Navegando por Orientadores "CERQUEIRA, Eduardo Coelho"

Agora exibindo 1 - 20 de 20

Acesso aberto (Open Access)
Amazonsocialdtn: IBR-DTN com bluetooth para inclusão digital na Amazônia
(Universidade Federal do Pará, 2015-05-29) FERREIRA, Ronedo de Sá; CERQUEIRA, Eduardo Coelho; http://lattes.cnpq.br/1028151705135221
Despite the evolution in deployed infrastructure and in the way that people access information, still there are those who are socially excluded and have no access to information due to their geographic location (e.g., riverside/countryside communities). This paper proposes an extension to a DTN architecture implementation to allow the dissemination of information in such communities, including educational short-video clips and audio books. The IBR-DTN architecture is complemented with a Bluetooth Convergence Layer, to facilitate the exchange of information over this short-range wireless technology, and with a Bundle Compression mechanism that aims at improving data exchange in short-lived opportunistic contacts happening among nodes. Experiments in a small-scale testbed and in a large-scale simulator environment show that nodes are indeed able to efficiently use contact opportunities to exchange an increased amount of data, allowing people in riverside communities to receive more content related to digital inclusion services.
Acesso aberto (Open Access)
Arcabouço para aprovisionamento de QoS e QoE em redes sem fio heterogêneas WiMAX/Wi-Fi com garantia de equidade entre vazões
(Universidade Federal do Pará, 2011-08-17) VALENTE JUNIOR, Warley Murici; CERQUEIRA, Eduardo Coelho; http://lattes.cnpq.br/1028151705135221
Recently, the society is living amid an agglomerate of mobile devices with multiple wireless interfaces that allow mobile customers home and business solve routine problems in the shortest time and in several locations. On the other hand, the availability of various wireless access technologies such as Wireless Fidelity (Wi-Fi), Worldwide Interoperability for Microwave Access (WiMAX) and Long Term Evolution (LTE), provide a heterogeneous scenario with several connectivity opportunities for the user of devices with multiple interfaces. Some of the current challenges in framing the so called Next Generation Networks (NGN) are the development of frameworks and mechanisms that enable both adequate support for Quality of Service (QoS) and Quality of Experience (QoE) for multimedia applications, and assurance equity among throughputs of different applications in a heterogeneous environment. This dissertation proposes a framework for provisioning of QoS and QoE in heterogeneous wireless networks consisting of WiMAX and Wi-Fi networks. Specifically, our solution provides static mapping of QoS between classes of service WiMAX and access categories Wi-Fi. In addition, our proposal also combines features of equity among throughputs with the mapping solution in order to achieve a good tradeoff for both, for the network operator and for the user, through a new methodology for collection and calculation of aggregate throughput and algorithm for Vertical Handover Decision (VHD). The quantitative evaluation of the proposal was carried out using simulation models in Network Simulator (NS-2). The performance results demonstrate the efficiency of the framework in terms of QoS (throughput, average throughput and delay) and QoE (Peak Signal to Noise Ratio, Structural Similarity Index and Video Quality Metric) metrics.
