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Mehrdad Salimitari

Bio: Mehrdad Salimitari is an academic researcher from University of Central Florida. The author has contributed to research in topics: Cryptocurrency & Expected utility hypothesis. The author has an hindex of 8, co-authored 14 publications receiving 187 citations.

Papers
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Posted Content
TL;DR: This article discusses and surveys the various blockchain based consensus methods that are applicable to resource constrained IoT devices and networks, and explores the possibility of utilizing them to realize a blockchain based IoT network.
Abstract: The success of blockchain as the underlying technology for cryptocurrencies has opened up possibilities for its use in other application domains as well. The main advantages of blockchain for its potential use in other domains are its inherent security mechanisms and immunity to different attacks. A blockchain relies on a consensus method for agreeing on any new data. Most of the consensus methods which are currently used for the blockchain of different cryptocurrencies require high computational power and thus are not apt for resource-constrained systems. In this article, we discuss and survey the various blockchain based consensus methods that are applicable to resource constrained IoT devices and networks. A typical IoT network consists of several devices which have limited computational and communications capabilities. Most often, these devices cannot perform intensive computations and are starved for bandwidth. Therefore, we discuss the possible measures that can be taken to reduce the computational power and convergence time for the underlying consensus methods. We also talk about some of the alternatives to the public blockchain like private blockchain and tangle, along with their potential adoption for IoT networks. Furthermore, we review the existing consensus methods that have been implemented and explore the possibility of utilizing them to realize a blockchain based IoT network. Some of the open research challenges are also put forward.

73 citations

Journal ArticleDOI
20 Apr 2020
TL;DR: This article surveys the various blockchain-based consensus methods that are applicable to resource-constrained IoT devices and networks, and discusses the possible measures that can be taken to reduce the computational power and convergence time for the underlying consensus methods.
Abstract: The success of blockchain as the underlying technology for cryptocurrencies has opened up possibilities for its use in other application domains as well. The main advantages of blockchain for its potential use in other areas are its inherent security mechanisms and immunity to data manipulation attacks. A blockchain relies on a consensus method for agreeing on any new data. Most of the consensus methods which are currently used for the blockchain of different cryptocurrencies require high computational power and thus are not suitable for resource-constrained systems. In this article, we survey the various blockchain-based consensus methods that are applicable to resource-constrained IoT devices and networks. In a typical IoT network, there exist several devices with limited computational and communication capabilities. Most often, these devices cannot perform intensive computations and are starved for bandwidth. Therefore, we discuss the possible measures that can be taken to reduce the computational power and convergence time for the underlying consensus methods. We also talk about some of the alternatives to the public blockchain, such as private blockchain and tangle, along with their potential adoption for IoT networks. Furthermore, we review the existing consensus methods that have been implemented and explore the possibility of utilizing them to realize a blockchain-based IoT network. Some of the open research challenges including AI-enabled blockchains are also put forward.

49 citations

Proceedings ArticleDOI
01 Oct 2017
TL;DR: This paper uses prospect theory to predict the profit that a specific miner, given his hash rate power and electricity costs, is expected to make from each pool, and shows how the utility values from a pool varies with electricity fee and dollar equivalent of a Bitcoin.
Abstract: It is predicted that cryptocurrencies will play an important role in the global economy. Therefore, it is prudent for us to understand the importance and monetary value of such cryptocurrencies, and strategize our investments accordingly. One of the ways to obtain cryptocurrency is via mining. As solo mining is not possible because of the computational requirements, pool mining has gained popularity. In this paper, we focus on Bitcoin and its pools. With more than 20 pools in the network of Bitcoin and other cryptocurrencies, it becomes challenging for a new miner to decide the pool he must join such that the profit is maximized. We use prospect theory to predict the profit that a specific miner, given his hash rate power and electricity costs, is expected to make from each pool. A utility value is calculated for each pool based on its recent performance, hash rate power, total number of the pool members, reward distribution policy of the pool, electricity fee in the new miner's region, pool fee, and the current Bitcoin value. Then, based on these parameters during a certain time duration, the most profitable pool is found for that miner. We show how the utility values from a pool varies with electricity fee and dollar equivalent of a Bitcoin. To find the accuracy of our predictions, we mine Bitcoin by joining 5 different pools- AntPool, F2Pool, BTC.com, Slushl'ool, and BatPool. Using an Antminer 55 for each pool, we mine Bitcoin for 40 consecutive days. Results reveal that our prospect theoretic predictions are consistent with what we actually mine; however predictions using expected utility theory are not as close.

