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Publikacije (79)

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Kamil Koniuch, Sabina Baraković, J. Barakovic, Sruti Subramanian, K. Moor, L. Janowski, Michał Wierzchoń

Modern video streaming services require quality assurance of the presented audiovisual material. Quality assurance mechanisms allow streaming platforms to provide quality levels that are considered sufficient to yield user satisfaction, with the least possible amount of data transferred. A variety of measures and approaches have been developed to control video quality, e.g., by adapting it to network conditions. These include objective matrices of the quality and thresholds identified by means of subjective perceptual judgments. The former group of matrices has recently gained the attention of (multi) media researchers. They call this area of study “Quality of Experience” (QoE). In this paper, we present a theoretical model based on review of previous QoE’s models. We argue that most of them represent the bottom-up approach to modeling. Such models focus on describing as many variables as possible, but with a limited ability to investigate the causal relationship between them; therefore, the applicability of the findings in practice is limited. To advance the field, we therefore propose a structural, top-down model of video QoE that describes causal relationships among variables. This novel top-down model serves as a practical guide for structuring QoE experiments, ensuring the incorporation of influential factors in a confirmatory manner.

Sabina Baraković, Lea Skorin-Kapov, J. Barakovic

Abstract Quality of Experience (QoE) for mobile Web browsing is a complex and multidimensional concept. So far, the research community has addressed the influence of QoE perceptual dimensions on QoE and the impact of various influence factors on QoE perceptual dimensions for mobile Web browsing. In this study, we recognize the gap and need to analyze and gain a deeper understanding of the relationship between multiple influence factors and specific constructs of QoE perceptual dimensions. Utilizing a previously collected dataset, our goal is to fill the research gap in terms of investigating the impact of specific influence factors (loading time, aesthetics, number of taps, information quality) on various constructs comprising the user perception of usability, aesthetics, and information quality in the context of mobile Web browsing. A total of 14 research questions are raised: 7 addressing constructs comprising perceived usability (simplicity, effectiveness, quickness, efficiency, comfort, ease of use, organization), 3 addressing constructs comprising perceived aesthetics (perception of mobile Web site aesthetics, pleasance, clarity, systematicness), and 4 addressing constructs comprising perceived information quality (timeliness, clarity, conciseness, structuralism/completeness/spelling-correctness). Results of posed research questions provide indications on the strength and direction of the impact of considered QoE influence factors on the perception of studied constructs. This study contributes to the research community by being the first to address the impact of chosen QoE influence factors on individual constructs comprising QoE perceptual dimensions in the domain of mobile Web browsing, thus extending the knowledge on interplays and relations in this area. Furthermore, it contributes by revealing numerous new paradigms in the context of usability, aesthetics, and quality of information, such as: (i) beautiful and easy to reach is more simple, effective, efficient, and comfortable, (ii) easy to reach is more pleasant and clear, (iii) informative is more pleasant and clear, (iv) beautifully presented information has higher perceived quality, etc. Reported findings can be utilized by various stakeholders (mobile Web site designers, content providers, device designers, network providers) for indirect management of QoE.

Sabina Baraković, J. Barakovic

Abstract The covid-19 pandemic has motivated the cyber security research activities mainly at national and organizational level, but broader assessment of cyber security at individual level is undoubtedly lacking. Cyber security at individual level refers to humans and their personal cyber security practices that is called cyber hygiene. This study aims to evaluate the impact of the covid-19 pandemic circumstances on cyber hygiene outcomes, i.e., awareness, behavior, and knowledge. The intention was to estimate and compare the cyber hygiene of university students prior to and during the covid-19 pandemic. The results of the survey study indicate that covid-19 pandemic circumstances have caused the change of level of cyber hygiene awareness, behavior, and knowledge of university students. The covid-19 pandemic has improved all these cyber hygiene outcomes and that could be the consequence of intense use of digital space and mirroring of strict covid-19 pandemic protection measures. However, it is evident trend of cyber hygiene knowledge decline which coincides with covid-19 pandemic protection measures relaxation and less utilization of digital services. The findings of this study can be used to improve cyber hygiene worldwide and create a better extraordinary event response as digital space is expected to be increasingly used in future extraordinary circumstances.

