RESUMO
Wireless Local Area Networks (WLANs) have revolutionized modern communication by providing a user-friendly and cost-efficient solution for Internet access and network resources. However, the increasing popularity of WLANs has also led to a rise in security threats, including jamming, flooding attacks, unfair radio channel access, user disconnection from access points, and injection attacks, among others. In this paper, we propose a machine learning algorithm to detect Layer 2 threats in WLANs through network traffic analysis. Our approach uses a deep neural network to identify malicious activity patterns. We detail the dataset used, including data preparation steps, such as preprocessing and division. We demonstrate the effectiveness of our solution through series of experiments and show that it outperforms other methods in terms of precision. The proposed algorithm can be successfully applied in Wireless Intrusion Detection Systems (WIDS) to enhance the security of WLANs and protect against potential attacks.
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Algoritmos , Redes Locais , Comunicação , Inundações , AlimentosRESUMO
The article presents a Co-planar Waveguide (CPW) fed antenna of a low-profile, simple geometry, and compact size operating at the dual band for ISM and WLAN applications for 5G communication devices. The antenna has a small size of 30 mm × 18 mm × 0.79 mm and is realized using Rogers RT/Duroid 5880 substrate. The proposed dual-band antenna contains a CPW feedline along with the triangular patch. Later on, various stubs are loaded to obtain optimal results. The proposed antenna offers a dual band at 2.4 and 5.4 GHz while covering the impedance bandwidths of 2.25-2.8 GHz for ISM and 5.45-5.65 GHz for WLAN applications, respectively. The proposed antenna design is studied and analyzed using the Electromagnetic (EM) High-Frequency Structure Simulator (HFSSv9) tool, and a hardware prototype is fabricated to verify the simulated results. As the antenna is intended for on-body applications, therefore, Specific Absorption Rate (SAR) analysis is carried out to investigate the Electromagnetic effects of the antenna on the human body. Moreover, a comparison between the proposed dual-band antenna and other relevant works in the literature is presented. The results and comparison of the proposed work with other literary works validate that the proposed dual-band antenna is suitable for future 5G devices working in Industrial, Scientific, Medical (ISM), and Wireless Local Area Network (WLAN) bands.
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Redes Locais , Tecnologia sem Fio , Humanos , Desenho de Equipamento , ComunicaçãoRESUMO
BACKGROUND: Accumulating evidence have investigated the effects of nighttime light exposure on sleep problems. Nevertheless, the evidence of the relationship between light at night (LAN) and sleep problems remains scarce and inconsistent. OBJECTIVE: Conducted a systematic review and meta-analysis based on observational studies to examine the association between LAN exposure and sleep problems among human subjects. METHODS: We systematically searched three databases (PubMed, Web of Science, and Embase) to identify potentially eligible studies through May 25, 2022. The risk of bias and the quality of the generated evidence were assessed by two authors using the National Toxicology Program's Office of Health Assessment and Translation (OHAT) risk of bias rating tool and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) guideline. Random-effects model was applied to synthesize the risk estimates across eligible studies. The heterogeneity of included studies was quantified by the statistics of I2. RESULTS: A total of 7 cross-sectional studies comprising 577,932 participants were included. Individuals with higher levels of LAN exposure were associated with a 22 % (Summary Odds Ratio, SOR: 1.22, 95 %CI: 1.13-1.33) increased prevalence of sleep problems. The pooled effect size of indoor LAN exposure (SOR: 1.74, 95%CI: 1.27-2.37) associated with sleep problems was significantly higher than outdoor LAN exposure (SOR: 1.19, 95%CI: 1.11-1.29; P = 0.022). Additionally, dose-response analysis demonstrated that LAN intensity threshold exceeding 5.8 nW/cm2/sr (SOR: 1.04, 95%CI: 1.01-1.07) had a significant effect on sleep problems and the prevalence of sleep problems was increasing with increase in LAN intensity. CONCLUSIONS: Overall, our findings support the detrimental effects of LAN exposure on sleep. Maintaining bedroom darkness at night may be a feasible measure to reduce the prevalence of sleep problems. Future longitudinal studies with more advanced LAN assessment methods are required to move the field forward.
