AA-lib is a low level gfx library just as many other libraries are. The main difference is that AA-lib does not require graphics device. In fact, there is no graphical output possible. AA-lib replaces those old-fashioned output methods with a powerful ASCII art renderer. The API is designed to be similar to other graphics libraries.
AAFID (Autonomous Agents for Intrusion Detection) is a distributed monitoring architecture with an orientation towards Intrusion Detection developed at the CERIAS at Purdue University. AAFID2 is a prototype implementation of the architecture that includes several ready-to-work agents, plus development facilities for writing your own.
ABC Path Solver is a Perl program and library that automatically solves an ABC Path game while giving the reasoning. ABC Path is a puzzle game in which one should position the letters from "A" to "Y" in a 5*5 grid based on clues. It is featured in brainbashers.com. ABC Path Solver uses a mixture of deduction and solving by trying several branches, which should allow it to solve all initial boards.
ACCORD is a C library for composition of SEM or scanning helium-ion microscope images with correction of drift. It is able to compose (average) large sets of extremely noisy images that were acquired by scanning charged-particle microscopes at the highest possible speeds (lowest pixel-dwell times). If the images are composed using traditional techniques, they usually become extensively blurry. The technique that is implemented in this software corrects these derogations by pre-shifting the composed frames.
ACFTools is a utility for manipulating X-Plane flight simulator aircraft and weapon models without using its Plane Maker. It can decode both Apple and Intel ACF/WPN formats into plain text files with a syntax similar to C, which can be edited and then re-converted into binary data. It is able to extract almost complete 3D models of aircraft (fuselage, floats, tanks, wings, stabs, propellers, engines) and write it in AC3D modeler format. Edited 3D parts can then be merged into plain text and consequently converted into binary ACF files.
ACL2 is a mathematical logic, programming language, and mechanical theorem prover based on the applicative subset of Common Lisp. It is an "industrial-strength" version of the NQTHM or Boyer/Moore theorem prover, and has been used for the formal verification of commercial microprocessors, the Java Virtual Machine, interesting algorithms, and so forth.