Acesso aberto (Open Access)
Classification and characterization methods of non-tchnical losses on smart grid scenarios
(Universidade Federal do Pará, 2024-03-28) BASTOS, Lucas de Lima; ROSÁRIO, Denis Lima do; http://lattes.cnpq.br/8273198217435163; https://orcid.org/0000-0003-1119-2450; CERQUEIRA, Eduardo Coelho; ttp://lattes.cnpq.br/1028151705135221
Nowadays, grid resilience as a feature has become non-negotiable, significantly when power interruptions can impact the economy and society. Smart Grids (SGs) widespread popularity enables an immense amount of fine-grained e lectricity consumption data to be collected. However, risks can still exist in the Smart Grid (SG), since SG systems exchange valuable data, the distribution system loses substantial electrical energy. We divide this loss into two categories: technical and non-technical loss. A substantial amount of electrical energy is lost throughout the distribution system, and these losses are divided into two types: technical and non-technical. Non-technical losses (NTL) are any electrical energy consumed that is not invoiced. They may occur due to illegal connections, fraudulent activities, issues with energy meters such as delay in the installation or reading errors, contaminated, defective, or non-adapted measuring equipment, very low valid consumption estimates, faulty connections, and disregarded customers. Non-technical losses are the primary cause of revenue loss in the SG. Annually, electrical utilities incur billions in losses due to non-technical reasons. This thesis presents two detection methods of NTL: classification a nd c haracterization. We c reate a n ensemble predictor-based time series classifier t o c lassify N TL d etection. T his p redictor u ses the user’s energy consumption as a data input for classification, f rom s plitting t he d ata to executing the classifier. A lso, i t a ssumes t he t emporal a spects o f e nergy consumption data during the pre-processing, training, testing, and validation stages. The classification method has the advantage of classifying heterogeneous features in data. The characterization method proposes a study based on Information Theory Quantifiers (ITQ) to mitigate this challenge. First, we use a sliding window to convert the user’s energy consumption time series into a Bandt-Pompe (BP) probability distribution function. Then, we extract the used ITQ. Finally, we apply each metric to the Probability Density Function (PDF) and map the layers to characterize their behavior. The characterization method is advantageous to be used when we have big data. Overall, our best results have been recorded in the fraud detection-based time series classifiers (TSC) model, improving the empirical performance metrics by 10% or more over the other developed models. Our results show that users with normal and abnormal energy consumption can be distinguished using only Information Theory Quantifiers by considering the range of values for each metric.
Acesso aberto (Open Access)
Controle de qualidade de experiência para disseminação de vídeos em tempo real sobre redes ad hoc veiculares
(Universidade Federal do Pará, 2017-03-24) QUADROS, Carlos Jean Ferreira de; SANTOS, Aldri Luis dos; CERQUEIRA, Eduardo Coelho; http://lattes.cnpq.br/1028151705135221
Live video dissemination over Vehicular Ad hoc Networks (VANETs) is fundamental for several services, e.g., roadside video emergency, advertisement's broadcast, and smart video surveillance. All these applications face many challenges due to stringent video quality level requirements, dynamic topologies, and broadcast environments. To deal with these challenges, as well as reduce network routing overhead, geographic Statistical Routing Protocols (SRPs) have been proposed as a suitable solution for the distribution of video flows in VANETs, usually by using positioning and Quality of Service (QoS) parameters. However, rather than only these parameters, a satisfactory video dissemination from the user's perspective also requires video and human-awareness issues. In real situations, due to different requirements and hierarchical structures of multimedia applications, network level and position parameters alone are not enough to select the best relay nodes and build up reliable routes to multi-hop video dissemination with satisfactory reachability and Quality of Experience (QoE) levels. This thesis focuses on improving the disseminated quality of on-road live videos in VANETs. Thus, we propose the cross-layer Broadcast Receiver-based and QoE-driven (BRQ) mechanism, which is modularly coupled to SRPs to offer QoE-aware and video-related parameters for the relay node selection and route maintenance. Thus, nodes decide for themselves to retransmit further the video sequences, enhancing the capacity of the system in delivering videos with better QoE assurance. On top of this, an application-level Error-Control (EC) scheme, namely Interleaving, allows mitigating the effects of frame loss. BRQ was added to a straightforward SRP built using the Distance method, named DBRQ protocol. Results show the gains of DBRQ compared to current SRPs, achieving video dissemination with QoE support, less routing overhead, and satisfactory reachability.
