Relaterade till projektet

A Blockchain-based Approach for Assessing Compliance with SLA-guaranteed IoT Services

2020 IEEE International Conference on Smart Internet of Things (SmartIoT), Beijing, China, 2020, pp. 213-220, doi: 10.1109/SmartIoT49966.2020.00039.

A. Alzubaidi, K. Mitra, P. Patel and E. Solaiman

Big data processing systems, such as Hadoop and Spark, usually work on large-scale, highly-concurrent, and multi-tenant environments that can easily cause hardware and software malfunctions or failures, thereby leading to performance degradation. Several systems and methods exist to detect big data processing systems’ performance degradation, perform root-cause analysis, and even overcome the issues causing such degradation. However, these solutions focus on specific problems such as straggler and inefficient resource utilization. There is a lack of a generic and extensible framework to support the real-time diagnosis of big data systems. In this paper, we propose, develop and validate AutoDiagn. This generic and flexible framework provides holistic monitoring of a big data system while detecting performance degradation and enabling root-cause analysis. We present the implementation and evaluation of AutoDiagn that interacts with a Hadoop cluster deployed on a public cloud and tested with real-world benchmark applications. Experimental results show that AutoDiagn has a small resource footprint, high throughput and low latency.

Experiences and Challenges of Providing IoT-Based Care for Elderly in Real-Life Smart Home Environments.

Scalable Computing and Communications. Springer, Cham. (2020)

Saguna S., Åhlund C., Larsson A

Elderly population across the world is on the rise and municipalities along with caregivers are struggling to provide care due to limited resources. Sweden’s elderly population is set to grow significantly by 2050 where the number of people between 65–79 years and 80 years and over is expected to increase by 45% and 87% respectively [1]. The same trend continues within Europe where 25% of the population will be over 65 years of age by the year 2020, and the age group of 65–80 years is predicted to rise by 40% from the year 2010 to 2030 [2]. The rise in elderly population has increased the stress on municipalities and caregivers; and has created the need for new healthcare solutions that are feasible, affordable and easily accessible to all. Smart homes equipped with sensors have already made life easier for those living in them for many decades now by providing home automation solutions. We are also witnessing an increase in the use of Information Communication Technologies (ICT) to assist elderly population and decrease in operational costs. ICT systems in assisting elderly population have an immense potential for providing in-home care to the elderly [3]. The advent of the Internet of Things (IoT) with low-cost and prolific sensors has furthered this trend of home automation and monitoring solutions being used for elderly healthcare [4, 5]. Alongside, the field of ambient assisted homes has continuously paved the way for providing an improved quality of life for those in need such as patients with dementia or chronic conditions as well as elderly living alone at home [5–7].

Context-Aware IoT-Enabled Cyber-Physical Systems: A Vision and Future Directions.

Springer, Cham. (2020)

Mitra K., Ranjan R., Åhlund C

The next-generation cyber-physical systems (CPSs) will not only be limited to industries but will span across multiple application-areas regarding smart cities and regions. These CPSs will leverage the recent advancements in the areas of cloud computing, Internet of Things and big data to provision citizen-centric applications and services such as smart hybrid energy grids, smart waste management, smart healthcare and smart transportation. Challenges regarding context-awareness, quality of service and quality of experience, mobility management, middleware platforms, service level agreements, trust, and privacy needs to be solved to realize such CPSs. This chapter discusses these challenges in detail and proposes ICICLE – a context-aware IoT-enabled cyber-physical system as a blueprint for next-generation CPSs.

Handbook of Integration of Cloud Computing, Cyber Physical Systems and Internet of Things.