J. Husić, Sara Kozić, Sabina Baraković

Abstract This paper aims to provide objective quality metrics assessment for cloud gaming using machine learning algorithms. Three classification algorithms (i.e., Random Forest, Random Three and J-48) have been used for the development of models for objective quality assessment of two metrics: blurriness and blockiness. The results indicate that Random Forest has the best performance in this experimental case of objective quality metrics assessment for cloud gaming. Future research activities will cover comparison of a broad range of objective quality metrics and machine learning algorithms while using larger dataset to enhance the results significance.

Kamil Koniuch, Sabina Baraković, J. Barakovic, K. Moor, L. Janowski, M. Wierzchoń

Modern video streaming services require quality assurance of the presented audiovisual material. Quality assurance mechanisms allow streaming platforms to provide quality levels that are considered sufficient to yield user satisfaction, with the least possible amount of data transferred. A variety of measures and approaches have been developed to control video quality, e.g., by adapting it to network conditions. These include objective matrices of the quality and thresholds identified by means of subjective perceptual judgments. The former group of matrices has recently gained the attention of (multi)media researchers. They call this area of study ``Quality of Experience'' (QoE). In this paper, we present a review of QoE's theoretical models together with a discussion of their properties and implications for the field. We argue that most of them represent the bottom-up approach to modeling. Such models focus on describing as many variables as possible, but with a limited ability to investigate the causal relationship between them; therefore, the applicability of the findings in practice is limited. To advance the field, we therefore propose a structural, top-down model of video QoE that describes causal relationships among variables. We hope that our framework will facilitate designing comparable experiments in the domain.

Quality of experience (QoE) is a multidimensional concept that has been in the focus of the research community for quite some time, especially after the rapid development of information and communication technology (ICT). It has been examined in many contexts (web, telecommunications, economy, medicine, etc.), for different media types (text, audio, video, augmented/virtual reality, etc.) and systems in various domains. Given that logistics and transport is a potent ICT-based domain for research activity in the future, in order to ease and improve the investigation of QoE in the contexts of logistics and transport, we aim to sum the recommendations and lessons learned for the investigation of QoE on the basis of our existing research. These suggestions cover how to treat the concept of QoE and relate it to other fields, techniques and environments to examine and treat QoE, as well as future technologies that need to be included. We provide insight into how these challenges can affect examination of QoE in logistics and transport and discuss ways to overcome them.

Dunja Vučić, Sabina Baraković, Lea Skorin-Kapov

With the widespread use of applications and services supporting audiovisual calls via smartphones, both in business and leisure contexts, a key challenge for service providers is meeting end user Quality of Experience (QoE) expectations and requirements. To successfully meet this challenge, there is a need to identify and analyze the key system-related factors impacting user perceived quality. In this paper, we contribute beyond state-of-the-art by conducting a large scale web-based questionnaire survey to investigate the system-related factors that subjects identify as most influential in contributing to their overall experience and quality perception. We focus in particular on leisure audiovisual calls, established via mobile devices. Our initial survey (Phase 1) was conducted in Feb. 2020, just prior to the outbreak of the COVID-19 pandemic (272 participants). To investigate if the importance of factors has changed due to increased usage of the service caused by the pandemic among the general population, we conducted a second survey (Phase 2) in October 2021 with 249 participants. Based on obtained results, we identify key system-related QoE influence factors belonging to three categories: media quality, functional support, and usability and service design. We observe no significant differences in user opinions and expectations prior to and during the period of increased service usage, despite different participant demographics and study time frames, thus contributing to generalizability of obtained results. Study results contribute to providing insights for designing future user studies investigating QoE, in terms of key factors that should be considered.

Sabina Baraković, J. Barakovic

ABSTRACT Personal data is valuable and vulnerable to individuals who have wrong intentions as any other possessions. This can be mitigated by good cyber hygiene habits. The main aim of this paper is to evaluate, analyze, and understand the level of cyber hygiene knowledge, awareness, and behavioral practices of university students and their mutual relations. We have conducted a survey study containing 30 cyber hygiene questions. Results show that students have acceptable cyber hygiene behavior, but their awareness is not satisfactory, and their knowledge is quite low. Also, the study shows the existence of some relations between gender and current education level and cyber hygiene knowledge, awareness, and behavior, as well as mutual interplay and relations between those cyber hygiene outcomes. The main contributions of this work are bidirectional: theoretical and practical.

