Large Scale WSN deployment is considered to be a very complex operation in terms of both efficiency and cost. Sensor cost has never been low, not even today, though at the same time the large areas to be covered call for a huge number of wireless sensors. The complexity escalates when it comes to forest areas, as such areas consist of an assortment of different landscapes and terrains and therefore, they cannot be modeled in detail. In this paper a first approach to forest area classification is attempted, so that simulation models can describe the attenuation of the alarming signal and the corresponding connectivity in the classified area. A number of models produced by Shawn simulator are provided, for forest areas with dense and scant plantation of trees. The model that best converges to the real experiment metrics per area is determined and is therefore referenced as “the model” for the specific classified area. Provided the fact that the simulation model per classified area is granted, a step to the optimal sensor topology is performed, as the connectivity and path loss problem is mainly and in most cases linearly confined to distance variations. Recent Patents are also covered. The simulation models along with optimal sensor topologies can become a guide in Large Scale WSN deployment primarily for the areas classified as “dense” and “scant” in terms of plantation, with the aim to deploy a reliable WSN for environmental purposes.
This paper provides a review on patents linked with low-profile Ultrawideband (UWB) antennas in the last decade for broadband communications. Six selected patents on this topic including tapered slot antennas with reduced profile, planar dipole antennas with flat reflector and planar slot antennas with flat reflector are highlighted and discussed in detail. The trend of using structural compensation instead of using absorbing loads at the end of feeding lines or at the body of antennas is rather obvious for improved antenna efficiencies as well as reduced fabrication costs. At the same time, difficulties of impedance matching encountered for structural compensation and reduced profile are partly overcome by using new structural mechanisms, such as the coupled feeding schemes, inductance loaded structures and compact baluns. These noticeable progresses on this topic could play an important role in the development of various broadband communications and other broadband applications.
One of the most relevant problem for an Internet Service Provider is the large bandwidth usage on international links, mainly due to peer-to-peer applications adopted for file-sharing. The Collaborative Locality-aware Overlay SERvice (CLOSER) technology has been recently proposed to solve this issue by properly modifying the behavior of peer-to-peer application. The technology is also covered in two recent patent applications. This paper presents possible design guidelines to actually implement CLOSER in a DHT-based peer-to-peer system and describe a real implementation based on the popular aMule application.
In this article we present a short survey of representative milestones achieved during last years on the control and managementof optical transport networks, and discuss their main characteristics and potential impact on the future.It is worth noting that this survey does not try to enumerate all the existing research topics and patents. Instead, it focuses on a representative subset and tries to relate them to a few important ongoing research topics. Concerning patents, some inventions from important companies such as Nippon Telegraph and Telephone Corp., Futurewei Technologies, Inc., Hitachi Ltd., Huawei Technologies Co., or Tellabs Operations Inc. are reviewed. As deployment of these advanced networks seems to be imminent, all of these companies show a great interest in being well positioned. Finally, selected still open research issues are also introduced and expected near term contributions are devised.
With the growth of multimedia services over wireless systems, the security of communication over cellular mobile phone networks, wireless access networks, and unreliable mobile ad-hoc networks is becoming a challenging issue. Secure communication implies data confidentiality and integrity, along with authentication, bringing with it commercial viability and protection of intellectual property. Innovatory key management protocols, specialized for multimedia exchange, are now under active development. Such protocols accelerate the key management process in order not to introduce additional latency, especially at start-up time, to what are real-time services. Whereas encryption algorithms are, for reasons of open scrutiny and validation, not a subject of confidentiality, a shared secret, the session key, must be confidential and that session key relies on the existence of a secret permanent key. If a server can successfully distribute keys to remote clients without interception, the greater becomes the chance of secure communication, even though no side channel and no physical exchange of keys are required. Therefore, the focus of this review is to highlight: the key generation mechanisms, interaction with associated key management protocols; and the strength of key-management protocols against security attacks. In addition, the paper reviews recent patents on multimedia key management and also examines counter-measures present in key-management protocols against known key and data attacks.
This article provides a detailed discussion of the different algorithms used in solving the Channel Assignment Problem. The authors provide a survey of a large number of published papers in the area of Channel Allocation Problems and describe the different methods used from the early 70s till now. The algorithms can be broadly categorized in terms of Local Search, Simulated Annealing, Graph Theory, Neural Networks, Genetic Algorithms and Tabu Search. Also in this paper we refer to some patents that have been recently acquired in the field of mobile communication and evolutionary algorithms.