Ing. Alexandru Moucha, Ph.D.

Stať ve sborníku

10.1109/ACIT52158.2021.9548546

Katedra počítačových systémů

With the world becoming more mobile and dynamic each year, the application of ad-hoc networks has broadened. Ad-hoc networks do not have a predefined infrastructure; each node serves as a router, bringing security challenges. Trust and trustworthiness mechanisms are among the most common methods for ensuring security in an ad-hoc network. In [1], we proposed a method for the evaluation of trust in ad-hoc networks. This paper aims to describe the method formally and analyze its performance. The original paper showed that neural networks could do trust estimation with an average 98% accuracy of the classification and 94% of the regression problem. This paper aims to investigate the capabilities of our method under malicious conditions. The analysis could also provide insight for tuning trust parameters, such as the threshold of trust. Furthermore, this paper presents a mathematical model behind the problem to show that the neural network approach is reasonable.

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.

Stať ve sborníku

10.1109/IWCMC.2017.7986315

Katedra počítačových systémů

In this paper, we demonstrate that neural networks (NNs) are capable of trust estimation and evaluation in ad-hoc networks. The concept of trust in distributed systems arose from the notion of social trust. By the trust problem, we understand the problem of measuring the confidence in the fact that individual nodes behave correctly. We model trust in ad-hoc networks using the packet delivery ratio (PDR) metric. We have developed a method to apply NNs for solving the trust problem in ad-hoc networks. We have conducted a series of simulation experiments and measured the quality of our new method. The results show in average 98% accuracy of the classification and 94% of the regression problem. An important contribution of our research is a verification of the hypothesis that synthetic generation of ad-hoc network traffic in a simulator is sufficient for training of a NN that is then capable to accurately estimate trust in an ad-hoc network.

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

Katedra počítačových systémů

The area of interfering radio waves has been studied thoroughly when the antennas are powered by the same radio chip (smart antennas, MIMO, antenna arrays, etc.), however the science of achieving good results in a distributed manner (one antenna per device) and over multiple layers in the communication stack (e. g. routing tables based on radio wave interference) is still in its infancy. The work of the authors is exactly to explore this realm of phase-shift interfering waves and this paper brings into attention the possibility of cluster discovery that will proceed communication between two clusters through phase-shift distributed beamforming.