User experience and robustness in social virtual reality applications

Cloud-based applications that rely on emerging technologies such as social virtual reality are increasingly being deployed at high-scale in e.g., remote-learning, public safety, and healthcare. These applications increasingly need mechanisms to maintain robustness and immersive user experience as a joint consideration to minimize disruption in service availability due to cyber attacks/faults. Specifically, effective modeling and real-time adaptation approaches need to be investigated to ensure that the application functionality is resilient and does not induce undesired cybersickness levels. In this thesis, we investigate a novel ‘DevSecOps' paradigm to jointly tune both the robustness and immersive performance factors in social virtual reality application design/operations. We characterize robustness factors considering Security, Privacy and Safety (SPS), and immersive performance factors considering Quality of Application, Quality of Service, and Quality of Experience (3Q). We achieve “harmonized security and performance by design” via modeling the SPS and 3Q factors in cloud-hosted applications using attack-fault trees (AFT) and an accurate quantitative analysis via formal verification techniques i.e., statistical model checking (SMC). We develop a real-time adaptive control capability to manage SPS/3Q issues affecting a critical anomaly event that induces undesired cybersickness. This control capability features a novel dynamic rule-based approach for closed-loop decision making augmented by a knowledge base for the SPS/3Q issues of individual and/or combination events. Correspondingly, we collect threat intelligence on application and network based cyber-attacks that disrupt immersiveness, and develop a multi-label K-NN classifier as well as statistical analysis techniques for critical anomaly event detection. We validate the effectiveness of our solution approach in a real-time cloud testbed featuring vSocial, a social virtual reality based learning environment that supports delivery of Social Competence Intervention (SCI) curriculum for youth. Based on our experiment findings, we show that our solution approach enables: (i) identification of the most vulnerable components that impact user immersive experience to formally conduct risk assessment, (ii) dynamic decision making for controlling SPS/3Q issues inducing undesirable cybersickness levels via quantitative metrics of user feedback and effective anomaly detection, and (iii) rule-based policies following the NIST SP 800-160 principles and cloud-hosting recommendations for a more secure, privacy-preserving, and robust cloud-based application configuration with satisfactory immersive user experience.Includes bibliographical references (pages 133-146)

VirtFogSim: A parallel toolbox for dynamic energy-delay performance testing and optimization of 5G Mobile-Fog-Cloud virtualized platforms

It is expected that the pervasive deployment of multi-tier 5G-supported Mobile-Fog-Cloudtechnological computing platforms will constitute an effective means to support the real-time execution of future Internet applications by resource- and energy-limited mobile devices. Increasing interest in this emerging networking-computing technology demands the optimization and performance evaluation of several parts of the underlying infrastructures. However, field trials are challenging due to their operational costs, and in every case, the obtained results could be difficult to repeat and customize. These emergingMobile-Fog-Cloud ecosystems still lack, indeed, customizable software tools for the performance simulation of their computing-networking building blocks. Motivated by these considerations, in this contribution, we present VirtFogSim. It is aMATLAB-supported software toolbox that allows the dynamic joint optimization and tracking of the energy and delay performance of Mobile-Fog-Cloud systems for the execution of applications described by general Directed Application Graphs (DAGs). In a nutshell, the main peculiar features of the proposed VirtFogSim toolbox are that: (i) it allows the joint dynamic energy-aware optimization of the placement of the application tasks and the allocation of the needed computing-networking resources under hard constraints on acceptable overall execution times, (ii) it allows the repeatable and customizable simulation of the resulting energy-delay performance of the overall system; (iii) it allows the dynamic tracking of the performed resource allocation under time-varying operational environments, as those typically featuring mobile applications; (iv) it is equipped with a user-friendly Graphic User Interface (GUI) that supports a number of graphic formats for data rendering, and (v) itsMATLAB code is optimized for running atop multi-core parallel execution platforms. To check both the actual optimization and scalability capabilities of the VirtFogSim toolbox, a number of experimental setups featuring different use cases and operational environments are simulated, and their performances are compared