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Redes Locais , Transtornos do Sono-Vigília , Humanos , Estudos Transversais , Sono , Escuridão , Luz , Transtornos do Sono-Vigília/epidemiologia , Transtornos do Sono-Vigília/etiologiaRESUMO
Nowadays, the IEEE 802.11 wireless local area network (WLAN) has been widely used for Internet access services around the world. Then, the unfairness or insufficiency in meeting the throughput request can appear among concurrently communicating hosts with the same access point (AP), which should be solved by sacrificing advantageous hosts. Previously, we studied the fairness control method by adopting packet transmission delay at the AP. However, it suffers from slow convergence and may not satisfy different throughput requests among hosts. In this paper, we propose a throughput request satisfaction method for providing fair or different throughput requests when multiple hosts are concurrently communicating with a single AP. To meet the throughput request, the method (1) measures the single and concurrent throughput for each host, (2) calculates the channel occupying time from them, (3) derives the target throughput to achieve the given throughput request, and (4) controls the traffic by applying traffic shaping at the AP. For evaluations, we implemented the proposal in the WLAN testbed system with one Raspberry Pi AP and up to five hosts, and conducted extensive experiments in five scenarios with different throughput requests. The results confirmed the effectiveness of our proposal.
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Redes Locais , Satisfação Pessoal , Tecnologia sem FioRESUMO
An antenna assumes a significant role in expanding the levels of communication to meet the demands of contemporary technologically based industry and private data services. In this paper, a printed compact meander line patch antenna array for wireless local-area network (WLAN) applications in the frequency span of 2.3685-2.4643 GHz is presented. The impedance matching of the antenna is generated by applying a partial rectangular-shaped ground plane backside of the meander line antenna. The proposed antenna evolved on the Rogers RT5880 substrate with a dielectric permittivity of 2.2, and the height of the substrate was 1.575 mm to accomplish the lowest possible return loss. The proposed antenna was developed to achieve particular outcomes, for example, voltage standing wave ratio (VSWR) 1.32, reflection coefficient 20 dB with a bandwidth of 94.2 MHz, a gain of 2.8 dBi, and an efficacy measurement of 97%. This antenna is appropriate for WLAN applications that utilize a 2.4 GHz resonance frequency. The overall dimensions of the antenna are 15 mm × 90.86 mm.
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Redes Locais , Tecnologia sem Fio , Comunicação , Impedância Elétrica , Desenho de EquipamentoRESUMO
Location-based services have permeated Smart academic institutions, enhancing the quality of higher education. Position information of people and objects can predict different potential requirements and provide relevant services to meet those needs. Indoor positioning system (IPS) research has attained robust location-based services in complex indoor structures. Unforeseeable propagation loss in complex indoor environments results in poor localization accuracy of the system. Various IPSs have been developed based on fingerprinting to precisely locate an object even in the presence of indoor artifacts such as multipath and unpredictable radio propagation losses. However, such methods are deleteriously affected by the vulnerability of fingerprint matching frameworks. In this paper, we propose a novel machine learning framework consisting of Bag-of-Features and followed by a k-nearest neighbor classifier to categorize the final features into their respective geographical coordinate data. BoF calculates the vocabulary set using k-mean clustering, where the frequency of the vocabulary in the raw fingerprint data represents the robust final features that improve localization accuracy. Experimental results from simulation-based indoor scenarios and real-time experiments demonstrate that the proposed framework outperforms previously developed models.
