【Author】 Quiroga-Garcia, Raquel Pariente-Martinez, Natalia Arenas-Parra, Mar

【Source】FINANCE RESEARCH LETTERS

【影响因子】9.848

【主题类别】

区块链治理-市场治理-数字货币

【Abstract】This paper analyses the relationship between price clustering and trade volume in the Ether, Ripple and Litecoin cryptocurrencies. We examine at which digits price clustering exists and study the behaviour at different price levels and time frames. By using recent data to provide an updated view of price clustering in the cryptocurrency market, we find a remarkable level of price clustering at round prices: 5.29%, 2.84% and 2.97% for Ether, Ripple and Litecoin for every one minute at open prices, respectively. This paper reaffirms the negotiation hypothesis by finding that price clustering appears at prices at which traded volume is higher.

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【Keywords】Cryptocurrencies; Cluster; Volume; Intraday prices

【发表时间】2022

【收录时间】2022-07-31

【文献类型】 实证性文章

【DOI】 10.1016/j.frl.2022.102811

【Author】 Akhtaruzzaman, Md Boubaker, Sabri Nguyen, Duc Khuong Rahman, Molla Ramizur

【Source】FINANCE RESEARCH LETTERS

【影响因子】9.848

【主题类别】

区块链治理-市场治理-数字货币

【Abstract】We use the Conditional Value-at-Risk (CoVaR) model to develop the systemic contagion index (SCI) for cryptocurrencies and examine their spillover effects. The SCI exhibits the highest value during the COVID-19 period, indicating evidence of pandemic-driven contagion channels. Similarly, cryptocurrency systemic networks show that the COVID-19 period induced increased interconnections, highlighting a higher number of systemic contagion channels. Our study has practical implications for investors to identify the systemic vulnerability of each cryptocurrency and make informed decisions during the crisis and non-crisis periods.

你可以尝试使用大模型来生成摘要 立即生成

【Keywords】Cryptocurrencies; Systemic risk; Contagion; Systemic network; CoVaR; COVID-19

【发表时间】2022

【收录时间】2022-07-31

【文献类型】 理论性文章

【DOI】 10.1016/j.frl.2022.102787

【Author】 Apergis, Nicholas

【Source】FINANCE RESEARCH LETTERS

【影响因子】9.848

【主题类别】

区块链治理-市场治理-数字货币

【Abstract】This paper analyzes the role of COVID-19 pandemic crisis in determining and forecasting conditional volatility returns for a set of eight cryptocurrencies through an asymmetric GARCH modeling approach. The findings report that the COVID-19 pandemic exerts a positive effect on the conditional volatility of those returns, while explicitly considering the pandemic event improves volatility predictions.

你可以尝试使用大模型来生成摘要 立即生成

【Keywords】Cryptocurrency returns; COVID-19; Conditional volatility

【发表时间】2022

【收录时间】2022-07-31

【文献类型】 实证性文章

【DOI】 10.1016/j.frl.2021.102659

【Author】 Jiang, Wen Xu, Qiuhua Zhang, Ruige

【Source】FINANCE RESEARCH LETTERS

【影响因子】9.848

【主题类别】

区块链治理-市场治理-数字货币

【Abstract】We investigate the tail risk spillover effects between cryptocurrencies and conventional assets from a systemic risk perspective, by constructing a large tail-event driven network. The results provide strong evidence for the existence of tail-risk spillovers, which challenges most literature stating the detachment of Bitcoin from traditional assets. Moreover, this paper finds two significant network factors in explaining the return of cryptocurrencies. Specifically, the risk contagion occurs under extreme market conditions, while the network diversification happens only when the market is under distress. Further sub-market analysis finds that cryptocurrencies are impacted more than stocks by the massive selloff during bear markets.

你可以尝试使用大模型来生成摘要 立即生成

【Keywords】Cryptocurrency; CoVaR; Network; Adjacency matrix; Risk spillover; Systemic risk

【发表时间】2022

【收录时间】2022-07-31

【文献类型】 实证性文章

【DOI】 10.1016/j.frl.2021.102424

【Author】 Chowdhury, Md Shahedur R. Damianov, Damian S. Elsayed, Ahmed H.

【Source】FINANCE RESEARCH LETTERS

【影响因子】9.848

【主题类别】

区块链治理-市场治理-数字货币

【Abstract】Using a quantile vector autoregressive model to capture return dynamics in extreme market conditions, we find that the cryptocurrency market exhibits a high level of market connectedness. Bitcoin is a net transmitter of return spillovers during busts and a net receiver during booms. Analysis of the timing of bubble and crash periods uncovers the presence of interdependence and contagion effects. Asset dynamics is driven to a great extent by the technology, in particular the consensus protocol of cryptocurrencies. There is only limited evidence for asset rotation, and it involves mostly Ripple.