Scalable Computing and Communications. Springer, Cham

Ranjan R., Mitra K., Prakash Jayaraman P., Wang L., Zomaya A.Y. (eds)

This handbook covers recent advances in the integration of three areas, namely, cloud computing, cyber-physical systems, and the Internet of things which is expected to have a tremendous impact on our daily lives. It contains a total of thirteen peer-reviewed and edited chapters. This book covers topics such as context-aware cyber-physical systems, sustainable cloud computing, fog computing, and cloud monitoring; both the theoretical and practical aspects belonging to these topics are discussed. All the chapters also discuss open research challenges in the areas mentioned above. Finally, the handbook presents three use cases regarding healthcare, smart buildings and disaster management to assist the audience in understanding how to develop next-generation IoT- and cloud-enabled cyber-physical systems. This timely handbook is edited for students, researchers, as well as professionals who are interested in the rapidly growing fields of cloud computing, cyber-physical systems, and the Internet of things.

Performance Evaluation of FIWARE: A Cloud-Based IoT Platform for Smart Cities

Journal of Parallel and Distributed Computing Systems, Elsevier, 2019

Victor Araujo, Karan Mitra,  Saguna Saguna, Christer Åhlund

As the Internet of Things (IoT) becomes a reality, millions of devices will be connected to IoT platforms in smart cities. These devices will cater to several areas within a smart city such as healthcare, logistics, and transportation. These devices are expected to generate significant amounts of data requests at high data rates, therefore, necessitating the performance benchmarking of IoT platforms to ascertain whether they can efficiently handle such devices. In this article, we present our results gathered from extensive performance evaluation of the cloud-based IoT platform, FIWARE. In particular, to study FIWARE’s performance, we developed a testbed and generated CoAP and MQTT data to emulate large-scale IoT deployments, crucial for future smart cities. We performed extensive tests and studied FIWARE’s performance regarding vertical and horizontal scalability. We present bottlenecks and limitations regarding FIWARE components and their cloud deployment. Finally, we discuss cost-efficient FIWARE deployment strategies that can be extremely beneficial to stakeholders aiming to deploy FIWARE as an IoT platform for smart cities.

Propagation Model Evaluation for LoRaWAN: Planning Tool Versus Real Case Scenario

Proceedings of  The IEEE 5th World Forum on Internet of Things (WF-IoT) 2019, Limerick Ireland

Nibia Souza Bezerra, Christer Åhlund, Saguna Saguna, Vicente A. de Sousa Jr


LoRa has emerged as a prominent technology for the Internet of Things (IoT), with LoRa Wide Area Network (LoRaWAN) emerging as a suitable connection solution for smart things. The choice of the best location for the installation of gateways, as well as a robust network server configuration, are key to the deployment of a LoRaWAN. In this paper, we present an evaluation of Received Signal Strength Indication (RSSI) values collected from the real-life LoRaWAN deployed in Skelleftea, Sweden, when compared with the values calculated by a Radio Frequency (RF) planning tool for the Irregular Terrain Model (ITM), Irregular Terrain with Obstructions Model (ITWOM) and Okumura-Hata propagation models. Five sensors are configured and deployed along a wooden bridge, with different Spreading Factors (SFs), such as SF 7, 10 and 12. Our results show that the RSSI values calculated using the RF planning tool for ITWOM are closest to the values obtained from the real-life LoRaWAN. Moreover, we also show evidence that the choice of a propagation model in an RF planning tool has to be made with care, mainly due to the terrain conditions of the area where the network and the sensors are deployed.

Performance Evaluation of Scalable and Distributed IoT Platforms for Smart Regions

Masters Thesis, Luleå University of Technology, Sweden, 2017

Victor Araujo


As the vision of the Internet of Things (IoT) becomes a reality, thousands of devices will be connected to IoT platforms in smart cities and regions. These devices will actively send data updatestocloud-basedplatforms,aspartofsmartapplicationsindomainslikehealthcare,traffic and pollution monitoring. Therefore, it is important to study the ability of modern IoT systems to handle high rates of data updates coming from devices. In this work we evaluated the performance of components of the Internet of Things Services Enablement Architecture of the European initiative FIWARE. We developed a testbed that is able to inject data updates using MQTT and the CoAP-based Lightweight M2M protocols, simulating large scale IoT deployments. Our extensive tests considered the vertical and horizontal scalability of the components oftheplatform. Ourresultsfoundthelimitsofthecomponentswhenhandlingtheload, andthe scaling strategies that should be targeted by implementers. We found that vertical scaling is not an effective strategy in comparison to the gains achieved by horizontally scaling the database layer. We reflect about the load testing methodology for IoT systems, the scalability needs of different layers and conclude with future challenges in this topic.