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Redes Locais , Aprendizado de Máquina , Tecnologia sem Fio , Algoritmos , Análise por ConglomeradosRESUMO
Wireless networks have drastically influenced our lifestyle, changing our workplaces and society. Among the variety of wireless technology, Wi-Fi surely plays a leading role, especially in local area networks. The spread of mobiles and tablets, and more recently, the advent of Internet of Things, have resulted in a multitude of Wi-Fi-enabled devices continuously sending data to the Internet and between each other. At the same time, Machine Learning has proven to be one of the most effective and versatile tools for the analysis of fast streaming data. This systematic review aims at studying the interaction between these technologies and how it has developed throughout their lifetimes. We used Scopus, Web of Science, and IEEE Xplore databases to retrieve paper abstracts and leveraged a topic modeling technique, namely, BERTopic, to analyze the resulting document corpus. After these steps, we inspected the obtained clusters and computed statistics to characterize and interpret the topics they refer to. Our results include both the applications of Wi-Fi sensing and the variety of Machine Learning algorithms used to tackle them. We also report how the Wi-Fi advances have affected sensing applications and the choice of the most suitable Machine Learning models.
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Redes Locais , Aprendizado de Máquina , Algoritmos , Bases de Dados Factuais , Tecnologia sem FioRESUMO
The present work investigates a novel four-port, multiple-input multiple-output (MIMO), single element dielectric resonator antenna (DRA) for sub-6 GHz band. The DRA is designed and fabricated into a symmetric cross shape and fed using a coplanar waveguide (CPW) feed. A single radiator with four ports is rarely found in the literature. The -10 dB impedance bandwidth covered by the antenna is from 5.52 GHz to 6.2 GHz (11.6%) which covers fifth generation (5G) new radio (NR) bands N47 and wireless local area network (WLAN) IEEE 802.11a band. The isolation between orthogonal ports is about 15 dB while the isolation between opposite ports is 12 dB. The radiation pattern of the proposed antenna is bidirectional due to the absence of a ground plane below the DRA. The orthogonal modes excited in the DRA are [Formula: see text] and [Formula: see text] through the four symmetrical CPW feeds. The simulated and measured results of the proposed design show that MIMO characteristics are achieved by pattern diversity between the ports. Due to the perfect symmetry of the design, the proposed work could be extended to MIMO array applications as well.
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Redes Locais , Tecnologia sem Fio , Dor no Peito , Impedância Elétrica , HumanosRESUMO
The Time-Sensitive Networking (TSN) Task Group has standardised different mechanisms to provide Ethernet with hard real-time guarantees and reliability in layer 2 of the network architecture. Specifically, TSN proposes using space redundancy to increase the reliability of Ethernet networks, but using space redundancy to tolerate temporary faults is not a cost-effective solution. For this reason, we propose to use time redundancy to tolerate temporary faults in the links of TSN-based networks. Specifically, in previous works we proposed the Proactive Transmission of Replicated Frames (PTRF) mechanism to tolerate temporary faults in the links. Now, in this work we present a series of models of TSN and PTRF developed using PRISM, a probabilistic model checker that can be used to evaluate the reliability of systems. After that, we carry out a parametric sensitivity analysis of the reliability achievable by TSN and PTRF and we show that we can increase the reliability of TSN-based networks using PTRF to tolerate temporary faults in the links of TSN networks. This is the first work that presents a quantitative analysis of the reliability of TSN networks.
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Redes Locais , Redes Locais/normas , Reprodutibilidade dos TestesRESUMO
Aiming at the shortcomings of traditional medical device tracking and supervision mode, such as delayed feedback of medical device positioning information, poor visual tracking effect of medical device, and missing early warning of medical device working state supervision, a medical device visual tracking and supervision system based on wireless Local Area Network (LAN) real-time positioning system is developed. Introduction of wireless LAN real-time positioning system, using standard coding algorithm generating device object ID tags, with the only attribute based on RFID read-write terminal complete physical mapping of medical equipment and material ID label, we realize a real-time positioning and traceability of medical equipment, with the help of active warning algorithm based on depth of learning medical equipment working state supervision for early warning, with the help of indoor map generation and trajectory playback medical equipment to realize visualization back regulation. Choose equipment of hospital of Linyi Central Hospital for performance evaluation of the carrier, the evaluation model of engineering practice and clinical statistical analysis, the results show that the system has a complete real-time positioning, visible trace, abnormal warning function. In medical equipment real-time positioning information visual tracing feedback, abnormal state warning etc, medical equipment has obvious advantages.