你可以尝试使用大模型来生成摘要 立即生成

【Keywords】Cryptocurrencies; Interdependence; Contagion; Rotation; Bubbles; Crashes

【发表时间】2022

【收录时间】2022-07-31

【文献类型】 实证性文章

【DOI】 10.1016/j.frl.2021.102494

【Author】 Nakagawa, Kei Sakemoto, Ryuta

【Source】FINANCE RESEARCH LETTERS

【影响因子】9.848

【主题类别】

区块链治理-市场治理-数字货币

【Abstract】Both cryptocurrencies and gold are scarce, expensive for extraction, and less affected by money supply. We focus on these similarities and investigate whether cryptocurrency network affects impact on expected return on gold. Our results show that the number of cryptocurrency wallet users is positively related to the expected return on gold. Moreover, we employed a machine-learning approach and considered the interactions among predictors. We reveal that network factors have a greater impact on gold than returns on Bitcoin and other macroeconomic and financial variables.

你可以尝试使用大模型来生成摘要 立即生成

【Keywords】Gold; Precious metals; Network factors; Cryptocurrencies; Machine learning

【发表时间】2022

【收录时间】2022-07-31

【文献类型】 实证性文章

【DOI】 10.1016/j.frl.2021.102375

【Author】 Chuffart, Thomas

【Source】FINANCE RESEARCH LETTERS

【影响因子】9.848

【主题类别】

区块链治理-市场治理-数字货币

【Abstract】Using a Smooth Transition Conditional Correlation model with Google search data as a transition variable, I investigate correlation dynamics between a set of crypto-currencies. A major change in the correlation dynamics after the 2017 bubble burst is explained by the attention subsequently surrounding cryptocurrencies. Google searches are found to be a good predictor of correlation between cryptocurrencies and could provide useful input to portfolio management.

你可以尝试使用大模型来生成摘要 立即生成

【Keywords】Bitcoin; Cryptocurrencies; Conditional correlations; Google searches data

【发表时间】2022

【收录时间】2022-07-31

【文献类型】 实证性文章

【DOI】 10.1016/j.frl.2021.102239

【Author】 Mandaci, Pinar Evrim Cagli, Efe Caglar

【Source】FINANCE RESEARCH LETTERS

【影响因子】9.848

【主题类别】

区块链治理-市场治理-数字货币

【Abstract】This paper investigates whether herding is present before and during the COVID-19 pandemic, analyzing intraday data of Bitcoin and eight altcoins. The herding intensity measure of Patterson and Sharma (2006) is calculated for the first time for cryptocurrency markets. Furthermore, we employed a novel Granger causality methodology with a Fourier approximation to determine the relationship between herding and volatility, considering the structural breaks. Our results indicate a significant herding behavior, concentrating during the COVID-19 outbreak. The causality test results show that herding has a significant effect on market volatility. Our results do not support the efficient market hypothesis.

你可以尝试使用大模型来生成摘要 立即生成

【Keywords】Herding; Bitcoin; Cryptocurrencies; Behavioral finance; COVID-19

【发表时间】2022

【收录时间】2022-07-31

【文献类型】 实证性文章

【DOI】 10.1016/j.frl.2021.102382

【Author】 Hasan, Md Bokhtiar Hassan, M. Kabir Karim, Zulkefly Abdul Rashid, Md Mamunur

【Source】FINANCE RESEARCH LETTERS

【影响因子】9.848

【主题类别】

区块链治理-市场治理-数字货币

【Abstract】We analyze the cryptocurrency policy uncertainty (UCRY Policy) effect on gold, Bitcoin, the US dollar, DJ Islamic Index, Sukuk, and WTI returns. Using Ordinary Least Square, Quantile regression, and Quantile-on-Quantile regression approaches, we find that Bitcoin, the US dollar, and WTI returns are negatively impacted by UCRY Policy during the bearish and bullish states, suggesting their failure to act as a hedge or safe-haven asset. Conversely, UCRY Policy positively impacts gold, DJ Islamic Index, and Sukuk returns, highlighting their potential to function as a hedge or safe-haven asset. Gold serves the same role during highly uncertain times.

你可以尝试使用大模型来生成摘要 立即生成

【Keywords】Cryptocurrency policy uncertainty; Hedge; Safe-haven; Quantile-on-Quantile