Analysis and Estimation of Video QoE in Wireless Cellular Networks using Machine Learning

Proceedings of the  11th International Conference on Quality of Multimedia Experience (QoMEX), Berlin, Germany, 2019

Dimitar Minovski, Christer Åhlund, Karan Mitra, Per Johansson


The use of video streaming services are increasing in the cellular networks, inferring a need to monitor video quality to meet users’ Quality of Experience (QoE). The so-called no-reference (NR) models for estimating video quality metrics mainly rely on packet-header and bitstream information. However, there are situations where the availability of such information is limited due to tighten security and encryption, which necessitates exploration of alternative parameters for conducting video QoE assessment. In this study we collect real-live in-smartphone measurements describing the radio link of the LTE connection while streaming reference videos in uplink. The radio measurements include metrics such as RSSI, RSRP, RSRQ, and CINR. We then use these radio metrics to train a Random Forrest machine learning model against calculated video quality metrics from the reference videos. The aim is to estimate the Mean Opinion Score (MOS), PSNR, Frame delay, Frame skips, and Blurriness. Our result show 94% classification accuracy, and 85% model accuracy (R 2 value) when predicting the MOS using regression. Correspondingly, we achieve 89%, 84%, 85%, and 82% classification accuracy when predicting PSNR, Frame delay, Frame Skips, and Blurriness respectively. Further, we achieve 81%, 77%, 79%, and 75% model accuracy (R 2 value) regarding the same parameters using regression

ALPINE: A Bayesian System for Cloud Performance Diagnosis and Prediction

The 14th IEEE International Conference on Services Computing (IEEE SCC 2017), Honolulu, Hawaii

Karan Mitra, Saguna Saguna, Christer Ahlund, Rajiv Ranjan


Cloud performance diagnosis and prediction is a challenging problem due to the stochastic nature of the cloud systems. Cloud performance is affected by a large set of factors including (but not limited to) virtual machine types, regions, workloads, wide area network delay and bandwidth. Therefore, necessitating the determination of complex relationships between these factors. The current research in this area does not address the challenge of building models that capture the uncertain and complex relationships between these factors. Further, the challenge of cloud performance prediction under uncertainty has not garnered sufficient attention. This paper proposes develops and validates ALPINE, a Bayesian system for cloud performance diagnosis and prediction. ALPINE incorporates Bayesian networks to model uncertain and complex relationships between several factors mentioned above. It handles missing, scarce and sparse data to diagnose and predict stochastic cloud performance efficiently. We validate our proposed system using extensive real data and trace-driven analysis and show that it predicts cloud performance with high accuracy of 91.93%.

A Bayesian System for Cloud Performance Diagnosis and Prediction

Proceedings of the 8th IEEE International Conference on Cloud Computing Technology and Science (IEEE CloudCom 2016), Luxembourg

Emanuel Palm, Karan Mitra, Saguna Saguna, Christer Åhlund


The  stochastic  nature  of  the  cloud  systems  makes
cloud  quality  of  service  (QoS)  performance  diagnosis  and  pre-
diction a challenging task. A plethora of factors including virtual
machine   types,   data   centre   regions,   CPU   types,   time-of-the-
day,  and  day-of-the-week  contribute  to  the  variability  of  the
cloud  QoS.  The  state-of-the-art  methods  for  cloud  performance
diagnosis  do  not  capture  and  model  complex  and  uncertain
inter-dependencies between these factors for efficient cloud QoS
diagnosis and prediction. This paper presents ALPINE, a proof-
of-concept  system  based  on  Bayesian  Networks.  Using  a  real-
life  dataset,  we  demonstrate  that  ALPINE  can  be  utilised  for
efficient  cloud  QoS  diagnosis  and  prediction  under  stochastic
cloud  conditions.

