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2.
Chaos ; 34(5)2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38781106

RESUMO

The brain is a complex network, and diseases can alter its structures and connections between regions. Therefore, we can try to formalize the action of diseases by using operators acting on the brain network. Here, we propose a conceptual model of the brain, seen as a multilayer network, whose intra-lobe interactions are formalized as the diagonal blocks of an adjacency matrix. We propose a general and abstract definition of disease as an operator altering the weights of the connections between neural agglomerates, that is, the elements of the brain matrix. As models, we consider examples from three neurological disorders: epilepsy, Alzheimer-Perusini's disease, and schizophrenia. The alteration of neural connections can be seen as alterations of communication pathways, and thus, they can be described with a new channel model.


Assuntos
Encéfalo , Modelos Neurológicos , Rede Nervosa , Humanos , Encéfalo/fisiopatologia , Rede Nervosa/fisiopatologia , Doenças do Sistema Nervoso/fisiopatologia , Epilepsia/fisiopatologia , Esquizofrenia/fisiopatologia , Doença de Alzheimer/fisiopatologia
3.
Sensors (Basel) ; 21(22)2021 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-34833729

RESUMO

In the present paper, we investigate the performance of the simultaneous wireless information and power transfer (SWIPT) based cooperative cognitive radio networks (CCRNs). In particular, the outage probability is derived in the closed-form expressions under the opportunistic partial relay selection. Different from the conventional CRNs in which the transmit power of the secondary transmitters count merely on the aggregate interference measured on the primary networks, the transmit power of the SWIPT-enabled transmitters is also constrained by the harvested energy. As a result, the mathematical framework involves more correlated random variables and, thus, is of higher complexity. Monte Carlo simulations are given to corroborate the accuracy of the mathematical analysis and to shed light on the behavior of the OP with respect to several important parameters, e.g., the transmit power and the number of relays. Our findings illustrate that increasing the transmit power and/or the number of relays is beneficial for the outage probability.


Assuntos
Algoritmos , Redes de Comunicação de Computadores , Cognição , Método de Monte Carlo , Probabilidade
4.
Sensors (Basel) ; 20(3)2020 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-32046172

RESUMO

Security performance and the impact of imperfect channel state information (CSI) in underlay cooperative cognitive networks (UCCN) is investigated in this paper. In the proposed scheme, relay R uses non-orthogonal multiple access (NOMA) technology to transfer messages e 1 , e 2 from the source node S to User 1 (U 1 ) and User 2 (U 2 ), respectively. An eavesdropper (E) is also proposed to wiretap the messages of U 1 and U 2 . The transmission's security performance in the proposed system was analyzed and performed over Rayleigh fading channels. Through numerical analysis, the results showed that the proposed system's secrecy performance became more efficient when the eavesdropper node E was farther away from the source node S and the intermediate cooperative relay R. The secrecy performance of U 1 was also compared to the secrecy performance of U 2 . Finally, the simulation results matched the Monte Carlo simulations well.

5.
Sensors (Basel) ; 18(5)2018 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-29738453

RESUMO

Nowadays, the research on vehicular computing enhanced a very huge amount of services and protocols, aimed to vehicles security and comfort. The investigation of the IEEE802.11p, Wireless Access in Vehicular Environments (WAVE) and Dedicated Short Range Communication (DSRC) standards gave to the scientific world the chance to integrate new services, protocols, algorithms and devices inside vehicles. This opportunity attracted the attention of private/public organizations, which spent lot of resources and money to promote vehicular technologies. In this paper, the attention is focused on the design of a new approach for vehicular environments able to gather information during mobile node trips, for advising dangerous or emergency situations by exploiting on-board sensors. It is assumed that each vehicle has an integrated on-board unit composed of several sensors and Global Position System (GPS) device, able to spread alerting messages around the network, regarding warning and dangerous situations/conditions. On-board units, based on the standard communication protocols, share the collected information with the surrounding road-side units, while the sensing platform is able to recognize the environment that vehicles are passing through (obstacles, accidents, emergencies, dangerous situations, etc.). Finally, through the use of the GPS receiver, the exact location of the caught event is determined and spread along the network. In this way, if an accident occurs, the arriving cars will, probably, avoid delay and danger situations.

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