André Riker

Dr. André Riker

orcid

Research Focus & Metrics

Academic Career Length

16Years (2011-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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6 March 2014 in Wireless Networks
Verified
Journal Article
Open access
PDF file
EAElisangela Aguiar
Elisangela Aguiar
ARAndré Riker
André Riker
Eduardo CerqueiraEduardo Cerqueira
Eduardo Cerqueira
AAAntônio Abelém
Antônio Abelém
MMMu Mu
Mu Mu
Sherali ZeadallySherali Zeadally
Sherali Zeadally
Wireless Mesh Networks (WMNs) are increasingly deployed to enable thousands of users to share, create, and access live video streaming with different characteristics and content, such as video surveillance and football matches. In this context, there is a need for new mechanisms for assessing the quality level of videos because operators are seeking to control their delivery process and optimize their network resources, while increasing the user’s satisfaction. However, the development of in-service and non-intrusive Quality of Experience assessment schemes for real-time Internet videos with different complexity and motion levels, Group of Picture lengths, and characteristics, remains a significant challenge. To address this issue, this article proposes a non-intrusive parametric real-time video quality estimator, called MultiQoE that correlates wireless networks’ impairments, videos’ characteristics, and users’ perception into a predicted Mean Opinion Score. An instance of MultiQoE was implemented in WMNs and performance evaluation results demonstrate the efficiency and accuracy of MultiQoE in predicting the user’s perception of live video streaming services when compared to subjective, objective, and well-known parametric solutions.

1 June 2012
Verified
Conference Paper
Closed access
EAElisangela Aguiar
Elisangela Aguiar
ARAndré Riker
André Riker
AAAntonio Abelem
Antonio Abelem
ECEduardo Cerqueira
Eduardo Cerqueira
MMMu Mu
Mu Mu
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.

18 April 2013 in Wireless Networks
Verified
Journal Article
Closed access
PDF file
Denis RosarioDenis Rosario
Denis Rosario
ECEduardo Cerqueira
Eduardo Cerqueira
ANAugusto Venâncio Neto
Augusto Venâncio Neto
ARAndré Riker
André Riker
RIRoger Immich
Roger Immich
MCMarilia Curado
Marilia Curado

1 June 2020 in Sensors
Verified
Journal Article
Open access
PDF file
SJSidnei Ferreira Junior
Sidnei Ferreira Junior
ARAndré Riker
André Riker
BSBruno Silvestre
Bruno Silvestre
Waldir MoreiraWaldir Moreira
Waldir Moreira
Antonio Oliveira-JrAntonio Oliveira-Jr
Antonio Oliveira-Jr
VBVinicius Borges
Vinicius Borges
Internet of Things (IoT) is evolving to multi-application scenarios in smart cities, which demand specific traffic patterns and requirements. Multi-applications share resources from a single multi-hop wireless networks, where smart devices collaborate to send collected data over a Low-Power and Lossy Networks (LLNs). Routing Protocol for LLNs (RPL) emerged as a routing protocol to be used in IoT scenarios where the devices have limited resources. Instances are RPL mechanisms that play a key role in order to support the IoT scenarios with multiple applications, but it is not standardized yet. Although there are related works proposing multiple instances in RPL on the same IoT network, those works still have limitations to support multiple applications. For instance, there is a lack of flexibility and dynamism in management of multiple instances and service differentiation for applications. In this context, the goal of this work is to develop a solution called DYNAmic multiple RPL instanceS for multiple ioT applicatIons (DYNASTI), which provides more dynamism and flexibility by managing multiple instances of RPL. As a result of this, the traffic performance of multiple applications is enhanced through the routing, taking into consideration the distinct requirements of the applications. In addition, DYNASTI enables the support of sporadic applications as well as the coexistence between regular and sporadic applications. DYNASTI achieved results that demonstrate a significant improvement in reducing the number of control messages, which resulted in increased packet received, decreased end-to-end delay, reduced energy consumption, and an improvement in service differentiation to multiple applications.

1 January 2012
Verified
Conference Paper
Closed access
EAElisangela Aguiar
Elisangela Aguiar
ARAndré Riker
André Riker
MMMu Mu
Mu Mu
SZSherali Zeadally
Sherali Zeadally
ECEduardo Cerqueira
Eduardo Cerqueira
AAAntonio Abelem
Antonio Abelem
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 real-time 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.

1 January 2013
Verified
Conference Paper
Closed access
CQCarlos Quadros
Carlos Quadros
ECEduardo Cerqueira
Eduardo Cerqueira
ANAugusto Venâncio Neto
Augusto Venâncio Neto
APAntonio Pescapé
Antonio Pescapé
ARAndré Riker
André Riker
MCMarilia Curado
Marilia Curado
The convergence of emerging real-time multimedia services, the increasing coverage of wireless networks and the ever-growing popularity of mobile devices, are leading to an era of user-centric multimedia wireless services. In this scenario, heterogeneous communications will co-exist and ensure that the end-user is always best connected. However, the Quality of Experience (QoE) support for emerging video applications in multi-operator environments remains a significant challenge and is crucial for the success of wireless multimedia systems. This paper presents a Quality of Experience Handover Architecture for Converged Heterogeneous Wireless Networks, called QoEHand. QoEHand allows users of multimedia content to be always best connected in IEEE 802.11e and IEEE 802.16e environments. Simulation results show the impact and benefit of the proposed solution in multi-access and multi-operator wireless scenarios by using objective and subjective QoE metrics.