Anomaly Detection using Machine Learning to Discover Sensor Tampering in IoT Systems

Aditya Kumar Pathak, Saguna Saguna, Karan Mitra, Christer Åhlund


With the rapid growth of the Internet of Things (IoT) applications in smart regions/cities, for example, smart healthcare, smart homes/offices, there is an increase in security threats and risks. The IoT devices solve real-world problems by providing real-time connections, data and information. Besides this, the attackers can tamper with sensors, add or remove them physically or remotely. In this study, we address the IoT security sensor tampering issue in an office environment. We collect data from real-life settings and apply machine learning to detect sensor tampering using two methods. First, a real-time view of the traffic patterns is considered to train our isolation forest-based unsupervised machine learning method for anomaly detection. Second, based on traffic patterns, labels are created, and the decision tree supervised method is used, within our novel Anomaly Detection using Machine Learning (AD-ML) system. The accuracy of the two proposed models is presented. We found 84% with silhouette metric accuracy of isolation forest. Moreover, the result based on 10 cross-validations for decision trees on the supervised machine learning model returned the highest classification accuracy of 91.62% with the lowest false positive rate.

Augmented Reality-Assisted Healthcare System for Caregivers in Smart Regions. (Winner: Best paper award).

2021 IEEE International Smart Cities Conference (ISC2)

J.C. Kim, S. Saguna, C. Åhlund and K. Mitra


The rise in the aging population worldwide is already negatively impacting healthcare systems due to the lack of resources. It is envisioned that the development of novel Internet of Things (IoT)-enabled smart city healthcare systems may not only alleviate the stress on the current healthcare systems but may significantly improve the overall quality of life of the elderly. As more elderly homes are fitted with IoT, and intelligent healthcare becomes the norm, there is a need to develop innovative augmented reality (AR) based applications and services that make it easier for caregivers to interact with such systems and assist the elderly on a daily basis. This paper proposes, develops, and validates an AR and IoT-enabled healthcare system to be used by caregivers. The proposed system is based on a smart city IoT middleware platform and provides a standardized, intuitive and non-intrusive way to deliver elderly person’s information to caregivers. We present our prototype, and our experimental results show the efficiency of our system in IoT object detection and relevant information retrieval tasks. The average execution time, including object detection, communicating with a server, and rendering the results in the application, takes on average between 767ms and 1,283ms.

An Automated Real-time Diagnosis Framework for Big Data Systems

Demirbaga U, Wen Z, Noor A, Mitra K, Alwasel K, Garg S, Zomaya A, Ranjan R.


Big data processing systems, such as Hadoop and Spark, usually work in large-scale, highly-concurrent, and multi-tenant environments that can easily cause hardware and software malfunctions or failures, thereby leading to performance degradation. Several systems and methods exist to detect big data processing systems’ performance degradation, perform root-cause analysis, and even overcome the issues causing such degradation. However, these solutions focus on specific problems such as stragglers and inefficient resource utilization. There is a lack of a generic and extensible framework to support the real-time diagnosis of big data systems. In this article, we propose, develop and validate AutoDiagn. This generic and flexible framework provides holistic monitoring of a big data system while detecting performance degradation and enabling root-cause analysis. We present an implementation and evaluation of AutoDiagn that interacts with a Hadoop cluster deployed on a public cloud and tested with real-world benchmark applications. Experimental results show that AutoDiagn can offer a high accuracy root-cause analysis framework, at the same time as offering a small resource footprint, high throughput, and low latency.

Smart Contract Design Considerations for SLA Compliance Assessment in the Context of IoT. (Winner: Best paper candidate award).