Acesso aberto (Open Access)
Controle de qualidade para 3D-vídeo streaming em redes em malha sem fio
(Universidade Federal do Pará, 2013-02-20) QUADROS, Carlos Jean Ferreira de; CERQUEIRA, Eduardo Coelho; http://lattes.cnpq.br/1028151705135221
Wireless Mesh Networks (WMNs) are envisaged to be one of the most important wireless technologies to provide last mile access in future wireless multimedia networks. In this context, 3D-video is envisioned to attract more and more the multimedia market with the perspective for enhanced applications (video surveillance, mission critical control, entertainment, etc.). However, the challenge of dealing with the uctuating bandwidth, scarce resources and time-varying error rate of these networks, illustrates the need for error-resilient 3D-video transmission. In this context, Forward Error Correction (FEC) approaches are required to provide the distribution of video applications for wireless users with Quality of Service (QoS) and Quality of Experience (QoE) assurance. This study proposal puts forward a FEC-based mechanism with Unequal Error Protection (UEP) to enhance 3D-video transmission in WMNs, while increasing user satisfaction and improving the usage of wireless resources. The benefits and impact of the proposed mechanism will be demonstrated by using simulation, the assessment will be conducted with objective and subjective QoE metrics.
Acesso aberto (Open Access)
Cross-layer optimizations for multimedia distribution over Wireless Multimedia Sensor Networks and Flying Ad-Hoc Networks with quality of experience support
(Universidade Federal do Pará, 2014-07-16) ROSÁRIO, Denis Lima do; BRAUN, Torsten Ingo; http://lattes.cnpq.br/5439824326239585; CERQUEIRA, Eduardo Coelho; http://lattes.cnpq.br/1028151705135221
The proliferation of multimedia content and the demand for new audio or video services have fostered the development of a new era based on multimedia information, which allowed the evolution of Wireless Multimedia Sensor Networks (WMSNs) and also Flying Ad-Hoc Networks (FANETs). In this way, live multimedia services require realtime video transmissions with a low frame loss rate, tolerable end-to-end delay, and jitter to support video dissemination with Quality of Experience (QoE) support. Hence, a key principle in a QoE-aware approach is the transmission of high priority frames (protect them) with a minimum packet loss ratio, as well as network overhead. Moreover, multimedia content must be transmitted from a given source to the destination via intermediate nodes with high reliability in a large scale scenario. The routing service must cope with dynamic topologies caused by node failure or mobility, as well as wireless channel changes, in order to continue to operate despite dynamic topologies during multimedia transmission. Finally, understanding user satisfaction on watching a video sequence is becoming a key requirement for delivery of multimedia content with QoE support. With this goal in mind, solutions involving multimedia transmissions must take into account the video characteristics to improve video quality delivery. The main research contributions of this thesis are driven by the research question how to provide multimedia distribution with high energy-efficiency, reliability, robustness, scalability, and QoE support over wireless ad hoc networks. The thesis addresses several problem domains with contributions on different layers of the communication stack. At the application layer, we introduce a QoE-aware packet redundancy mechanism to reduce the impact of the unreliable and lossy nature of wireless environment to disseminate live multimedia content. At the network layer, we introduce two routing protocols, namely video-aware Multi-hop and multi-path hierarchical routing protocol for Efficient VIdeo transmission for static WMSN scenarios (MEVI), and cross-layer link quality and geographical-aware beaconless OR protocol for multimedia FANET scenarios (XLinGO). Both protocols enable multimedia dissemination with energy-efficiency, reliability and QoE support. This is achieved by combining multiple cross-layer metrics for routing decision in order to establish reliable routes.
Acesso aberto (Open Access)
Entropy-based client selection strategy for federated learning over vehicular network environment
(Universidade Federal do Pará, 2024-08-13) SOUSA, John Lucas Rodrigues Portilho de; ROSÁRIO, Denis Lima do; http://lattes.cnpq.br/8273198217435163; https://orcid.org/0000-0003-1119-2450; CERQUEIRA, Eduardo Coelho; http://lattes.cnpq.br/1028151705135221; https://orcid.org/0000-0003-2162-6523
Federated Learning (FL) emerges as a promising solution to enable collaborative model training for autonomous vehicles while preserving privacy and addressing communication overhead issues. Efficient client selection for participation in the training process remains challenging, especially in scenarios with statistical heterogeneity of data distribution and client failure events. Client failure, an uncontrollable event during training, reduces accuracy, convergence, and speed. This master thesis introduces an entropy-based client selection mechanisms for FL over Vehicular Network environments with client failure and non-IID data distributions. The proposed method is compared to a random selection mechanism in both IID and non-IID scenarios, as well as scenarios with random client drops. The results demonstrate that entropy-based selection outperforms other methods regarding training loss, accuracy, and Area Under the Curve (AUC), particularly in high client dropout and non-IID scenarios. These findings highlight the importance of considering entropy data for client selection to address the challenges posed by client failure and statistical heterogeneity in FL over Vehicular Network.
