Periódicos, Publicação

A fuzzy queue-aware routing approach for wireless mesh networks

Recent advances in Wireless Mesh Networks (WMNs) have overcome the drawbacks of traditional wired and ad-hoc networks and now they are seen as a means of allowing last mile communications with quality level assurance in Future Multimedia Systems. However, new routing schemes are needed to provide end-to-end Quality of Service (QoS) and Quality of Experience (QoE) support for delay/loss/jitter-sensitive multimedia applications. The well-known OLSR (Optimized Link State Routing) protocol with ETX (Expected Transmission Count) metric brings many benefits to the path selection process, but has a drawback with regard to queue availability management, which reduces the system performance. This problem is caused when OLSR-EXT control messages are exchanged and the queues of mesh routers along the end-to-end communication path are overloaded. As a result, multimedia-related packets will suffer from loss/delay/jitter and the overall system performance will decrease. This paper proposes the Optimized Link State Routing-Fuzzy ETX Queue (OLSR-FEQ) protocol to overcome the limitations of OLSR-ETX regarding queue availability, QoS and QoE assurance. OLSR-FEQ optimizes network and user-based parameters by coordinating queue availability, QoS and fuzzy issues in the routing decision process as a way of allocating the best paths for multimedia applications. Performance evaluations were carried out with the Network Simulator (NS-2.34) to show the benefits of the proposed solution when compared with existing routing schemes, namely OLSR-ETX, OLSR-FLC, OLSR-MD and HWMP (IEEE 802.11s standard), regarding QoS (unsuccessful packet delivery and throughput) and QoE (PSNR, SSIM, VQM and MOS) parameters.

Periódicos, Publicação

QoE-based packet drop control for 3D-video streaming over wireless networks. QoE-based packet drop control for 3D-video streaming over wireless networks

Currently, the Internet is experiencing a revolution in the provisioning and demand of multimedia services. 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, 3D-video content delivery places increased bandwidth demands, as well as have rigorous Quality of Service (QoS) and Quality of Experience (QoE) requirements for efficient support. This paper proposes a novel QoE-aware packet controller mechanism, which aims at connecting real-time 3D-video streaming applications over congested wireless networks with acceptable levels of QoS and QoE over the time. Simulation experiments were carried out to show the impact and benefit of our proposal. Subjective and objective QoE metrics were used for benchmarking, showing that in congestion periods our solution improves the quality level of real-time 3D-video sequences from the user point-of-view, as well as, optimizes the usage of wireless network resources.

Periódicos, Publicação

A Scheduling Algorithm for Computational Grids that Minimizes Centralized Processing in Genome Assembly of Next-Generation Sequencing Data

Improvements in genome sequencing techniques have resulted in generation of huge volumes of data. As a consequence of this progress, the genome assembly stage demands even more computational power, since the incoming sequence files contain large amounts of data. To speed up the process, it is often necessary to distribute the workload among a group of machines. However, this requires hardware and software solutions specially configured for this purpose. Grid computing try to simplify this process of aggregate resources, but do not always offer the best performance possible due to heterogeneity and decentralized management of its resources. Thus, it is necessary to develop software that takes into account these peculiarities. In order to achieve this purpose, we developed an algorithm aimed to optimize the functionality of de novo assembly software ABySS in order to optimize its operation in grids. We run ABySS with and without the algorithm we developed in the grid simulator SimGrid. Tests showed that our algorithm is viable, flexible, and scalable even on a heterogeneous environment, which improved the genome assembly time in computational grids without changing its quality.

Periódicos, Publicação

Control of QoE based on Algorithms for the Disposal of Packets concerned with Streaming Video in Wireless Networks

Following decades of research, the multimedia networks remain
a great challenge; however, the modern multimedia wireless
networks with video streaming and Internet Protocol voice, have
been attracting special attention due to factors such as mobility
and heterogeneity in the devices that are used, which can
influence the quality of a user’s experience in a particular
application or service. This article compares two algorithms for
the disposal of packets in wireless networks based on the quality
of the experience of the user with video applications when there
is multimedia traffic congestion in the wireless networks and
where the results obtained surpass those of the wireless networks
which lack control of disposal.

Artigos de Conferência, Publicação

Ipsflow–uma proposta de sistema de prevençao de intrusao baseado no framework openflow

The ideal Intrusion Prevention System (IPS) is the one that detects malicious traffic across the network and blocks it at its source. Conventional IPSs do not meet these requirements satisfactorily, because when operating in active mode cannot have a wide coverage on the network and just block the passing traffic. And while catching mirrored traffic, it can only block it when working together with switches from the same solution or vendor. In this scenario, this paper presents IPSFlow, an IPS solution for selective and distributed capture with automated blocking of malicious traffic based on OpenFlow.

Artigos de Conferência, Publicação

A mobile qoe architecture for heterogeneous multimedia wireless networks

One of the main requirements in this emerging wireless multimedia era is the Quality of Experience (QoE) assurance for 2D or 3D video applications in heterogeneous multi-operator environments. Therefore, this paper proposes a QoE Architecture for Heterogeneous Multimedia Wireless Networks, called QoEHand. QoEHand extends the Media Independent Handover (MIH)/IEEE 802.21 proposal with QoEawareness, seamless mobility, dynamic class of service mapping and a set of content adaptation schemes. The proposed solution allows the best connection and considers the QoE needs of mobile clients and available wireless resources in IEEE 802.11e and IEEE 802.16e service classes. Simulation experiments were carried out to show the impact and benefits of QoEHand on the user´s perception, by using objective and subjective QoE metrics.

