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Pesquisa : L01.224.230.110 [Categoria DeCS]
Referências encontradas : 13219 [refinar]
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  1 / 13219 MEDLINE  
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[PMID]:29377904
[Au] Autor:Ajmal H; Khan A; Rehman S; Hussain F; Alam M; Young R
[Ad] Endereço:National University of Sciences and Technology (NUST), Islamabad, Pakistan.
[Ti] Título:Analysis of channel uncertainty in ARQ relay networks.
[So] Source:PLoS One;13(1):e0190622, 2018.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Several power allocation algorithms for cooperative relay networks are presented in the literature. These contributions assume perfect channel knowledge and capacity achieving codes. However in practice, obtaining the channel state information at a relay or at the destination is an estimation problem and can generally not be error free. The investigation of the power allocation mechanism in a wireless network due to channel imperfections is important because it can severely degrade its performance regarding throughput and bit error rate. In this paper, the impact of imperfect channel state information on the power allocation of an adaptive relay network is investigated. Moreover, a framework including Automatic Repeat reQuest (ARQ) mechanism is provided to make the power allocation mechanism robust against these channel imperfections. For this framework, the end-to-end SNR is calculated considering imperfect channel knowledge using ARQ analytically. The goal is to emphasize the impact of imperfect channel knowledge on the power allocation mechanism. In this paper, the simulation results illustrate the impact of channel uncertainties on the average outage probability, throughput, and consumed sum power for different qualities of channel estimation. It is shown that the presented framework with ARQ is extremely robust against the channel imperfections.
[Mh] Termos MeSH primário: Serviços de Informação/estatística & dados numéricos
Tecnologia sem Fio/estatística & dados numéricos
Tecnologia sem Fio/tendências
[Mh] Termos MeSH secundário: Algoritmos
Redes de Comunicação de Computadores
Simulação por Computador
Incerteza
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180226
[Lr] Data última revisão:
180226
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180130
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0190622


  2 / 13219 MEDLINE  
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[PMID]:29352282
[Au] Autor:Liu J; Wu Z; Dong J; Wu J; Wen D
[Ad] Endereço:School of Computer Science and Technology, Harbin Institute of Technology, Harbin, China.
[Ti] Título:An energy-efficient failure detector for vehicular cloud computing.
[So] Source:PLoS One;13(1):e0191577, 2018.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Failure detectors are one of the fundamental components for maintaining the high availability of vehicular cloud computing. In vehicular cloud computing, lots of RSUs are deployed along the road to improve the connectivity. Many of them are equipped with solar battery due to the unavailability or excess expense of wired electrical power. So it is important to reduce the battery consumption of RSU. However, the existing failure detection algorithms are not designed to save battery consumption RSU. To solve this problem, a new energy-efficient failure detector 2E-FD has been proposed specifically for vehicular cloud computing. 2E-FD does not only provide acceptable failure detection service, but also saves the battery consumption of RSU. Through the comparative experiments, the results show that our failure detector has better performance in terms of speed, accuracy and battery consumption.
[Mh] Termos MeSH primário: Computação em Nuvem
Fontes de Energia Elétrica/estatística & dados numéricos
Veículos Automotores/estatística & dados numéricos
[Mh] Termos MeSH secundário: Algoritmos
Redes de Comunicação de Computadores
Falha de Equipamento/estatística & dados numéricos
Seres Humanos
Internet
Energia Solar/estatística & dados numéricos
Integração de Sistemas
[Pt] Tipo de publicação:COMPARATIVE STUDY; EVALUATION STUDIES; JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180226
[Lr] Data última revisão:
180226
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180121
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0191577


