Can Punctured Rate-1/2 Turbo Codes Achieve a Lower Error Floor than their Rate-1/3 Parent Codes?

In this paper we concentrate on rate-1/3 systematic parallel concatenated convolutional codes and their rate-1/2 punctured child codes. Assuming maximum-likelihood decoding over an additive white Gaussian channel, we demonstrate that a rate-1/2 non-systematic child code can exhibit a lower error floor than that of its rate-1/3 parent code, if a particular condition is met. However, assuming iterative decoding, convergence of the non-systematic code towards low bit-error rates is problematic. To alleviate this problem, we propose rate-1/2 partially-systematic codes that can still achieve a lower error floor than that of their rate-1/3 parent codes. Results obtained from extrinsic information transfer charts and simulations support our conclusion.Comment: 5 pages, 7 figures, Proceedings of the 2006 IEEE Information Theory Workshop, Chengdu, China, October 22-26, 200

Cost calculations, religion and commerce: the Book of Good Government of the Souk of Malaga in the 13th Century

This paper analyzes the cost calculations in the 13th Century Book of Good Government of a Souk (Zoco), written by Al-Saqati and dealing with the Malaga souk. This helps us to appreciate the historical accounting patrimony of al-Andalus and to consider the influence of religious doctrine on cost procedure. We inquire into the genesis of complex cost accounting techniques by considering their social, political, and cultural inspiration and not their hitherto strictly economic rationality. The study provides evidence of the following peculiarities: the price fixing related to retail commercial activities, aimed to avoid fraud and was in defense of the final consumer, and was above all, supported by a religious motivation.innovation, imitation, proactivity, risk taking, customer and competitors focus, competitiveness.