2021 IEEE International Conference on Smart Internet of Things (IEEE SmartIoT2021)

A. Alzubaidi, K. Mitra, E. Solaiman


One of the main drivers behind blockchain adoption is a lack of trust among entities serving a common goal, but with different interests. Following the success of Bitcoin, several blockchain platforms have emerged, such as Ethereum and Hyperledger Fabric, to enable conducting distrusted processes in a non-repudiable manner. However, it is not safe to assume the applicability of conventional software design strategies to Blockchain-based solutions. In this paper, we assume an untrusted SLA (service level agreement) relationship between an IoT service provider and its consumer. We adopt Hyperledger Fabric for the purpose of implementing SLA compliance assessment. We design a smart contract that takes blockchain unique features into consideration. The design particularly accounts for the MVCC (multiversion concurrency control) mechanism, which while effective for resolving the double spending problem, causes read-write conflicts when high transmission rates are experienced between the IoT application and the blockchain. Using a fire station event monitoring scenario, we describe our smart contract design and solution for conflicting transactions. We experimentally evaluate our solution and demonstrate clear performance improvements in terms of throughput and latency.

Toward Distributed, Global, Deep Learning Using IoT Devices

IEEE Internet Computing, vol. 25, no. 3, pp. 6-12, 1 May-June 2021

B. Sudharsan et al


Deep learning (DL) using large scale, high-quality IoT datasets can be computationally expensive. Utilizing such datasets to produce a problem-solving model within a reasonable time frame requires a scalable distributed training platform/system. We present a novel approach where to train one DL model on the hardware of thousands of mid-sized IoT devices across the world, rather than the use of GPU cluster available within a data center. We analyze the scalability and model convergence of the subsequently generated model, identify three bottlenecks that are: high computational operations, time consuming dataset loading I/O, and the slow exchange of model gradients. To highlight research challenges for globally distributed DL training and classification, we consider a case study from the video data processing domain. A need for a two-step deep compression method, which increases the training speed and scalability of DL training processing, is also outlined. Our initial experimental validation shows that the proposed method is able to improve the tolerance of the distributed training process to varying internet bandwidth, latency, and Quality of Service metrics.

A Survey on Evaluating the Quality of Autonomic Internet of Things Applications

IEEE Communications Surveys & Tutorials, 2022, doi: 10.1109/COMST.2022.3205377

K. Fizza, A. Banerjee, P.P. Jayaraman, N. Auluck, R. Ranjan, K. Mitra; D. Georgakopoulos


The rapid evolution of the Internet of Things (IoT) facilitates the development of IoT applications in domains such as manufacturing, smart cities, retail, agriculture, etc. Such IoT applications collect data, analyze, and extract insightful information to enable decision-making and actuation. There is an unprecedented growth of IoT applications that automate decision-making and actuation without requiring human intervention, which we term autonomic IoT applications. The increasing scale of such applications necessitates holistic measurement and evaluation of application quality. Existing literature has evaluated quality from an end-user perspective, which may be unsuitable when dealing with the complexity of modern IoT applications, especially when they are autonomic. In this paper, we refer to IoT application quality as the aggregate quantitative value of various IoT quality metrics measured at each stage of the autonomic IoT application life cycle. We present an in-depth survey of current state-of-the-art techniques and approaches for evaluating quality of IoT applications. In particular, we survey various definitions to identify the factors that contribute to understanding and evaluating quality in IoT. Furthermore, we present open issues and identify future research directions towards realizing fine-grained quality evaluation of IoT applications. We envision that the identified research directions will, in turn, enable real-time diagnostics of IoT applications and make them quality-aware. This survey can serve as the basis for designing and developing modern, resilient quality-aware autonomic IoT applications.

Subjective Quality of Experience Assessment in Mobile Cloud Games

Proceedings of the 2022 IEEE Global Communications Conference (IEEE Globecom)

H.S. Rossi, N. Ögren, K. Mitra, I. Cotanis, C. Åhlund, and P. Johansson


The rise of mobile cloud gaming (MCG) has necessitated understanding its impact on mobile network design and deployment for end users’ QoE maximization. MCG is a dynamic service that requires stringent quality from network operators. Therefore, this paper investigates the subjective QoE of MCG over mobile networks played on smartphones. We conducted subjective tests (N=31); our results indicate that MCG is affected differently by QoS attributes such as packet loss (PL), round trip time (RTT) and jitter compared to cloud games and online mobile games. We identify that RTT values above 100 milliseconds significantly impact users’ QoE, measured via the mean opinion score (MOS). Further, lower RTT values with high PL; and higher RTT values with low PL cause a strong negative effect on MOS. Lastly, bursty jitter seems to affect the MOS, while random jitter does not significantly impact MOS.

