Ing. Viktor Černý

Stať ve sborníku

10.1109/WIMOB55322.2022.9941360

Katedra počítačových systémů

Trust is an essential concept in ad hoc network security. Creating and maintaining trusted relationships between nodes is a challenging task. This paper proposes a decentralized method for evaluating trust in ad hoc networks. The method uses neural networks and local information to predict the trust of neighboring nodes. The method was compared with the original centralized version, showing that even without global information knowledge, the method has, on average, 97% accuracy in classification and 94% in regression problem. An important contribution of this paper is overcoming the main limitation of the original method, which is the centralized evaluation of trust. Moreover, the decentralized method output is a perfect fit to use as an input to enhance routing in ad hoc networks.

Stať ve sborníku

10.1109/ACIT49673.2020.9208818

Katedra počítačových systémů

This article deals with a problem of disconnected wireless sensor networks. Our team investigates a usage of distributed or collaborative beamforming for creation of new long-distance connections between loose network clusters. We focus on decreasing the complexity of searching for network modules which are suitable for creation of inter-cluster connection using distributed/collaborative beamforming techniques.

Článek

10.1007/s11235-013-9839-2

Katedra počítačových systémů

Ad-hoc and sensor networks are a well-studied area which gained a lot of attention in the research in the last decades. Two of the problems of battery-powered radio devices are limited transmitter power and finite amount of energy. This paper continues the path opened by the development of a new technology for radio communication which allows cluster communication beyond the horizon of each individual transmitter and the distribution of power need among the modules forming a cluster. This in terms decreases the average power need per device and contributes to a longer lifetime of the entire network.

Stať ve sborníku

10.1109/NGMAST.2014.58

Katedra počítačových systémů

There are many ways to deal with interference in wireless networks: topology control, scheduling, channel surfing, etc. All try to prevent interference from taking place (by allocating transmissions to different frequencies, to different time slots, etc). The novelty of the proposed approach in this paper is inspired from the way today headphones use noise cancellation – our approach is to use adjacent modules to one transmitter to cancel the signals of that transmitter to desired areas and thus to decrease interference in the network.

Stať ve sborníku

Katedra počítačových systémů

The distributed phase shift beamforming is the great technique for spatial signal filtering in wireless networks. We already showed that this technique can be exploited for the interference reduction in wireless networks. This paper deals with optimal phase shift search for this method.

Stať ve sborníku

Ad-hoc and sensor networks are a well-studied area, which gained a lot of attention in the research in the last decades. Our team proposed a mechanism which enables wireless networks composed by clusters of modules to be connected even when direct relayed communication be- tween clusters is not possible. A cluster is able to transmit as a virtual transmitter beyond the maximal transmission range of individual mod- ules and is able to balance power needed for the transmission between multiple modules having thus multiple sources of energy. The mecha- nism of distributed or collaborative phase-shift beamforming (CPSBF) has one disadvantage: without a-priori known modules position coordi- nates the discovery phase (in which a cluster discovers its neighbouring clusters) has exponential complexity. In this paper we present certain scenarious which can dramatically reduce this complexity.