5 research outputs found
Distributed architecture for resource description and discovery in the IoT
Nowadays, the Internet of Things (IoT) creates a vast ecosystem of
intelligent objects interconnected via the Internet, allowing them to exchange
information and to interact. This paradigm has been extended to a new concept,
called the Web of Things (WoT), considering that every physical object can be
accessed and controlled using Web-based languages and protocols, such as: the
CoAP protocol which is becoming the most accepted and suitable protocol in this
context. Moreover, the architectures currently proposed for the creation of IoT
environments lack efficient and standard support for the discovery, selection
and composition of IoT services and their integration in a scalable and
interoperable way. To overcome this, in this work, we propose a hybrid and
distributed CoAP-based architecture, considering all these aspects by combining
the Fog Computing paradigm and structured P2P overlay networks. Furthermore, we
describe the different components of our architecture and explain the
interaction between them
Service discovery and selection in IoT: A survey and a taxonomy
International audienc
Intra-specific morphological variation of the spermatheca in the simultaneously hermaphroditic land snail Helix aperta
In the majority of internally fertilizing animals, females are equipped with sperm storage organs where they store the sperm received during copulation. In many simultaneously hermaphroditic pulmonates, these organs consist of complex spermathecae that show inter- and intra-specific variation in their structure. This variability is theoretically predicted by postcopulatory sexual selection in the context of sperm competition and cryptic female choice. In this study, the variation in the structure of the spermatheca was investigated in the land snail Helix aperta from four natural populations near Bejaia in northern Algeria. The populations were different in local snail density, probably also reflecting the intensity of sperm competition. We tested whether the spermatheca showed differences that are predicted by sperm competition theory. In addition, we tested whether the spermathecal structure depends on the shell size and/or is correlated with other reproductive organs that are thought to be affected by sexual selection. We found that the fertilization pouch of H. aperta consists of a simple fertilization chamber and 3–9 spermathecal tubules. The four populations did not differ significantly in the mean number of these tubules. However, significant differences were found in the length of the main tubule, the length of the fertilization chamber, and the average length of lateral tubules. In addition, strong associations were detected between the lengths of these structures and the local snail density, while no effect of shell size or reproductive organs was found. Our results indicate that the intensity of sperm competition may not affect the total number of spermathecal tubules, but may increase their lengths. This increase in spermathecal length may reflect an improved sperm storage capacity that is probably beneficial in situations of high sperm competitions intensity