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Algoritmos , Redes LocaisRESUMO
Although wearable antennas have made great progress in recent years, how to design high-performance antennas suitable for most wireless communication systems has always been the direction of RF workers. In this paper, a new approach for the design and manufacture of a compact, low-profile, broadband, omni-directional and conformal antenna is presented, including the use of a customized flexible dielectric substrate with high permittivity and low loss tangent to realize the compact sensing antenna. Poly-di-methyl-siloxane (PDMS) is doped a certain proportion of aluminum trioxide (Al2O3) and Poly-tetra-fluoro-ethylene (PTFE) to investigate the effect of dielectric constant and loss tangent. Through a large number of comparative experiments, data on different doping ratios show that the new doped materials are flexible enough to increase dielectric constant, reduce loss tangent and significantly improve the load resistance capacity. The antenna is configured with a multisection microstrip stepped impedance resonator structure (SIR) to expand the bandwidth. The measured reflection return loss (S11) showed an operating frequency band from 0.99 to 9.41 GHz, with a band ratio of 146%. The antenna covers two important frequency bands, 1.71-2.484 GHz (personal communication system and wireless body area network (WBAN) systems) and 5.15-5.825 GHz (wireless local area network-WLAN)]. It also passed the SAR test for human safety. Therefore, the proposed antenna offers a good chance for full coverage of WLAN and large-scale development of wearable products. It also has potential applications in communication systems, wireless energy acquisition systems and other wireless systems.
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Dispositivos Eletrônicos Vestíveis , Tecnologia sem Fio , Comunicação , Desenho de Equipamento , Humanos , Redes LocaisRESUMO
A novel wearable button antenna sensor is proposed for the concept of simultaneous wireless information and power transfer (SWIPT). This integrates two working modes for the transfer of power and information, respectively, and optimizes transfer efficiency. An omni-directional radiation pattern is achieved in the 3.5 GHz World Interoperability for Microwave Access (WiMAX) band to support on-body wireless communications, while a circularly polarized broadside radiation pattern is obtained in the 5 GHz wireless local area networks (WLAN) band to harvest power. The measured -10 dB return loss bandwidths are 4.0% (3.47-3.61 GHz) in the lower band, and 25.0% (4.51-5.80 GHz) in the higher band, respectively. An artificial magnetic conductor (AMC) structure with wideband characteristics is applied to obtain a low-profile design and to increase the stability of the antenna sensor. A high radiation efficiency of over 80% in the whole working band is observed. The specific absorption rate (SAR) of the proposed antenna sensor is below 0.509 W/kg at 3.55 GHz, and below 0.0532 W/kg at 5.5 GHz, respectively, which is much lower than the European standard threshold of 2 W/kg. All these characteristics make the designed antenna sensor suitable for on-body information transmission and off-body energy harvesting. The antenna sensor has been prototyped. Simulations and measurements agree well, proving the validity of the new concept.
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Dispositivos Eletrônicos Vestíveis , Tecnologia sem Fio , Desenho de Equipamento , Redes Locais , Micro-OndasRESUMO
A short time after the official launch of WiFi 6, IEEE 802.11 working groups along with the WiFi Alliance are already designing its successor in the wireless local area network (WLAN) ecosystem: WiFi 7. With the IEEE 802.11be amendment as one of its main constituent parts, future WiFi 7 aims to include time-sensitive networking (TSN) capabilities to support low latency and ultra-reliability in license-exempt spectrum bands, enabling many new Internet of Things scenarios. This article first introduces the key features of IEEE 802.11be, which are then used as the basis to discuss how TSN functionalities could be implemented in WiFi 7. Finally, the benefits and requirements of the most representative Internet of Things low-latency use cases for WiFi 7 are reviewed: multimedia, healthcare, industrial, and transport.
