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Important inference problems in statistical physics, computer vision, error-correcting coding theory, and artificial intelligence can all be reformulated as the computation of marginal probabilities on factor graphs. The belief propagation (BP) algorithm is an efficient way to solve these problems that is exact when the factor graph is a tree, but only(More)
This is an updated and expanded version of TR2000-26, but it is still in draft form. Belief propagation (BP) was only supposed to work for tree-like networks but works surprisingly well in many applications involving networks with loops, including turbo codes. However, there has been little understanding of the algorithm or the nature of the solutions it(More)
Cooperative communications, where parallel relays forward information to a destination node, can greatly improve the energy efficiency and latency in ad-hoc networks. However, current networks do not fully exploit its potential, as they only use traditional energy-accumulation, which is often used in conjunction with repetition coding or cooperative(More)
We describe a novel approach for computing collision-free global trajectories for p agents with specified initial and final configurations, based on an improved version of the alternating direction method of multipliers (ADMM). Compared with existing methods, our approach is naturally parallelizable and allows for incorporating different cost functionals(More)
We study the performance of the newly invented rateless codes (LT-and Raptor codes) on noisy channels such as the BSC and the AWGN channel. We find that Raptor codes outperform LT codes, and have good performance on a wide variety of noisy channels. This work may not be copied or reproduced in whole or in part for any commercial purpose. Permission to copy(More)
We describe a hill-climbing algorithm that constructs high-girth quasi-cyclic low density parity check (QC-LDPC) codes. Given a desired girth, the algorithm can find QC-LDPC codes of shorter block-length in much less time compared with the previously proposed " guess-and-test " algorithm. An analysis is also provided to explain when guess-and-test would be(More)
Construction toys are a superb medium for geometric models. We argue that such toys, suitably instrumented or sensed, could be the inspiration for a new generation of easy-to-use, tangible modeling systems—especially if the tangible modeling is combined with graphical-interpretation techniques for enhancing nascent models automatically. The three key(More)
We describe a method to encode fingerprint biometrics securely for use, e.g., in encryption or access control. The system is secure because the stored data does not suffice to recreate the original fingerprint biometric. Therefore, a breach in database security does not lead to the loss of biometric data. At the same time the stored data suffices to(More)