  3 / 13219 MEDLINE  
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[PMID]:27775571
[Au] Autor:Aparicio S; Martínez-Garrido MI; Ranz J; Fort R; Izquierdo MÁ
[Ad] Endereço:Instituto de Tecnologías Físicas y de la Información "Leonardo Torres Quevedo" (ITEFI) CSIC, C/Serrano, 144, 28006 Madrid, Spain. sofia.aparicio@csic.es.
[Ti] Título:Routing Topologies of Wireless Sensor Networks for Health Monitoring of a Cultural Heritage Site.
[So] Source:Sensors (Basel);16(10), 2016 Oct 19.
[Is] ISSN:1424-8220
[Cp] País de publicação:Switzerland
[La] Idioma:eng
[Ab] Resumo:This paper provides a performance evaluation of tree and mesh routing topologies of wireless sensor networks (WSNs) in a cultural heritage site. The historical site selected was San Juan Bautista church in Talamanca de Jarama (Madrid, Spain). We report the preliminary analysis required to study the effects of heating in this historical location using WSNs to monitor the temperature and humidity conditions during periods of weeks. To test which routing topology was better for this kind of application, the WSNs were first deployed on the upper floor of the CAEND institute in Arganda del Rey simulating the church deployment, but in the former scenario there was no direct line of sight between the WSN elements. Two parameters were selected to evaluate the performance of the routing topologies of WSNs: the percentage of received messages and the lifetime of the wireless sensor network. To analyze in more detail which topology gave the best performance, other communication parameters were also measured. The tree topology used was the collection tree protocol and the mesh topology was the XMESH provided by MEMSIC (Andover, MA, USA). For the scenarios presented in this paper, it can be concluded that the tree topology lost fewer messages than the mesh topology.
[Mh] Termos MeSH primário: Monitoramento Ambiental/métodos
Tecnologia sem Fio
[Mh] Termos MeSH secundário: Algoritmos
Redes de Comunicação de Computadores
Modelos Teóricos
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180205
[Lr] Data última revisão:
180205
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:161025
[St] Status:MEDLINE


  4 / 13219 MEDLINE  
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[PMID]:29329294
[Au] Autor:Umer MF; Sher M; Bi Y
[Ad] Endereço:Department of Computer Science and Software Engineering, International Islamic University, Islamabad, Pakistan.
[Ti] Título:A two-stage flow-based intrusion detection model for next-generation networks.
[So] Source:PLoS One;13(1):e0180945, 2018.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The next-generation network provides state-of-the-art access-independent services over converged mobile and fixed networks. Security in the converged network environment is a major challenge. Traditional packet and protocol-based intrusion detection techniques cannot be used in next-generation networks due to slow throughput, low accuracy and their inability to inspect encrypted payload. An alternative solution for protection of next-generation networks is to use network flow records for detection of malicious activity in the network traffic. The network flow records are independent of access networks and user applications. In this paper, we propose a two-stage flow-based intrusion detection system for next-generation networks. The first stage uses an enhanced unsupervised one-class support vector machine which separates malicious flows from normal network traffic. The second stage uses a self-organizing map which automatically groups malicious flows into different alert clusters. We validated the proposed approach on two flow-based datasets and obtained promising results.
[Mh] Termos MeSH primário: Redes de Comunicação de Computadores
Modelos Teóricos
[Mh] Termos MeSH secundário: Algoritmos
Máquina de Vetores de Suporte
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1801
[Cu] Atualização por classe:180129
[Lr] Data última revisão:
180129
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180113
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0180945


  5 / 13219 MEDLINE  
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[PMID]:29315302
[Au] Autor:Alheeti KMA; Al-Ani MS; McDonald-Maier K
[Ad] Endereço:School of Computer Sciences and Electronic Engineering University of Essex, Colchester, United Kingdom.
[Ti] Título:A hierarchical detection method in external communication for self-driving vehicles based on TDMA.
[So] Source:PLoS One;13(1):e0188760, 2018.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Security is considered a major challenge for self-driving and semi self-driving vehicles. These vehicles depend heavily on communications to predict and sense their external environment used in their motion. They use a type of ad hoc network termed Vehicular ad hoc networks (VANETs). Unfortunately, VANETs are potentially exposed to many attacks on network and application level. This paper, proposes a new intrusion detection system to protect the communication system of self-driving cars; utilising a combination of hierarchical models based on clusters and log parameters. This security system is designed to detect Sybil and Wormhole attacks in highway usage scenarios. It is based on clusters, utilising Time Division Multiple Access (TDMA) to overcome some of the obstacles of VANETs such as high density, high mobility and bandwidth limitations in exchanging messages. This makes the security system more efficient, accurate and capable of real time detection and quick in identification of malicious behaviour in VANETs. In this scheme, each vehicle log calculates and stores different parameter values after receiving the cooperative awareness messages from nearby vehicles. The vehicles exchange their log data and determine the difference between the parameters, which is utilised to detect Sybil attacks and Wormhole attacks. In order to realize efficient and effective intrusion detection system, we use the well-known network simulator (ns-2) to verify the performance of the security system. Simulation results indicate that the security system can achieve high detection rates and effectively detect anomalies with low rate of false alarms.
[Mh] Termos MeSH primário: Condução de Veículo
Comunicação
Redes de Comunicação de Computadores
Segurança Computacional
[Mh] Termos MeSH secundário: Algoritmos
Análise por Conglomerados
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Em] Mês de entrada:1801
[Cu] Atualização por classe:180129
[Lr] Data última revisão:
180129
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180110
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0188760