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Ecossistema , Tecnologia sem Fio , Atenção à Saúde , Humanos , Redes Locais , Reprodutibilidade dos TestesRESUMO
In recent times, there has been a significant growth in networks known as the wireless body area networks (WBANs). A WBAN connects distributed nodes throughout the human body, which can be placed on the skin, under the skin, or on clothing and can use the human body's electromagnetic waves. An approach to reduce the size of different telecommunication equipment is constantly being sought; this allows these devices to be closer to the body or even glued and embedded within the skin without making the user feel uncomfortable or posing as a danger for the user. These networks promise new medical applications; however, these are always based on the freedom of movement and the comfort they offer. Among the advantages of these networks is that they can significantly increase user's quality of life. For example, a person can carry a WBAN with built-in sensors that calculate the user's heart rate at any given time and send these data over the internet to user's doctor. This study provides a systematic review of WBAN, describing the applications and trends that have been developed with this type of network and, in addition, the protocols and standards that must be considered.
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Equipamentos e Provisões , Monitorização Ambulatorial/instrumentação , Dispositivos Eletrônicos Vestíveis , Biologia Computacional , Redes de Comunicação de Computadores , Equipamentos e Provisões/estatística & dados numéricos , Humanos , Redes Locais , Monitorização Ambulatorial/estatística & dados numéricos , Qualidade de Vida , Dispositivos Eletrônicos Vestíveis/estatística & dados numéricos , Tecnologia sem Fio/estatística & dados numéricosRESUMO
Two-dimensional (2D) layered materials offer intriguing possibilities for novel physics and applications. Before any attempt at exploring the materials space in a systematic fashion, or combining insights from theory, computation, and experiment, a formal description of information about an assembly of arbitrary composition is required. Here, we introduce a domain-generic notation that is used to describe the space of 2D layered materials from monolayers to twisted assemblies of arbitrary composition, existent or not yet fabricated. The notation corresponds to a theoretical materials concept of stepwise assembly of layered structures using a sequence of rotation, vertical stacking, and other operations on individual 2D layers. Its scope is demonstrated with a number of example structures using common single-layer materials as building blocks. This work overall aims to contribute to the systematic codification, capture, and transfer of materials knowledge in the area of 2D layered materials.
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Redes Locais , NanotecnologiaRESUMO
Wireless off-body channel is commonly treated as a traditional communication system assuming large and small scale fading to be independent. In this work, we challenge this approach and experimentally show that in a typical WBAN environment of a single room, this assumption is not accurate. We propose an off-body channel model where path loss and multipath fading are entirely determined by Rician distribution and linked through a stochastic Rician factor K. Treating K as a random variable, whose density is determined by the scenario under consideration, allows our model to naturally address different types of body motion along with correlated shadowing. By means of simulation supported by experiments, we show that our model is able to accurately describe probability densities of instantaneous received power in various static and dynamic settings. In addition, we demonstrate that the proposed approach can predict the off-body diversity gains due to correlated antenna reception when selection combining scheme is applied.
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Redes Locais , Processamento de Sinais Assistido por Computador , Tecnologia sem Fio , Desenho de Equipamento , Humanos , Masculino , Monitorização Fisiológica , Processos EstocásticosRESUMO
Indoor wireless local area network (WLAN) based positioning technologies have boomed recently because of the huge demands of indoor location-based services (ILBS) and the wide deployment of commercial Wi-Fi devices. Channel state information (CSI) extracted from Wi-Fi signals could be calibrated and utilized as a fine-grained positioning feature for indoor fingerprinting localization. One of the main factors that would restrict the positioning accuracy of fingerprinting systems is the spatial resolution of fingerprints (SRF). This paper mainly focuses on the improvement of SRF for indoor CSI-based positioning and a calibrated CSI feature (CCF) with high SRF is established based on the preprocess of both measured amplitude and phase. In addition, a similarity calculation metric for the proposed CCF is designed based on modified dynamic time warping (MDTW). An indoor fingerprinting method based on CCF and MDTW, named CC-DTW, is then proposed to improve the positioning accuracy in indoors. Experiments are conducted in two indoor office testbeds, and the performances of the proposed CC-DTW, one time-reversal (TR) based approach and one Euclidean distance (ED) based approach are evaluated and discussed. The results show that the SRF of CC-DTW outperforms the TR-based one and the ED-based one in both two testbeds in terms of the receiver operating characteristic (ROC) curve metric, and the area under curve (AUC) metric.