Acesso aberto (Open Access)
Gerenciamento de mobilidade transparente com suporte integrado a QoS/QoE em redes heterogêneas
(Universidade Federal do Pará, 2012-02-29) SILVA JUNIOR, Reinaldo Boulhosa Ramos da; CERQUEIRA, Eduardo Coelho; http://lattes.cnpq.br/1028151705135221
Advances in wireless communications technology, and the demands for new real-time multimedia applications that meet the Quality of Service (QoS) and Quality of Experience (QoE) requirements, together with the proliferation of mobile equipment, have given rise to new solutions that allow horizontal and vertical mobility in transparent heterogeneous networks. These mobile devices have multiple wireless interfaces where the users are connected so that they can carry out several tasks and services on a daily basis through the technology of different networks that allow a heterogeneous scenario with a wide range of connectivity opportunities for the mobile users. This dissertation sets out a fast decision hierarchical technique for transparent mobility based on cost function in the IEEE 802.21 Standard and class-of-service mapping, to ensure QoS/QoE for the users in periods of mobility called M1H2Q, during which this policy gives information about the best network that can be used for the service employed by the mobile user. It seeks to overcome the problem of having several connections being made by mobile users on the same Wireless Fidelity (wi-fi) network and/or WiMAX (Worldwide Interoperability for Microwave Access) with different services being executed, even though the network is not used correctly. The effects and benefits of the scheme were assessed through NS-2 simulation (Network Simulator- Version 2) and Evalvid, and the QoS and QoE metrics were used to check the results.
Acesso aberto (Open Access)
IPSFlow: Um framework para Sistema de Prevenção de Intrusão baseado em Redes Definidas por Software
(Universidade Federal do Pará, 2013-10-09) NAGAHAMA, Fábio Yu; ABELÉM, Antonio Jorge Gomes; http://lattes.cnpq.br/5376253015721742; CERQUEIRA, Eduardo Coelho; http://lattes.cnpq.br/1028151705135221
Intrusion Detection and Prevention Systems (IDSs/IPSs) are well known tools and well enshrined in the world of information security. However, the lack of integration with network equipment, such as switches and routers, tends to limit the performance of these tools leads to require a proper dimensioning of hardware resources such as processor, memory and high-speed network interfaces used to implement them. Faced with several limitations encountered by researchers and network administrators, the concept of Software Defined Network (SDN), that separates the data and control planes, emerged allowing to adapt the operation of the network according to their needs. Thus, due to standardization and flexibility offered by SDNs, and the limitations presented by IDSs, this dissertation proposes IPSFlow, a framework that uses a network based on the SDN architecture, and the OpenFlow protocol, to create an IPS with wide coverage that blocks a malicious traffic in the equipment closer to the origin. To validate the framework, experiments in the virtual Mininet environment were conducted using Snort as IDS to analyze scanning traffic generated by Nmap from a host to another. The results show that the IPSFlow worked as planned by blocking almost 85% of scanning traffic.