  6 / 13219 MEDLINE  
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[PMID]:29267299
[Au] Autor:Zhao Q; Zhang C; Zhao Z
[Ad] Endereço:Computer Science and Technology College, Jilin University, Changchun, Jilin, China.
[Ti] Título:SCM: A method to improve network service layout efficiency with network evolution.
[So] Source:PLoS One;12(12):e0189336, 2017.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Network services are an important component of the Internet, which are used to expand network functions for third-party developers. Network function virtualization (NFV) can improve the speed and flexibility of network service deployment. However, with the evolution of the network, network service layout may become inefficient. Regarding this problem, this paper proposes a service chain migration (SCM) method with the framework of "software defined network + network function virtualization" (SDN+NFV), which migrates service chains to adapt to network evolution and improves the efficiency of the network service layout. SCM is modeled as an integer linear programming problem and resolved via particle swarm optimization. An SCM prototype system is designed based on an SDN controller. Experiments demonstrate that SCM could reduce the network traffic cost and energy consumption efficiently.
[Mh] Termos MeSH primário: Redes de Comunicação de Computadores
Simulação por Computador
Programação Linear
[Mh] Termos MeSH secundário: Algoritmos
Software
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Em] Mês de entrada:1801
[Cu] Atualização por classe:180116
[Lr] Data última revisão:
180116
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171222
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0189336


  7 / 13219 MEDLINE  
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[PMID]:29253852
[Au] Autor:Khan SU; Rahim MKA; Aminu-Baba M; Murad NA
[Ad] Endereço:Advanced RF & Microwave Research Group, Department of Communication Engineering, Faculty of Electrical Engineering, Universiti Teknologi Malaysia, Skudai, Johor, Malaysia.
[Ti] Título:Correction of failure in linear antenna arrays with greedy sparseness constrained optimization technique.
[So] Source:PLoS One;12(12):e0189240, 2017.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:This paper proposes the correction of faulty sensors using a synthesis of the greedy sparse constrained optimization GSCO) technique. The failure of sensors can damage the radiation power pattern in terms of sidelobes and nulls. The synthesis problem can recover the wanted power pattern with reduced number of sensors into the background of greedy algorithm and solved with orthogonal matching pursuit (OMP) technique. Numerical simulation examples of linear arrays are offered to demonstrate the effectiveness of getting the wanted power pattern with a reduced number of antenna sensors which is compared with the available techniques in terms of sidelobes level and number of nulls.
[Mh] Termos MeSH primário: Algoritmos
Redes de Comunicação de Computadores
[Mh] Termos MeSH secundário: Simulação por Computador
Análise Numérica Assistida por Computador
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1801
[Cu] Atualização por classe:180108
[Lr] Data última revisão:
180108
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171219
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0189240