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Redes Locais , Algoritmos , Área Sob a Curva , Curva ROC , Tecnologia sem FioRESUMO
The current commercial access point (AP) selection schemes are mostly based on received signal strength, but perform poorly in many situations. To address this problem, a number of alternative schemes collect and analyze the actual load of every candidate AP. However, these schemes may incur significant latency and signaling overhead in dense wireless local area networks (WLANs). To mitigate such overhead, we propose a user application-based AP selection scheme that considers historical information about AP performance. Without inducing any signaling activity, our scheme monitors the amount of network traffic used by applications and estimates the achievable throughput of APs. Our scheme employs the characteristics of application traffic with the intent of accurately predicting AP performance. Using a measurement study in dense WLAN environments, we show that our scheme achieves higher throughput and lower association latency than those of existing schemes in places highly accessible to the user.
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Algoritmos , Redes Locais , Redes de Comunicação de Computadores , Tecnologia sem FioRESUMO
Introducción Los avances tecnológicos alcanzados en relación con las comunicaciones y la información se vieron potenciados luego de la incorporación de la Web 2.00 y el networking impactando las redes y comunidades virtuales. Los dispositivos con tecnología inalámbrica han impactado la eficacia en las comunicaciones, que facilitan el desarrollo de tareas diversas, ventajosas por su repercusión en la economía, imagen y competitividad. El acceso a dispositivos inteligentes se ha extendido en la población ecuatoriana, donde se trabaja por el reconocimiento a los derechos de los pueblos y comunidades indígenas al respeto de sus culturas, tradiciones, costumbres, valores, saberes y formas de vida, siendo Otavalo una de las ciudades de mayor presencia indígena del país. Objetivo Exponer cómo incorporar la tecnología en lo cotidiano con fines sociales, así como también potenciar el desarrollo y los emprendimientos locales. Metodología A partir de entrevistar al Coordinador Cantonal de las comunidades indígenas otavaleñas, interesado en divulgar e impulsar el desarrollo local, se le explica de las facilidades que brinda la herramienta de la Red Local inalámbrica Kimera, que utiliza software libre y contenido abierto. Luego de un intercambio con la comunidad de Gualsaqui se obtiene el consentimiento y se completa la información de su interés a divulgarse. Conclusiones Se conforma una red local inalámbrica que constituye una propuesta para la divulgación de la historia, sistema legal y datos de la comunidad, información que es de fácil actualización por no exigir de conocimientos técnicos específicos para su personalización(AU)
Introduction Technological progress in relation to communications and information were boosted after incorporating Web 2.00 and networking impacting networks and virtual communities. Devices with wireless technology have impacted the effectiveness of communications, which facilitate the development of diverse tasks, advantageous for their impact on the economy, image and competitiveness. Access to smart devices has spread throughout the Ecuadorian population, where work is being done to recognize the rights of indigenous peoples and communities to respect their cultures, traditions, customs, values, knowledge and ways of life, Otavalo being one of the the cities with the greatest indigenous presence in the country. Objective To show how to incorporate technology in daily life with social purposes, as well as to promote development and local enterprises. Methodology After interviewing the Cantonal Coordinator of the Otavalo indigenous communities, interested in spreading and promoting local development, he is explained about the facilities offered by the Kimera Wireless Local Network tool, which uses free software and open content. After an exchange with the community of Gualsaqui, consent is obtained and the information of interest to be disseminated is complemented. Conclusions A wireless local network is installed that constitutes a proposal for the disclosure of the history, legal system and community data, information that is easy to update because it does not require specific technical knowledge for its customization(AU)