Acesso aberto (Open Access)
Um mecanismo para realçar a conectividade de roteamento geográfico na transmissão multimídia em VANTs
(Universidade Federal do Pará, 2014-06-16) COSTA, Rodrigo Medeiros; CERQUEIRA, Eduardo Coelho; http://lattes.cnpq.br/1028151705135221
Networks of Unmanned Aerial Vehicles (UAVs) have enhanced the use of multimedia applications due to their high degree of mobility and versatility. This increase occurs due the accessibility and use of UAVs quadricopters in several civilian applications. Civilian applications have as main characteristic the use of multimedia data such as videos, because they o er a more detailed visual perspective of the environment. The transmission of such data in UAV networks by geographic protocols improves the rate of data delivery. However, it is not su cient to provide quality of experience (QoE). This is because the high degree of mobility of the quadricopters, which leads to link breaks during multimedia transmission. Consequently, it impairs connectivity and induces high packet losses and delays. Therefore, this paper proposes a mechanism called RCRV, based on techniques for predicting mobility in terms of positioning and link estimation time to enhance the decision making process in geographic routing protocols. Furthermore, it employs criteria that consider the behavior of mobility of UAVs. Thus, RCRV enables the extension of connectivity in UAV networks. The RCRV is a mechanism that complements the strategies of geographic routing protocols. In this way, added the RCRV to the GPSR protocol to evaluate the gains and bene ts of him in a geographic routing protocol. Simulations were performed with di erent speeds and numbers of UAVs. The results showed that the RCRV increases the connectivity in the multimedia transmission, improving the delivery of multimedia content and video quality observed by the user.
Acesso aberto (Open Access)
Mobility and cloud management in wireless heterogeneous 5g networks
(Universidade Federal do Pará, 2020-06-30) PACHECO, Lucas de Sousa; ROSÁRIO, Denis Lima do; http://lattes.cnpq.br/8273198217435163; HTTPS://ORCID.ORG/0000-0003-1119-2450; CERQUEIRA, Eduardo Coelho; http://lattes.cnpq.br/1028151705135221; https://orcid.org/0000-0003-2162-6523
The network mobility management branch is responsible for the protocols and actions taken by the network to ensure connectivity and the continuity of services consumed by mobile users. In this dissertation we analyse how next-generation networks pave the way for the distribution of video in vehicular networks (VANETs), composed by an heterogeneous ultra-dense infrastructure, joining existing wireless communication technologies to obtain greater spectral efficiency. A handover algorithm called HoVe is presented. Based on various criteria for video distribution on ultra-dense 5G VANETs. The simulation results show HoVe’s efficiency in providing videos with 19% higher quality than state-of-the-art algorithms, improving the package delivery rate by at least 30%. This work studies a particular case of VANETs that benefits from computing at the edge of the network, the case of Connected Autonomous Vehicles, or CAVs. Edge and mist computing are emerging solutions for remote data processing for autonomous vehicles, offering greater computational power, as well as the low latency required by autonomous driving. This work proposes the MOSAIC algorithm for service migration and resource management for communication between layers and between layers in edge and fog computing. Simulation results show the efficiency of the proposed algorithm with a better performance of up to 50% in terms of latency and five times less migration failures.
Acesso aberto (Open Access)
A Multi-tier fog architecture for video on demand streaming
(Universidade Federal do Pará, 2018-03-05) SANTOS, Hugo Leonardo Melo dos; CERQUEIRA, Eduardo Coelho; http://lattes.cnpq.br/1028151705135221
Users are changing their traditional communication paradigm based on voice calls or text messages to real-time or on demand video services consumed on mobile devices. In this sense, the transmission of video content considering an adequate Quality of Experience (QoE) in mobile wireless networking infrastructures is a critical issue in both academic and industrial communities. Furthermore, video on demand have a growing consumption over Internet requiring higher bandwidth and lower latency. In this context, a fog computing paradigm can enhance the user experience in wireless networks. Fog computing for video on demand streaming can improve QoE by both video caching and adaptation schemes. However, it is important to evaluate the performance of downloading the videos with diferent codec con_guration and cached closer to the user to measure the gain from the user perspective. We designed a multi-tier fog computing architecture with three levels located in the cloud, nearer the edge and in mobile devices. We evaluated the performance of downloading the video from multiple tier located in distinct geographical with a multimedia application. We assessed in an experimental environment with idle and congested network of streamed videos coded into H.264 and H.265 with three bitrates in a scenario deployed in the FIBRE testbed. We collected QoE metrics, playback start time, freeze times, QoS metric, round-time trip, and energy consumption to analyze the gains for each video configuration. These results showed an important understanding about cache, codec and bitrate schemes in multimedia networking scenarios.
