Francisco Gortázar

Dr. Francisco Gortázar

orcid

Research Focus & Metrics

Academic Career Length

22Years (2005-Present)

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

Representative Publications

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30 June 2020 in Electronics
Verified
Journal Article
Open access
PDF file
Boni GarcíaBoni García
Boni García
MCMICAEL GALLEGO CARRILLO
MICAEL GALLEGO CARRILLO
FGFrancisco Gortázar
Francisco Gortázar
Mario Munoz-OrganeroMario Munoz-Organero
Mario Munoz-Organero
Selenium is often considered the de-facto standard framework for end-to-end web testing nowadays. It allows practitioners to drive web browsers (such as Chrome, Firefox, Edge, or Opera) in an automated fashion using different language bindings (such as Java, Python, or JavaScript, among others). The term ecosystem, referring to the open-source software domain, includes various components, tools, and other interrelated elements sharing the same technological background. This article presents a descriptive survey aimed to understand how the community uses Selenium and its ecosystem. This survey is structured in seven categories: Selenium foundations, test development, system under test, test infrastructure, other frameworks, community, and personal experience. In light of the current state of Selenium, we analyze future challenges and opportunities around it.

10 March 2020 in Electronics
Verified
Journal Article
Open access
PDF file
Boni GarcíaBoni García
Boni García
FGFrancisco Gortázar
Francisco Gortázar
MCMICAEL GALLEGO CARRILLO
MICAEL GALLEGO CARRILLO
AHAndrew Hines
Andrew Hines
WebRTC is a set of standard technologies that allows exchanging video and audio in real time on the Web. As with other media-related applications, the user-perceived audiovisual quality can be estimated using Quality of Experience (QoE) measurements. This paper analyses the behavior of different objective Full-Reference (FR) models for video and audio in WebRTC applications. FR models calculate the video and audio quality by comparing some original media reference with the degraded signal. To compute these models, we have created an open-source benchmark in which different types of reference media inputs are sent browser to browser while simulating different kinds of network conditions in terms of packet loss and jitter. Our benchmark provides recording capabilities of the impairment WebRTC streams. Then, we use different existing FR metrics for video (VMAF, VIFp, SSIM, MS-SSIM, PSNR, PSNR-HVS, and PSNR-HVS-M) and audio (PESQ, ViSQOL, and POLQA) recordings together with their references. Moreover, we use the same recordings to carry out a subjective analysis in which real users rate the video and audio quality using a Mean Opinion Score (MOS). Finally, we calculate the correlations between the objective and subjective results to find the objective models that better correspond with the subjective outcome, which is considered the ground truth QoE. We find that some of the studied objective models, such as VMAF, VIFp, and POLQA, show a strong correlation with the subjective results in packet loss scenarios.

8 August 2009 in Annals of Operations Research
Verified
Journal Article
Closed access
PDF file
ADAbraham Duarte
Abraham Duarte
RMRafael Martí
Rafael Martí
FGFred Glover
Fred Glover
FGFrancisco Gortázar
Francisco Gortázar

31 July 2019 in Electronics
Verified
Journal Article
Open access
PDF file
Boni GarcíaBoni García
Boni García
LLLuis López-Fernández
Luis López-Fernández
FGFrancisco Gortázar
Francisco Gortázar
MCMICAEL GALLEGO CARRILLO
MICAEL GALLEGO CARRILLO
WebRTC is the umbrella term for several emergent technologies aimed to exchange real-time media in the Web. Like other media-related services, the perceived quality of WebRTC communication can be measured using Quality of Experience (QoE) indicators. QoE assessment methods can be classified as subjective (users’ evaluation scores) or objective (models computed as a function of different parameters). In this paper, we focus on VMAF (Video Multi-method Assessment Fusion), which is an emergent full-reference objective video quality assessment model developed by Netflix. VMAF is typically used to assess video streaming services. This paper evaluates the use of VMAF in a different type of application: WebRTC. To that aim, we present a practical use case built on the top of well-known open source technologies, such as JUnit, Selenium, Docker, and FFmpeg. In addition to VMAF, we also calculate other objective QoE video metrics such as Visual Information Fidelity in the pixel domain (VIFp), Structural Similarity (SSIM), or Peak Signal-to-Noise Ratio (PSNR) applied to a WebRTC communication in different network conditions in terms of packet loss. Finally, we compare these objective results with a subjective evaluation using a Mean Opinion Score (MOS) scale to the same WebRTC streams. As a result, we found a strong correlation of the subjective video quality perceived in WebRTC video calls with the objective results computed with VMAF and VIFp in comparison with SSIM and PSNR and their variants.

1 September 2015 in Knowledge-Based Systems
Verified
Journal Article
Closed access
RCRubén Carrasco
Rubén Carrasco
APAnthanh Pham
Anthanh Pham
MCMICAEL GALLEGO CARRILLO
MICAEL GALLEGO CARRILLO
FGFrancisco Gortázar
Francisco Gortázar
RMRafael Martí
Rafael Martí
ADAbraham Duarte
Abraham Duarte

1 August 2016 in Knowledge-Based Systems
Verified
Journal Article
Closed access
MRManuel Rubio-Sánchez
Manuel Rubio-Sánchez
MCMICAEL GALLEGO CARRILLO
MICAEL GALLEGO CARRILLO
FGFrancisco Gortázar
Francisco Gortázar
ADAbraham Duarte
Abraham Duarte