Immortalitat

Els humans sempre hem buscat la immortalitat, i potser de tant buscar-la en- cara no ens hem adonat que ja en som. Bé, de fet, com a persones individuals, no som pas immortals, però els nostres gens si que ho són. El raonament és molt simple: si tots els éssers vius descendim d'un mateix ancessor, tots haurem heretat característiques d'ell, codificades al material genètic. Per tant, en tots nosaltres sobreviuen característiques d'aquell reeixit intent vital primigeni, de la mateixa manera que en els nostres descendents, siguin humans o pertanyin a qualsevol altra espècie humanoide successora nostra que la selecció natural afavoreixi, si es dóna el cas, sobreviuran els nostres gens, assegurant-nos la immortalitat genètica [...].

A Fair and Secure Cluster Formation Process for Ad Hoc Networks

An efficient approach for organizing large ad hoc networks is to divide the nodesinto multiple clusters and designate, for each cluster, a clusterhead which is responsible forholding intercluster control information. The role of a clusterhead entails rights and duties.On the one hand, it has a dominant position in front of the others because it manages theconnectivity and has access to other node¿s sensitive information. But on the other hand, theclusterhead role also has some associated costs. Hence, in order to prevent malicious nodesfrom taking control of the group in a fraudulent way and avoid selfish attacks from suitablenodes, the clusterhead needs to be elected in a secure way. In this paper we present a novelsolution that guarantees the clusterhead is elected in a cheat-proof manner.

Review of Robust Cooperative Spectrum Sensing Techniques for Cognitive Radio Networks

Cognitive radio networks sense spectrum occupancy and manage themselvesto operate in unused bands without disturbing licensed users. The detection capability of aradio system can be enhanced if the sensing process is performed jointly by a group of nodesso that the effects of wireless fading and shadowing can be minimized. However, taking acollaborative approach poses new security threats to the system as nodes can report falsesensing data to reach a wrong decision. This paper makes a review of secure cooperativespectrum sensing in cognitive radio networks. The main objective of these protocols is toprovide an accurate resolution about the availability of some spectrum channels, ensuring thecontribution from incapable users as well as malicious ones is discarded. Issues, advantagesand disadvantages of such protocols are investigated and summarized.