45 citations

Posted Content
14 Sep 2018
TL;DR: This article discusses and surveys the various blockchain based consensus methods that are applicable to resource constrained IoT devices and networks, and discusses the existing consensus methods and blockchain implementations and explores the possibility of utilizing them to realize a blockchain based IoT network.
Abstract: The success of blockchain as the underlying technology for cryptocurrencies has opened up possibilities for its use in other application domains as well The main advantages of blockchain for its potential use in other domains are its inherent security mechanisms and immunity to different attacks A blockchain relies on a consensus method for agreeing on any new data Most of the consensus methods which are currently used for the blockchain of different cryptocurrencies require high computational power and thus are not apt for resource constrained systems In this article, we discuss and survey the various blockchain based consensus methods that are applicable to resource constrained IoT devices and networks A typical IoT network consists of several devices which have limited computational and communications capabilities Most often, these devices cannot perform the intensive computations and are starved for bandwidth Therefore, we discuss the possible measures that can be taken to reduce the computational power and convergence time for the underlying consensus methods We also discuss some of the alternatives to the public blockchain like private blockchain and tangle, and their potential adoption for IoT networks Furthermore, we discuss the existing consensus methods and blockchain implementations and explore the possibility of utilizing them to realize a blockchain based IoT network Some of the open research challenges are also put forward

34 citations

Proceedings ArticleDOI
01 Nov 2017
TL;DR: A Bayesian inference model and a prospect theoretic framework for data integrity scoring that quantify the trustworthiness of data collected from IoT devices by a hub in the presence of an adversary manipulating data and an imperfect anomaly monitoring mechanism is proposed.
Abstract: As Internet of Things (IoT) and Cyber-Physical systems become more ubiquitous and an integral part of our daily lives, it is important that we are able to trust the data aggregate from such systems. However, the interpretation of trustworthiness is contextual and varies according to the risk tolerance attitude of the concerned application and varying levels of uncertainty associated with the evidence upon which trust models act. Hence, the data integrity scoring mechanisms should have provisions to adapt to varying risk attitudes and uncertainties. In this paper, we propose a Bayesian inference model and a prospect theoretic framework for data integrity scoring that quantify the trustworthiness of data collected from IoT devices by a hub in the presence of an adversary manipulating data and an imperfect anomaly monitoring mechanism. The monitoring mechanism monitors the data being sent from each device and classifies the outcome as not compromised, compromised, and cannot be inferred. These outcomes are conceptualized as a multinomial hypothesis of a Bayesian inference model with three parameters which are then used for calculating a utility value on how reliable the aggregate data is. We use prospect theory inspired approach to quantify this data integrity score and evaluate trustworthiness of the aggregate data from the IoT framework. As decisions are based on how the data is fused, we propose two measuring models-one optimistic and another conservative. The proposed framework is validated using extensive simulation experiments. We show how data integrity scores vary under a variety of system factors like attack intensity and inaccurate detection.

25 citations


Cited by
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Journal ArticleDOI
TL;DR: This article gives an architecture overview of popular IoT-blockchain systems by analyzing their network structures and protocols, discusses variant consensus protocols for IoT blockchains, and makes comparisons among different consensus algorithms.
Abstract: Blockchain technology can be extensively applied in diverse services, including online micro-payments, supply chain tracking, digital forensics, health-care record sharing, and insurance payments. Extending the technology to the Internet of things (IoT), we can obtain a verifiable and traceable IoT network. Emerging research in IoT applications exploits blockchain technology to record transaction data, optimize current system performance, or construct next-generation systems, which can provide additional security, automatic transaction management, decentralized platforms, offline-to-online data verification, and so on. In this article, we conduct a systematic survey of the key components of IoT blockchain and examine a number of popular blockchain applications. In particular, we first give an architecture overview of popular IoT-blockchain systems by analyzing their network structures and protocols. Then, we discuss variant consensus protocols for IoT blockchains, and make comparisons among different consensus algorithms. Finally, we analyze the traffic model for P2P and blockchain systems and provide several metrics. We also provide a suitable traffic model for IoT-blockchain systems to illustrate network traffic distribution.

