The so-called second generation P2P file-sharing applications have with no doubt a better performance than the first implementations. The most remarkable difference is due to the file division into smaller pieces, where a receiving peer of any piece automatically becomes a new source to other peers. But a new question arises on how we distribute all the pieces provided by a seed peer to minimize the global and presumably individual download times. In this paper we summarize part of the work we have developed up until now to answer this general question, in particular, we will analyze how close the present second generation P2P file-sharing applications remain from an ideal solution with the theoretical best performance, that is, where all peers are interconnected with each other and all peers have an altruistic behavior always uploading its contents at any chance. Successive modifications of the ideal solution will lead us to more realistic scenarios. We will estimate the performance on each case and finally present the current studies we are carrying out to improve the overall capacity.

Agriculture is the largest user of water worldwide by using about 70 percent of total consumption. The world food production depends on the availability of water, considering factors such as demographic and climate change, so the use of efficient irrigation is necessary to apply the correct amount of water to crops. The traditional irrigation systems generally program their scheme based on measurements made at Class A evaporimeter pan. In this paper an irrigation scheme defined by an algorithm that automates the amount of water supplied is presented, it considers the consumption of habanero pepper crop, and a fuzzy system evaluates the necessary duration of irrigation. The climatic variables considered are temperature, relative humidity, and soil moisture. The algorithm was programmed in a microcontroller Atmel 328p included in Arduino platform, with the addition of a ZigBee wireless system that allows for monitoring through a PC. The climatic variables were inserted into the fuzzy system by sets of trapezoidal and triangular form and a Mamdani type inference mechanism in which the knowledge of an expert is registered through the fuzzy rules. The system was applied to a habanero pepper crop at Conkal Institute of Technology in Yucatan, Mexico.

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