Search results for "Cognitive network"
showing 10 items of 13 documents
Brain-like large scale cognitive networks and dynamics
2018
A new approach to the study of the brain and its functions known as Human Connectomics has been recently established. Starting from magnetic resonance images (MRI) of brain scans, it is possible to identify the fibers that link brain areas and to build an adjacency matrix that connects these areas, thus creating the brain connectome. The topology of these networks provides a lot of information about the organizational structure of the brain (both structural and functional). Nevertheless this knowledge is rarely used to investigate the possible emerging brain dynamics linked to cognitive functions. In this work, we implement finite state models on neural networks to display the outcoming bra…
Altered effective connectivity in drug free schizophrenic patients
2003
The present fMRI study aimed to investigate effective connectivity within a cortical-subcortical-cerebellar information processing network in drug free schizophrenic patients while performing a 2-back working memory task. The finding of enhanced thalamo-cortical and cortico-cortical intrahemispheric connectivity could be interpreted as a compensatory increase of neuronal connection strength consistent with a model of cortical inefficiency in schizophrenic patients. Additionally, the result could be integrated into a model of deficient thalamo-cortical filter functions. Conversely, lower interhemispheric connectivity of the frontal and parietal association cortex appears to be the functional…
Contextual neural-network based spectrum prediction for cognitive radio
2015
Cognitive radio is the technique of effective electromagnetic spectrum usage important for future wireless communication including 5G networks. Neural networks are nature-inspired computational models used to solve cognitive radio prediction problems. This paper presents the use of contextual Sigma-if neural network in prediction of channel states for cognitive radio. Our results indicate that Sigma-if neural network confirms better predictions than Multilayer Perceptron (MLP) network and decreases sensing time for the benefit of the increase of the effectiveness of e-m spectrum usage.
Syntactic Variance and Priming Effects in Translation
2016
The present work investigates the relationship between syntactic variation and priming in translation. It is based on the claim that languages share a common cognitive network of neural activity. When the source and target languages are solicited in a translation context, this shared network can lead to facilitation effects, so-called priming effects. We suggest that priming is a default setting in translation, a special case of language use where source and target languages are constantly co-activated. Such priming effects are not restricted to lexical elements, but do also occur on the syntactic level. We tested these hypotheses with translation data from the TPR database, more specifical…
Knowledge Extraction from Environmental Data Through a Cognitive Architecture
2008
Wireless Sensor Networks represent a novel technology which is expected to experience a dramatic diffusion thanks to the promise to be a pervasive sensory means; however, one of the issues limiting their potential growth relies in the difficulty of managing and interpreting huge amounts of collected data. This paper proposes a cognitive architecture for the extraction of high-level knowledge from raw data through the representation of processed data in opportune conceptual spaces. The presented framework interposes a conceptual layer between the subsymbolic one, devoted to sensory data processing, and the symbolic one, aimed at describing the environment by means of a high level language. T…
Sparsity-aware narrowband interference mitigation and subcarriers selection in OFDM-based cognitive radio networks
2016
In this paper, the performance of an orthogonal frequency division multiplexing overlay cognitive radio network with subcarrier selection schemes is investigated. We propose three subcarrier selection techniques that reduce the level of interference at the primary base station based on collected channel state information from the different network nodes. Approximated outage probability expressions are also derived and verified by simulations for the different studied techniques. In addition, we propose and investigate a new approach for asynchronous narrowband interference (NBI) estimation and mitigation in cognitive radio networks. The proposed approach does not require prior knowledge of …
A Sparsity-Aware Approach for NBI Estimation and Mitigation in Large Cognitive Radio Networks
2016
Underlay cognitive networks should follow strict interference thresholds to operate in parallel with primary networks. This constraint limits their transmission power and eventually the coverage area. Therefore, in this paper, we first design a new approach for asynchronous narrow-band interference (NBI) estimation and mitigation in orthogonal frequency-division multiplexing cognitive radio networks that does not require prior knowledge of the NBI characteristics. Our proposed approach allows the primary user to exploit the sparsity of the secondary users' interference signal to recover it and cancel it based on sparse signal recovery theory. We also propose two subcarrier selection schemes…
Secondary users selection and sparse narrow-band interference mitigation in cognitive radio networks
2018
Spectrum scarcity is a critical problem that may reduce the effectiveness of wireless technologies and services. To address this problem, different spectrum management techniques have been proposed in the literature such as overlay cognitive radio (CR) where the unlicensed users can share the same spectrum with the licensed users. The main challenges in overlay CR networks are the identification and detection of the Primary User (PU) signals in a multi-source narrow-band interference (NBI) scenario. Therefore, in this paper, we investigate the performance of an orthogonal frequency division multiplexing (OFDM) overlay CR network with Secondary Users (SUs) and subcarriers selection schemes. …
Association of Structural Global Brain Network Properties with Intelligence in Normal Aging
2013
Higher general intelligence attenuates age-associated cognitive decline and the risk of dementia. Thus, intelligence has been associated with cognitive reserve or resilience in normal aging. Neurophysiologically, intelligence is considered as a complex capacity that is dependent on a global cognitive network rather than isolated brain areas. An association of structural as well as functional brain network characteristics with intelligence has already been reported in young adults. We investigated the relationship between global structural brain network properties, general intelligence and age in a group of 43 cognitively healthy elderly, age 60–85 years. Individuals were assessed cross-sect…
Supporting code mobility and dynamic reconfigurations over Wireless MAC Processor Prototype
2014
Mobile networks for Internet Access are a fundamental segment of Internet access net- works, where resource optimization are really critical because of the limited bandwidth availability. While traditionally resource optimizations have been focused on high effi- cient modulation and coding schemes, to be dynamically tuned according to the wireless channel and interference conditions, it has also been shown how medium access schemes can have a significant impact on the network performance according to the application and networking scenarios. This thesis work proposes an architectural solution for supporting Medium Access Con- trol (MAC) reconfigurations in terms of dynamic programming and c…