Acesso aberto (Open Access)
Otimização de cobertura, consumo de energia, roteamento e agregação de dados em rede de sensores sem fio utilizando algoritmos genéticos e lógica fuzzy
(Universidade Federal do Pará, 2011-03-04) NUNES, Thiêgo Maciel; MONTEIRO, Dionne Cavalcante; http://lattes.cnpq.br/4423219093583221; CERQUEIRA, Eduardo Coelho; http://lattes.cnpq.br/1028151705135221
The Wireless Sensor Networks (WSN) have limited capacities for processing, storage, communication (bandwidth) and power source, besides having features and basic requirements of a WSN such as: the need for self-organization, communication with diffusion of short-range and multihop routing. This work proposes a tool that optimizes the positioning and the packages delivered through the use of Genetic Algorithm (GA). To resolve the routing problem that improves power consumption and maximize data aggregation is proposed the use of fuzzy logic in the routing protocol Ad hoc Ondemand Distance Vector (AODV). This customization is entitled AODV - Fuzzy for Wireless Sensor Networks (AODV-FWSN). The results show that the proposed solution is efficient and can prolong the life of the WSN and improve the rate of data delivery when compared to similar solutions.
Acesso aberto (Open Access)
Predição de falhas em redes de grades OBS com plano de controle GMPLS
(Universidade Federal do Pará, 2013-01-09) BECHARA, Mariana Castro; CERQUEIRA, Eduardo Coelho; http://lattes.cnpq.br/1028151705135221
This paper presents a proposal for predict failures in OBS grid network with GMPLS to assist applications in collaborative environments, like E-Science. Agents monitoring traffic (DQMA-Fuzzy) for related QoS parameters and others related to imperfections in optical links. A system based on fuzzy logic has been developed to give more robustness and flexibility in decision-making agents, because it presents a solution faster and easily implementable. NS-2 (Network Simulator – 2) simulations show that the proposed DQMA-Fuzzy is able to minimize blockages and balancing the use of grid resources, ensuring well-defined service levels, assisting in traffic engineering and fault prediction.
Acesso aberto (Open Access)
Proposta de arquitetura para o estabelecimento dinâmico de conexões determinísticas e busca de recursos multidomínio em redes grid OBS baseadas no GMPLS
(Universidade Federal do Pará, 2011-06-17) NUNES, Anderson Marques; CERQUEIRA, Eduardo Coelho; http://lattes.cnpq.br/1028151705135221
The processing capacity of research institutions has been growing significantly as processors and workstations increasingly powerful emerging in the market. Considering the improvement of performance in the area computer networks and seeking to fill the demand for ever greater processing, the idea to use networked computers as independent platform for running parallel applications, thus creating the area grid computing. In a network that is under the same administrative domain, is common for there to share resources such as disks, printers, etc. But when the network goes beyond an administrative domain, this sharing becomes very limited. The purpose of computing grids is to allow sharing resources even if they are scattered in different areas administration. This thesis proposes an architecture for dynamic establishment of connections multidomain which makes use of optical burst switching (OBS) using a GMPLS control plane (Generalized Multiprotocol Label Switching). The architecture is based on storing information about grid resources of autonomous systems in a separate component called GOBS Root Server (Grid OBS) and the use of explicit routing to reserve resources along a route that satisfies the performance constraints of an application. The validation of the proposal is made through simulations that show that the architecture is capable of levels of performance differed according to the application class and provides a better utilization of network resources and computing.