  8 / 13219 MEDLINE  
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[PMID]:29216257
[Au] Autor:Zhao Q; Zhang C; Zhao Z
[Ad] Endereço:Computer Science and Technology College, Jilin University, Changchun, Jilin, China.
[Ti] Título:A decoy chain deployment method based on SDN and NFV against penetration attack.
[So] Source:PLoS One;12(12):e0189095, 2017.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Penetration attacks are one of the most serious network security threats. However, existing network defense technologies do not have the ability to entirely block the penetration behavior of intruders. Therefore, the network needs additional defenses. In this paper, a decoy chain deployment (DCD) method based on SDN+NFV is proposed to address this problem. This method considers about the security status of networks, and deploys decoy chains with the resource constraints. DCD changes the attack surface of the network and makes it difficult for intruders to discern the current state of the network. Simulation experiments and analyses show that DCD can effectively resist penetration attacks by increasing the time cost and complexity of a penetration attack.
[Mh] Termos MeSH primário: Redes de Comunicação de Computadores
Segurança Computacional
[Mh] Termos MeSH secundário: Algoritmos
Simulação por Computador
[Pt] Tipo de publicação:JOURNAL ARTICLE; VALIDATION STUDIES
[Em] Mês de entrada:1712
[Cu] Atualização por classe:171226
[Lr] Data última revisão:
171226
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171208
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0189095


  9 / 13219 MEDLINE  
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[PMID]:28972998
[Au] Autor:Goto H; Takayasu H; Takayasu M
[Ad] Endereço:Department of Computational Intelligence and Systems Science, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, 4259, Nagatsuta-cho, Yokohama 226-8502, Japan.
[Ti] Título:Estimating risk propagation between interacting firms on inter-firm complex network.
[So] Source:PLoS One;12(10):e0185712, 2017.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:We derive a stochastic function of risk propagation empirically from comprehensive data of chain-reaction bankruptcy events in Japan from 2006 to 2015 over 5,000 pairs of firms. The probability is formulated by firm interaction between the pair of firms; it is proportional to the product of α-th power of the size of the first bankrupt firm and ß-th power of that of the chain-reaction bankrupt firm. We confirm that α is positive and ß is negative throughout the observing period, meaning that the probability of cascading failure is higher between a larger first bankrupt firm and smaller trading firm. We additionally introduce a numerical model simulating the whole ecosystem of firms and show that the interaction kernel is a key factor to express complexities of spreading bankruptcy risks on real ecosystems.
[Mh] Termos MeSH primário: Falência
Redes de Comunicação de Computadores
[Mh] Termos MeSH secundário: Japão
Método de Monte Carlo
Risco
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171031
[Lr] Data última revisão:
171031
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171004
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0185712


  10 / 13219 MEDLINE  
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[PMID]:28820890
[Au] Autor:Gul N; Qureshi IM; Omar A; Elahi A; Khan S
[Ad] Endereço:Department of Electrical Engineering, International Islamic University, Islamabad, Pakistan.
[Ti] Título:History based forward and feedback mechanism in cooperative spectrum sensing including malicious users in cognitive radio network.
[So] Source:PLoS One;12(8):e0183387, 2017.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:In cognitive radio communication, spectrum sensing plays a vital role in sensing the existence of the primary user (PU). The sensing performance is badly affected by fading and shadowing in case of single secondary user(SU). To overcome this issue, cooperative spectrum sensing (CSS) is proposed. Although the reliability of the system is improved with cooperation but existence of malicious user (MU) in the CSS deteriorates the performance. In this work, we consider the Kullback-Leibler (KL) divergence method for minimizing spectrum sensing data falsification (SSDF) attack. In the proposed CSS scheme, each SU reports the fusion center(FC) about the availability of PU and also keeps the same evidence in its local database. Based on the KL divergence value, if the FC acknowledges the user as normal, then the user will send unified energy information to the FC based on its current and previous sensed results. This method keeps the probability of detection high and energy optimum, thus providing an improvement in performance of the system. Simulation results show that the proposed KL divergence method has performed better than the existing equal gain combination (EGC), maximum gain combination (MGC) and simple KL divergence schemes in the presence of MUs.
[Mh] Termos MeSH primário: Redes de Comunicação de Computadores
Tecnologia sem Fio
[Mh] Termos MeSH secundário: Cognição
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171013
[Lr] Data última revisão:
171013
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170819
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0183387



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