Multi-Armed Bandits for Sleep Recognition of Elderly Living in Single-Resident Smart Homes

Zahraa Khais Shahid, Saguna Saguna, Christer Åhlund


Sleep is an essential activity that affects an individual’s health and ability to perform Activities of Daily Living (ADL). Inadequate sleep reduces cognitive capacity and leads to health-related issues such as cardiovascular diseases. Sleep disorders are more prevalent in older adults. Therefore, it is essential to recognize sleep patterns and support older adults and their caregivers. In our study, we collect data in real-world unconstrained and non-intrusive environments. This paper presents a novel sleep activity recognition method using motion sensors for recognizing nighttime and daytime sleep, which can further enable the development of insightful healthcare applications. The research objectives are to evaluate the application of using Multi-Armed Bandit methods to (i) learn normal sleep patterns, (ii) evaluate sleep quality, and (iii) detect anomalies in sleep activity for 11 elderly participants living in single-resident smart homes. We evaluate the performance of Thompson Sampling, Random Selection, and Upper Confidence Bound MAB methods. Thompson Sampling outperformed the other two methods. Our findings show most elderly participants slept between 6 and 8 hours with 85% sleep efficiency and up to 3 awakenings per night.

Forecasting Electricity and District Heating Consumption: A Case Study in Schools in Sweden

2023 IEEE Green Technologies Conference (GreenTech)

Zahraa Khais Shahid, Saguna Saguna, Christer Åhlund


The growing population and demand for new public buildings contribute to increased energy consumption and greenhouse emissions. In Sweden, the largest amount of energy is consumed in school buildings, i.e., where schools form the highest number of public properties (30 million m 2 ). In total, schools consumed 4 222 GWh of district heating and about 3 GWh of electricity for heating and other purposes in 2020. These figures lead to the realization of the need to apply effective measures to meet the European Green Deal target for 2030. Accurately forecasting energy usage is important for all stakeholders to conduct economic analysis and optimize decision-making. It is equally important in maintenance operations to allocate resources and enable the staff and students to adjust their behaviours and address the issues in buildings where peak forecasts occur. This paper develops and evaluates a power and district heating consumption for a single day and multiple days forecasting using Multivariate Recurrent Neural Network (RNN) -Long-Short term memory (LSTM) and convolutional neural networks (CNNs) and Autoencoders (AE), using daily real consumption data of six public schools provided by Skelefteå municipality in Sweden. The experimental results demonstrate that the hybrid model CNN-LSTM has achieved good accuracy compared to others, with RMSE and nRMSE error between 18%-25% and 5%-6% for electricity, respectively, and between 20%-30% RMSE and 5% nRMSE for district heating.

An energy trading framework using smart contracts

IEEE Green Technologies Conference (IEEE-Green)

Vidya Krishnan Mololoth, Christer Åhlund, Saguna Saguna


The adoption of blockchain in various industries is gaining more popularity, especially in the energy industry. With the increase of distributed energy resources (DER), energy users can generate, store, and trade their resources with others. Utility companies or energy users are influenced by blockchain-based peer-to-peer (P2P) energy trading markets. Blockchain adds transparency and immutability to the involved transactions. Smart contracts in blockchain automatically execute when the conditions are met without any third-party intervention. Motivated by these benefits, in this paper an energy trading framework is developed using Ethereum smart contracts. Energy users can trade their excess energy or buy energy using the smart contract functions. Smart contract written in solidity is compiled and deployed using remix with injected metamask provider. Ganache is used to create accounts and these accounts are imported to metamask for signing transactions. We also discuss alternative methods for smart contract deployment. Computational cost analysis is performed by evaluating the gas consumption analysis for the smart contract functions. for district heating.