Acesso aberto (Open Access)
Proposta de um algoritmo híbrido de agendamento de grants baseado na priorização de filas para gerenciamento de recursos em WDM-PONs
(Universidade Federal do Pará, 2011-04-06) ALEIXO, João Gabriel Evangelista; CERQUEIRA, Eduardo Coelho; http://lattes.cnpq.br/1028151705135221
Passive Optical Networks (PONs) have been experiencing solid growth in the last few decades because were designed as an excellent alternative to solve the major problem for telecommunications networks: the bottleneck in access networks. The next generation of this technology, called Next-Generation PON (NG-PON), is the consequence of developments in optical technologies and provides support to the next generation services, improving TDMPONs performance parameters and expanding the coverage area of these networks. This geographical expansion benefits telecom companies that focus their efforts to simplify the network infrastructure by the unification of metropolitan, access and backhaul networks, decreasing the amount of local exchanges and even the number of nodes and, as a consequence, operational and financial costs. It means significant changes in the access networks scenario that tend to have large distances between ONUs and OLT, and a wide variety of services, making essential the presence of scheduling algorithms that are able to manage all shared resources efficiently, while ensuring fairness and the control in the upstream and downstream traffics dynamic allocation. It is through this context that this dissertation aims to present a hybrid grant scheduling algorithm based on priority queues, which gives efficiency and control to the OLT in the dynamic traffics scheduling. The results presented were obtained by the scenarios developed in a computational simulation environment and were based on the delay and throughput metrics for evaluating the algorithm performance. It will be also evaluated how the amount of resources in the OLT interferes in these metrics.
Acesso aberto (Open Access)
Proposta para minimizar penalidade do tráfego de melhor esforço (BE) em redes óticas passivas ethernet (EPON): análise através de modelo híbrido analítico/simulado
(Universidade Federal do Pará, 2011-05-01) PRADO, Agenor Antonio; CERQUEIRA, Eduardo Coelho; http://lattes.cnpq.br/1028151705135221
An improvement in the scheduling strategy based on weights of classes of traffic (CoS) is proposed in this work so as not to penalize too much the best-effort (BE) class type. As support, a hybrid analytical/simulated model to analyze the performance of upstream flows in Ethernet Optical Passive Networks (EPON) based on frame’s total delay, was developed. The modeling was done using Stochastic Colored Petri Networks (SCPN), from where the average queue size is obtained. Then, this average is used to analytically obtain the total delay. Besides the growth of multimedia real-time applications, the traditional traffic in the Internet (as web browser, email and instant messengers) is still, alone, responsible for 18% of the total traffic (excluding P2P traffic). Adding the P2P applications load, which traffic is also not sensible to delay, a 58% of participation is reached (only P2P traffic was responsible for 40% of the total traffic flowing thru the Internet in the year of 2010). Also in traffic’s forecasts for 2014 the Best Effort (BE) traffic will be still responsible for 40% of the total load in IP networks in the world. This numbers shows that the cares with this kind of traffic cannot be put in low relevance while giving more resources to classes that requires more quality of services. Having the scheduling strategy called IPA(Interleaved Polling with Adapting Cycle Time) as a base, this work demonstrates, by the improvement proposed, that is possible to reach lowers delays in the best effort traffic, without making the upper priority classes reach delays over the parameters recommended for which one.
Acesso aberto (Open Access)
QoE and QoS-aware handover for vídeo transmission in heterogeneous vehicular networks
(Universidade Federal do Pará, 2018-03-19) MEDEIROS, Iago Lins de; CERQUEIRA, Eduardo Coelho; http://lattes.cnpq.br/1028151705135221
Vehicle Ad Hoc Networks (VANETs) offer a wide range of multimedia services ranging from safety and traffic warnings to entertainment and advertising videos. In this context, users can access content through vehicle-to-infrastructure (V2I) communication, which may consider different wireless networks, such as, LTE, Wi-Fi, etc. However, video streaming at a VANET with Quality of Experience (QoE) and Quality of Service (QoS) is a challenging task, due to the high vehicle’s mobility that causes communication failure with the infrastructure. To mitigate such factors, this master’s dissertation presents a handover algorithm that considers QoE, Quality of Service (QoS) and channel quality in heterogeneous networks, known as handover aware of Quality of Service, Experience and Radio (SER). The proposed algorithm considers the Analytic Hierarchy Process (AHP) to adjust the degree of importance of each criteria in choosing the appropriate radio base station that the mobile node must connect to, allowing a more efficient handover decision for video transmission with QoE support. Simulation results show that SER handover delivered videos with QoE 15 % better compared to the algorithms found in the literature.
