Applications, 48 (2): 267-289, 2010.

Summary: An efficient image-processing technique for breaking various types of CAPTCHAs.
Keywords: CAPTCHA, Segmentation, Recognition, Turing test, Image Processing, Artificial Intelligence.
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"An Advanced Least-Significant-Bit Embedding Scheme for Steganographic Encoding"
Yeuan-Kuen Lee, Graeme Bell, Shih-Yu Huang, Ran-Zan Wang, and Shyong Jian Shyu. In Advances in Image and Video Technology (PSIVT2009), Tokyo, Japan, LNCS 5414, pages 349-360. 2009.

Summary: A technique for distributing steganographic LSB data that looks statistically similar to natural data LSB distribution. It resists the well-known Chi-square and RS steganalysis attacks.
Keywords: Steganography.
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"A Projection-based Segmentation Algorithm for Breaking MSN and YAHOO CAPTCHAs"
Shih-Yu Huang, Yeuan-Kuen Lee, Graeme B. Bell, and Zhan-He Ou. In Proceedings of the 2008 International Conference of Signal and Image Engineering (ICSIE'08), London, UK, pages 1-. Jul 2008.

Summary: An improved segmentation algorithm for attacking MSN/Yahoo CAPTCHAs.
Keywords: CAPTCHA breaking, segmentation, recognition, CAPTCHA, Image Processing, Artificial Intelligence.
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"The Existence of Local Minima in Local-Minimum-Free Potential Surfaces"
Graeme B. Bell and Michael Livesey. In: Towards Autonomous Robotic Systems (TAROS 2005), London, UK, 2005.

Summary: There are mathematical objects that behave like local minima but which do not conform to the normal ideas of local minima. This is particularly important for techniques that rely on minima-detection heuristics.
Keywords: Artificial Intelligence, Potential Fields, Local Minimum, Navigation, Robotics, Computer Games.
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"Forward Chaining for Potential Field Based Navigation"
Graeme B. Bell. PhD thesis, University of St Andrews, 2005 .

Summary: My PhD! :-) A general introduction to navigation, potential fields and a new fast, simple potential field technique for navigation in robotics and computer games. It doesn't rely on minima-free fields (inefficient) or random behaviour (inefficient, unreliable), and doesn't make reference to any information outside the potential field. The family of techniques is based on a modified discrete gradient descent algorithm.
Keywords: Artificial Intelligence, Navigation, Potential Fields, Robotics, Computer Games, Local Minimum, Cinematic Agents.
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"Agent Navigation Using Potential Fields and Forward Chaining"
Graeme B. Bell and Michael Weir. In PREP 2004 Postgraduate Research Conference in Electronics, Photonics, Communications and Networks and Computing Science. 2004.

Summary: Increasingly competent heuristics produce the novel Forward Chaining heuristic, allowing navigation past obstacle configurations that are impossible for traditional potential field methods.
Keywords: Artificial Intelligence, Navigation, Potential Fields, Robotics, Computer Games, Local Minimum.
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"Forward Chaining for Robot and Agent Navigation using Potential Fields"
Graeme B. Bell and Michael Weir. In 27th Australasian Computer Science Conference (ACSC2004), Dunedin, New Zealand. 2004.

Summary: Introducing a fast, efficient potential fields-based navigation technique that isn't vulnerable to the local minima problem in navigation. Suitable for robots and games.
Keywords: Artificial Intelligence, Navigation, Potential Fields, Robotics, Computer Games, Local Minimum.
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"The Incorporation of Intentional Action into Robots"
Michael Weir and Graeme B. Bell. School of Computer Science, University of St Andrews. 2001.

Summary: How does a robot become able to act intentionally?
Keywords: Robotics, Behaviour, Determinacy, Plasticity, Potential Fields, Artificial Intelligence.
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