Sabina Baraković, J. Barakovic

Abstract The rise of cyber-attacks coming up with the increased use of mobile devices and web services has initiated the growth of interest to understand the impact of Perception of Security (PoS) on Quality of Experience (QoE) in mobile web context and which factors impact PoS. This paper aims to investigate the relations among QoE, PoS, and multiple influence factors in different mobile web contexts. The obtained results have shown that PoS differently impacts QoE in considered mobile web contexts (banking, commerce, browsing, mail, and health). Also, the analyzed factors (risk, reliability and availability, 3rd party seals, privacy, security, grammar quality, aesthetics, reputation, brand name, and usability) have been assigned different weights of influence in terms of PoS in mobile web contexts. These findings open a wide range of potential research that could lead to the increase and improvement of users’ Quality of Life (QoL).

Digital transformation is unstoppable and ongoing process that affects all segments of our everyday lives such as healthcare, banking and finance systems, public administration, or postal and logistics systems. One of the main engines of this process, among many, is the use of cryptocurrencies. Both of these concepts are usually addressed from the firm perspective, but they should be considered from the individual’s perspective as well. Cryptocurrencies recently face increased cyber security threats, thereby affecting the digital transformation and posing additional challenges to it. Therefore, this paper gives a brief overview of security threats and challenges characteristic for cryptocurrency technology today and discusses what can be expected tomorrow. We provide insight how these challenges can affect digital transformation process and propose ways to increase the level of protection for both individuals and organizations.

The fifth generation of mobile telecommunications (5G) is one of the most important novelties of our times due to its influence on the economy and society. The advent of 5G networks and services expands the security threats landscape and requires the implementation of adequate countermeasures. This paper presents a brief overview of 5G security threats and countermeasures from operators’ perspective. The aim is to contribute to the 5G cybersecurity knowledge collection and dissemination by summarizing the key findings and identifying next steps.

P. Marešová, L. Režný, P. Bauer, Oluwaseun Fadeyia, Olaniyi Eniayewu, Sabina Baraković, J. Husić

ABSTRACT Background Deployment of modern assistive technologies is one of the major trends. The main objective is the provisioning of the effectiveness and cost-estimation model for deploying assistive technology solutions in elderly care intended for evaluation and showing specificity to the costs and associated benefits of providing smart technological solutions for seniors. Methods The model uses demographic projections taken from Eurostat for EU countries and the disability incidence from the annual report of the Ministry of Labour and Social Affairs of the Czech Republic as an input. The model was implemented in the software Stella Professional dedicated to system dynamics modelling. Results In relation to the combination of five assistive devices for the elderly the optimal solution the cost savings are 37.8% or182 billion CZK, cumulatively in the simulated time period 2021–2060. The model allows adjustments regarding price levels of various countries through the caregivers’ wage. Obtained results showed robustness of the model to this uncertainty as percentage savings varied only from 37.6% to 39.8%, a mere 2.2% difference. Conclusion With respect to the ongoing demographic transition, the need to employ smart device solutions should further increase and their price could decline. The highest savings will come from countries with higher wages for carers.

Nejla Popaja, Sabina Baraković, J. Husić

Abstract In the process of designing a system, it is necessary to identify potential threats to that system and to include appropriate countermeasures. The process that helps in finding problems in the initial phase of the system design is the threat modeling. Creating a threat model consists of several steps and there are many tools that can help in automating the procedure. This article deals with the threat analysis for an Ambient Assisted Living (AAL) system based on Wireless Sensor Network (WSN), whose main function is to provide information for carers in order to provide the best possible help to the elderly and disabled. We have identified and analysed 99 potential threats to the considered system, where Denial of Service (DoS) resulted in being the most represented class of threats. After conducting the threat assessment, the obtained results showed that the majority of threats are high-risk and justified the use of threat modeling in the design phase, since they can be utilized in further system development stages.

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