Artigos de Conferência, Publicação

Real-time QoE prediction for multimedia applications in wireless mesh networks

As Wireless Mesh Networks (WMNs) are being increasingly deployed, there is an increasing demand for new quality assessment mechanisms that allow service operators to evaluate and optimize the utilization of network resources, while ensuring a good quality level on multimedia applications as perceived by end-users. However, existing real-time assessment schemes for WMNs are not capable of capturing the actual quality of received multimedia content with regard to user perception. Therefore, it is not possible to assure the user experience of content services. To address this problem, this paper introduces the Hybrid Quality of Experience (HyQoE) Prediction, which is a quality estimator specially designed to assess realtime multimedia applications. HyQoE is designed based on the framework of the widely used Pseudo-Subjective Quality Assessment (PSQA) Tool which exploits Random Neural Network (RNN). Crucial extension work has been implemented to achieve our objectives. A performance evaluation verifies the effectiveness and advantages of HyQoE in predicting users’ perception of multimedia content in WMNs over existing subjective and hybrid methods.

Artigos de Conferência, Publicação

A proposal management of the legacy network environment using OpenFlow control plane

The Future Internet will arise from the convergence of new network concepts and combine technologies, services, media and content. It will offer flexibility and diversity with scalable content and services that are accessible through a wide range of interfaces and devices. However, the biggest challenge now is how to enable and test the proposed approaches so that they can be validated without sacrificing the current production infrastructure. The OpenFlow protocol allows production networking environments such as campus networks, metropolitan networks or R&D networks, to be used as experimental infrastructure hosting, future Internet architectures, software and protocols, in parallel with the production traffic. During rollout, there is a practical problem that arises with Legacy networks that do not support OpenFlow and need to be replaced/upgraded or refined by means of costly network re-engineering. This paper proposes a new OpenFlow architecture with new components, capable of managing Legacynon-OpenFlow elements by offering a new solution that facilitates the management of Legacy technologies and allows them to be employed in FI experimentation environment and increase the number of experiment with the Legacy Network Environment using OpenFlow control.

Artigos de Conferência, Publicação

Video quality estimator for wireless mesh networks

As Wireless Mesh Networks (WMNs) have been increasingly deployed, where users can share, create and access videos with different characteristics, the need for new quality estimator mechanisms has become important because operators want to control the quality of video delivery and optimize their network resources, while increasing the user satisfaction. However, the development of in-service Quality of Experience (QoE) estimation schemes for Internet videos (e.g., real-time streaming and gaming) with different complexities, motions, Group of Picture (GoP) sizes and contents remains a significant challenge and is crucial for the success of wireless multimedia systems. To address this challenge, we propose a real-time quality estimator approach, HyQoE, for real-time multimedia applications. The performance evaluation in a WMN scenario demonstrates the high accuracy of HyQoE in estimating the Mean Opinion Score (MOS). Moreover, the results highlight the lack of performance of the well-known objective methods and the Pseudo-Subjective Quality Assessment (PSQA) approach.

Artigos de Conferência, Publicação

FHDRA: Uma Proposta para Reduçao da Latência de Handoff Layer-3 em Redes Sem Fio de Multiplos Saltos

Nos últimos anos houve expressivo esforço em prol de soluções de mobilidade para redes sem fio tradicionais, tais como redes de celulares e IEEE 802.11. Outro tipo de rede sem fio que vem se destacando mais recentemente são as redes de múltiplos saltos. Porém a questão da mobilidade neste tipo de rede não é uma simples extensão das redes sem fio tradicionais. Assim, são necessárias soluções específicas de mobilidade que atendam os requisitos dessas novas redes. Visando este objetivo, o presente trabalho propõe uma adaptação ao DHCP, voltado para redes sem fio de múltiplos saltos. A proposta agrega inteligência ao agente DHCP relay, tornando-o capaz de acelerar o processo de configuração de endereço IP aos clientes móveis durante o handoff.

Artigos de Conferência, Publicação

IPSFlow–uma proposta de IPS distribuído para captura e bloqueio seletivo de tráfego malicioso em redes definidas por software

Os tradicionais sistemas de prevenção de intrusão (Intrusion Prevention Systems–IPS) possuem limitações em sua atuação. Quando operam no modo ativo, não possuem uma ampla cobertura na rede, e quando capturam tráfego espelhado, só bloqueiam o tráfego malicioso se atuarem em conjunto com equipamentos de rede do mesmo fabricante ou solução. Neste contexto, propomos neste artigo o IPSFlow, um framework de IPS para Redes Definidas por Software (Software Defined Networks-SDN) que, através do protocolo Openflow, possibilita a criação de um IPS com ampla cobertura na rede, permitindo a captura seletiva e o bloqueio automatizado de tráfego malicioso o mais próximo de sua origem, através da combinação dos resultados de diferentes técnicas de análise de tráfego.

Artigos de Conferência, Publicação

A parametric QoE video quality estimator for Wireless Networks

The development of real-time quality estimator schemes for emerging Internet videos with different content types remains a significant challenge and is crucial for the success of wireless multimedia systems. However, currently in-service assessment schemes fail in capturing subjective aspects of multimedia content related to the user perception. Therefore, this paper proposes an on-the-fly parametric video quality estimator approach (called MultiQoE) for real-time video streaming applications. Experiments in a Wireless Mesh Network (WMN) scenario were carried out to show the accuracy, benefit, and impact of MultiQoE compared to widely used Quality of Experience (QoE) subjective, objective and parametric methods.