Edge-based Runtime Verification for the Internet of Things

Complex distributed systems such as the ones induced by Internet of Things (IoT) deployments, are expected to operate in compliance to their requirements. This can be checked by inspecting events flowing throughout the system, typically originating from end-devices and reflecting arbitrary actions, changes in state or sensing. Such events typically reflect the behavior of the overall IoT system – they may indicate executions which satisfy or violate its requirements. This article presents a service-based software architecture and technical framework supporting runtime verification for widely deployed, volatile IoT systems. At the lowest level, systems we consider are comprised of resource-constrained devices connected over wide area networks generating events. In our approach, monitors are deployed on edge components, receiving events originating from end-devices or other edge nodes. Temporal logic properties expressing desired requirements are then evaluated on each edge monitor in a runtime fashion. The system exhibits decentralization since evaluation occurs locally on edge nodes, and verdicts possibly affecting satisfaction of properties on other edge nodes are propagated accordingly. This reduces dependence on cloud infrastructures for IoT data collection and centralized processing. We illustrate how specification and runtime verification can be achieved in practice on a characteristic case study of smart parking. Finally, we demonstrate the feasibility of our design over a testbed instantiation, whereupon we evaluate performance and capacity limits of different hardware classes under monitoring workloads of varying intensity using state-of-the-art LPWAN technology

Latency Thresholds for Usability in Games: A Survey

User interactions in interactive applications are time critical operations;late response will degrade the experience. Sensitivity to delay doeshowever vary greatly with between games. This paper surveys existingliterature on the specifics of this limitation. We find a classificationwhere games are grouped with others of roughly the same requirements.In addition we find some numbers on how long latency is acceptable.These numbers are however inconsistent between studies, indicatinginconsistent methodology or insufficient classification of games andinteractions. To improve classification, we suggest some changes.In general, research is too sparse to draw any strong or statisticallysignificant conclusions. In some of the most time critical games, latencyseems to degrade the experience at about 50 ms

Cyber deception against DDoS attack using moving target defence framework in SDN IOT-EDGE networks

Software Defined Networking (SDN) networking paradigm advancements are advantageous, but they have also brought new security concerns. The Internet of Things (IoT) Edge Computing servers provide closer access to cloud services and is also a point of target for availability attacks. The Distributed Denial of Service (DDoS) attacks on SDN IoT-Edge Computing caused by botnet of IoT hosts has compromised major services and is still an impending concern due to the Work From Home virtual office shift attributed by Covid19 pandemic. The effectiveness of a Moving Target Defense (MTD) technique based on SDN for combating DDoS attacks in IoT-Edge networks was investigated in this study with a test scenario based on a smart building. An MTD Reactive and Proactive Network Address Shuffling Mechanism was developed, tested, and evaluated with results showing successful defence against UDP, TCP SYN, and LAND DDoS attacks; preventing IoT devices from being botnet compromised due to the short-lived network address; and ensuring reliable system performance

Network streaming and compression for mixed reality tele-immersion

Bulterman, D.C.A. [Promotor]Cesar, P.S. [Copromotor

Large-Scale Measurement of Real-Time Communication on the Web

Web Real-Time Communication (WebRTC) is getting wide adoptions across the browsers (Chrome, Firefox, Opera, etc.) and platforms (PC, Android, iOS). It enables application developers to add real-time communications features (text chat, audio/video calls) to web applications using W3C standard JavaScript APIs, and the end users can enjoy real-time multimedia communication experience from the browser without the complication of installing special applications or browser plug-ins. As WebRTC based applications are getting deployed on the Internet by thousands of companies across the globe, it is very important to understand the quality of the real-time communication services provided by these applications. Important performance metrics to be considered include: whether the communication session was properly setup, what are the network delays, packet loss rate, throughput, etc. At Callstats.io, we provide a solution to address the above concerns. By integrating an JavaScript API into WebRTC applications, Callstats.io helps application providers to measure the Quality of Experience (QoE) related metrics on the end user side. This thesis illustrates how this WebRTC performance measurement system is designed and built and we show some statistics derived from the collected data to give some insight into the performance of today’s WebRTC based real-time communication services. According to our measurement, real-time communication over the Internet are generally performing well in terms of latency and loss. The throughput are good for about 30% of the communication sessions