A conceptual architecture for simulating blockchain-based IoT ecosystems

Journal of Cloud Computing, Article number: 103 (2023)

A. Albshri, A. Alzubaidi, M. Alharby, B. Awaji, K. Mitra and E. Solaiman


Recently, the convergence between Blockchain and IoT has been appealing in many domains including, but not limited to, healthcare, supply chain, agriculture, and telecommunication. Both Blockchain and IoT are sophisticated technologies whose feasibility and performance in large-scale environments are difficult to evaluate. Consequently, a trustworthy Blockchain-based IoT simulator presents an alternative to costly and complicated actual implementation. Our primary analysis finds that there has not been so far a satisfactory simulator for the creation and assessment of blockchain-based IoT applications, which is the principal impetus for our effort. Therefore, this study gathers the thoughts of experts about the development of a simulation environment for blockchain-based IoT applications. To do this, we conducted two different investigations. First, a questionnaire is created to determine whether the development of such a simulator would be of substantial use. Second, interviews are conducted to obtain participants’ opinions on the most pressing challenges they encounter with blockchain-based IoT applications. The outcome is a conceptual architecture for simulating blockchain-based IoT applications that we evaluate using two research methods; a questionnaire and a focus group with experts. All in all, we find that the proposed architecture is generally well-received due to its comprehensive range of key features and capabilities for blockchainbased IoT purposes.

A blockchain-based SLA monitoring and compliance assessment for IoT ecosystems

Journal of Cloud Computing: Advances, Systems and Applications, Vol. 12, No. 50, (2023)

A. Alzubaidi, K. Mitra and E. Solaiman


A Service Level Agreement (SLA) establishes the trustworthiness of service providers and consumers in several domains; including the Internet of Things (IoT). Given the proliferation of Blockchain technology, we find it compelling to reconsider the assumption of trust and centralised governance typically practised in SLA management including monitoring, compliance assessment, and penalty enforcement. Therefore, we argue that, such critical tasks should be operated by blockchain-based smart contracts in a non-repudiable manner beyond the influence of any SLA party. This paper envisions an IoT scenario wherein a firefighting station outsources end-to-end IoT operations to a specialised service provider. The contractual relationship between them is governed by an SLA which stipulates a set of quality requirements and violation consequences. The main contribution of this paper lies in designing, deploying and empirically experimenting a novel blockchain-based SLA monitoring and compliance assessment framework in the context of IoT. This is done by utilising Hyperledger Fabric (HLF), an enterprise-grade blockchain technology. Our work highlights a set of considerations and best practice at two sides, the IoT application monitoring-side and the blockchain-side. Moreover, it experimentally validates the reliability of the proposed monitoring approach, which collects relevant metrics from each IoT component and examines them against the quality requirements stated in the SLA. Finally, we propose a novel design for smart contracts at the blockchain-side, analyse and benchmark the performance, and demonstrate that the new design proves to successfully handle Multiversion Concurrency Control (MVCC) conflicts typically encountered in blockchain applications, while maintaining sound throughput and latency.

A Multi-platform Tool for Conducting QoE Subjective Tests

Proceedings of The 15th International Conference on Quality of Multimedia Experience June 20-22, 2023

H.S. Rossi, K. Mitra, C. Åhlund, N. Ögren, I. Cotanis, and P. Johansson


Quality of Experience (QoE) subjective assessment often demands setting up expensive lab experiments that involve controlling several software programs and services. In addition, these experiments may pose significant challenges regarding man-agement of testbed software components as they may have to be synchronized for efficient data collection, leading to human errors or loss of time. Further, maintaining error-free repeatability between subsequent subjective tests and comprehensive data collection is essential. Therefore, this paper proposes, develops and validates ALTRUIST, a multi-platform tool that assists the experimenter in conducting subjective tests by controlling external applications, facilitates data collection and automates test execution for conducting repeatable subjective tests in broad application areas.