Acesso aberto (Open Access)
Roteamento multicamada baseado em eficiência energética e qualidade de enlace para redes de sensores sem fio
(Universidade Federal do Pará, 2012-02-28) MACHADO, Kássio Leonardo da Silva; CERQUEIRA, Eduardo Coelho; http://lattes.cnpq.br/1028151705135221
Multilayer routing based on energy efficiency and link quality for wireless sensor networks This Thesis describes the development of a new routing protocol for Wireless Sensor Networks (WSN) for energy restriction and scenarios with high density of nodes. Through the study of the main goals of data communication and the state of the art on the routing protocols and technologies for WSN, this proposal has the following requirements throughput, reliability on data delivery and energy-efficiency. The study presents in detail the AODV (Ad hoc On Demand Distance Vector) protocol and its relevance in the context of WSN, due to the fact of its popularity among the devices. Additionally, it is presented the proposed extensions for AODV and their main drawbacks to provide the required goals. The REL (Routing by Link Energy and Quality) protocol is the result of this research and the proposed solution for on-demand routing protocol for plan architecture based on energy-efficiency and link quality, in order to provide scalability, load balancing and prolong the network lifetime. The REL protocol was evaluated by using simulation and tesbed experiments in order to show its impact and benefits in real and simulated scenarios. The results presents that REL increases the data delivery rate due to the use of reliable links with less probability of error. Additionally, it uses energy issues to select routes, which avoid the fast saturation of nodes and increase the network lifetime.
Acesso aberto (Open Access)
Sistema de identificação duplo (SID) de usuários através dos biosinais fotopletismograma e eletrocardiograma
(Universidade Federal do Pará, 2020-05-28) BASTOS, Lucas de Lima; ROSÁRIO, Denis Lima do; http://lattes.cnpq.br/8273198217435163; CERQUEIRA, Eduardo Coelho; http://lattes.cnpq.br/1028151705135221
With the growth of the area in digital health, wearable devices stood out due to their practicality and comfort in detecting the personal data of their users. In general, these devices have a variety of sensors that capture information about the environment and user, heartbeat, amount of steps, oxygenation in the bloodstream, and photoplethymram, and electrocardiogram. Typically, capturing signals through sensors presents problems that impair signal analysis such as noise, false electromagnetic waves, and unexpected user movements. From this, signal filtering becomes an indispensable step in the process of removing these noises. The sensors can capture these signals, and through later steps, filtering, classification, one can reach in the identification of users. There are traditional methods of recognizing people, such as iris, face, or fingerprints. Today, biosignals are already able to be used for authentication, going through several steps to achieve this goal. Steps such as capture, filtering, extraction of characteristics, classification, and correlation are the main equipment used by these biosignals but still depend on mobile devices. There are many biosignals to be used in the authentication of people. Still, not all are effective; the choice is due to the fact of the shape of the graph of the generated signal, the quality in the capture of signals, and their ability to extract unique characteristics and classification. With these aspects pointed out, this master’s thesis aims to present a Double Identification System of wearable device users through the signs of Photoplethysogram and Electrocardiogram. With this, a method of parameterizing filtering and extracting peaks and the second method of double authentication through the biosignals PPG and ECG. The results indicated a correlation of 80% between the entire raw signal and filtered signal until peak extraction. They obtained an accuracy of 94.1% for the PPG signal without the calculation of errors and 99.98% with the calculation of the error rate, ECG signal reached 88.79% accuracy, for a total of 2809 inferences for each signal for identification of wearable device users.