217 citations

Journal ArticleDOI
TL;DR: A comparative and analytical review on the state-of-the-art blockchain consensus algorithms is presented to enlighten the strengths and constraints of each algorithm.
Abstract: How to reach an agreement in a blockchain network is a complex and important task that is defined as a consensus problem and has wide applications in reality including distributed computing, load balancing, and transaction validation in blockchains. Over recent years, many studies have been done to cope with this problem. In this paper, a comparative and analytical review on the state-of-the-art blockchain consensus algorithms is presented to enlighten the strengths and constraints of each algorithm. Based on their inherent specifications, each algorithm has a different domain of applicability that yields to propose several performance criteria for the evaluation of these algorithms. To overview and provide a basis of comparison for further work in the field, a set of incommensurable and conflicting performance evaluation criteria is identified and weighted by the pairwise comparison method. These criteria are classified into four categories including algorithms’ throughput, the profitability of mining, degree of decentralization and consensus algorithms vulnerabilities and security issues. Based on the proposed framework, the pros and cons of consensus algorithms are systematically analyzed and compared in order to provide a deep understanding of the existing research challenges and clarify the future study directions.

216 citations

Journal ArticleDOI
TL;DR: This survey unroll and structure the blockchain related discoveries and scientific results in many aspects and classify blockchain technologies into four layers and carries out a comprehensive study on the consensus strategies, the network, and the applications of blockchain.
Abstract: As an innovated and revolutionized technology, blockchain has been applied in many fields, such as cryptocurrency, food traceability, identity management, or even market prediction. To discover its great potential, both industry and academia have paid great attention to it and numerous researches have been conducted. Based on the literature and industry whitepapers, in this survey, we unroll and structure the blockchain related discoveries and scientific results in many aspects. Particularly, we classify blockchain technologies into four layers and carry out a comprehensive study on the consensus strategies, the network, and the applications of blockchain. Different blockchain applications are put into the corresponding categories based on the fields, especially in Internet of Things (IoT). When introducing each layer, we not only organize and summarize the related works, but also discuss the fundamental issues and future research directions. We hope this survey could shed some light on the research of blockchain and serve as a guide for further studies.

210 citations

Journal ArticleDOI
TL;DR: A data-flow architecture that combines the IoT with blockchain, called IoBHealth, that can be used for storing, accessing, and managing of e-healthcare data is proposed.
Abstract: Internet of Things (IoT) and blockchain technologies are being heavily exploited and used in may domains, especially for e-healthcare. In healthcare, IoT devices have the ability to provide real-time sensory data from patients to be processed and analyzed. Collected IoT data are subjected to centralized computation, processing, and storage. Such centralization can be problematic, as it can be a single point of failure, mistrust, data manipulation and tampering, and privacy evasion. Blockchain can solve such serious problems by providing decentralized computation and storage for IoT data. Therefore, the integration IoT and blockchain technologies can become a reasonable choice for the design of a decentralized IoT-based e-healthcare systems. In this article, first, we give a brief background on blockchain. Second, popular consensus algorithms used in blockchain are discussed in the context of e-health. Third, blockchain platforms are reviewed for their appropriateness in IoT-based e-healthcare. Finally, few use cases are methodologically given to show how key features of the IoT and blockchain can be leveraged to support healthcare services and ecosystems. We also propose a data-flow architecture that combines the IoT with blockchain, called IoBHealth , that can be used for storing, accessing, and managing of e-healthcare data.

179 citations

Journal ArticleDOI
TL;DR: How Blockchain and Artificial Intelligence fuse with it through investigating the state-of-the-art studies across the metaverse components, digital currencies, AI applications in the virtual world, and blockchain-empowered technologies is discussed.
Abstract: Metaverse as the latest buzzword has attracted great attention from both industry and academia. Metaverse seamlessly integrates the real world with the virtual world and allows avatars to carry out rich activities including creation, display, entertainment, social networking, and trading. Thus, it is promising to build an exciting digital world and to transform a better physical world through the exploration of the metaverse. In this survey, we dive into the metaverse by discussing how Blockchain and Artificial Intelligence (AI) fuse with it through investigating the state-of-the-art studies across the metaverse components, digital currencies, AI applications in the virtual world, and blockchain-empowered technologies. Further exploitation and interdisciplinary research on the fusion of AI and Blockchain towards metaverse will definitely require collaboration from both academia and industries. We wish that our survey can help researchers, engineers, and educators build an open, fair, and rational future metaverse.

158 citations