【发表时间】2022

【收录时间】2022-07-31

【文献类型】 实证性文章

【DOI】 10.1016/j.frl.2021.102272

【Author】 Vishwakarma, Lokendra Nahar, Ankur Das, Debasis

【Source】IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY

【影响因子】6.239

【主题类别】

区块链应用-实体经济-交通领域

【Abstract】The development of modern software-defined networking (SDN) solutions brings new opportunities in Internet-of-Vehicles (IoVs). However, the autonomous nature of the vehicular environment leads to unpredictable security vulnerabilities and reliability issues. The high computation overhead and storage requirements also pose a significant challenge in message dissemination. To overcome these issues, we introduce a lightweight blockchain-based security protocol for secure communication and storage in SDN-enabled IoV, known as LBSV. The LBSV is a permissioned blockchain network that uses the proposed modified practical byzantine fault tolerance (mPBFT) consensus algorithm. Additionally, the SDN-enabled network exploits the blockchain framework and schedules different procedures. The secure message dissemination is achieved through various cryptographic functions (i.e., elliptic curve cryptography (ECC) and the secure hash algorithm (SHA256)). The security analysis shows that the LBSV withstands various cyberattacks regarding message dissemination privacy. The experimental results show that LBSV provides high performance with 85% less computational cost, 55% less storage and communication overhead and 90% less consensus delay compared with state-of-the-art schemes.

你可以尝试使用大模型来生成摘要 立即生成

【Keywords】Blockchains; Security; Computer architecture; Secure storage; Consensus algorithm; Protocols; Authentication; Blockchain; consensus algorithm; Internet-of-Vehicle (IoV); software defined networking (SDN)

【发表时间】2022

【收录时间】2022-07-31

【文献类型】 理论性文章

【DOI】 10.1109/TVT.2022.3163960

【Author】 Ren, Xiaohang Wang, Rui Duan, Kun Chen, Jinyu

【Source】RESEARCH IN INTERNATIONAL BUSINESS AND FINANCE

【影响因子】6.143

【主题类别】

区块链治理-市场治理-数字货币

【Abstract】This paper studies evolution of the asymmetric sheltering role of Bitcoin compared to gold against oil-related uncertainties with varying severity of the COVID-19 pandemic. Using a varying-coefficient quantile approach, we find a safe haven role of Bitcoin, and it becomes gradually stronger when the pandemic intensifies. The relationship between gold and oil markets is shown to vary with changing severity of the pandemic. We find that gold acts as an increasingly weakened diversifier as the pandemic intensifies until a level, above which its diversification gains would dissipate then. In normal market conditions, both Bitcoin and gold perform as weak hedges for oil portfolios. Our findings demonstrate that interpretation of the sheltering role of Bitcoin and gold against oil market downturns would be biased unless the role dynamics in different market conditions and pandemic severity are considered. Additional analyses reassure robustness of our findings.

你可以尝试使用大模型来生成摘要 立即生成

【Keywords】Bitcoin; Crude oil market; COVID-19 pandemic; Safe haven; Gold; Varying-coefficient quantile regression

【发表时间】2022

【收录时间】2022-07-31

【文献类型】 实证性文章

【DOI】 10.1016/j.ribaf.2022.101672

【Author】 He, Jianjia Zhang, Ni

【Source】JOURNAL OF THEORETICAL AND APPLIED ELECTRONIC COMMERCE RESEARCH

【影响因子】5.318

【主题类别】

区块链技术-核心技术-智能合约

【Abstract】With the continuous cross-border cooperation among industries, the concept of an industrial interconnection supply and demand network is constantly mentioned. As industry interconnectivity continues to grow, collaboration models have changed as companies work more closely with each other, and the synergy model has changed. In order to improve the efficiency of collaboration and to promote the free allocation of resources in the trading process of the industry interconnection supply and demand network, an industry interconnection supply and demand network resource matching platform based on the Alliance blockchain was built, steps for resource trading on the platform were proposed. Using blockchain technology's smart contract technology to simplify the transaction process, the triggering mechanism and algorithm rules of smart contracts in the trading process of the platform were designed, and the smart contract code was developed, deployed, and tested using Remix IDE, and the test results showed the transaction process between the supply and demand sides. Through blockchain technology, it achieves information security and transparency in the process of resource trading in the industry interconnection supply and demand network, establishes a trust mechanism on both sides of the transaction, reduces redundant steps in the transaction and improves the operational efficiency of the industry interconnection supply and demand network by increasing the efficiency of resource allocation.

你可以尝试使用大模型来生成摘要 立即生成

【Keywords】supply and demand network; smart contracts; synergy

【发表时间】2022

【收录时间】2022-07-31

【文献类型】 理论性文章

【DOI】 10.3390/jtaer17020040

【Author】 Wu, Jie Jiang, Suhan

【Source】IEEE TRANSACTIONS ON NETWORK SCIENCE AND ENGINEERING

【影响因子】5.033

【主题类别】

区块链技术-核心技术-扩展方案

【Abstract】The lightning network (LN) is a layer-two solution in Bitcoin for support scalability. LN uses offchain micropayment channels to scale the blockchain's capability to perform instant transactions without a global block confirmation process. However, micropayment scalability in a large LN is still limited by its relatively large searching space for a suitable route. Liquidation for small nodes still remains major challenges for the LN as the amount of transactions along a channel is predetermined by the channel capacity defined by two end nodes of the channel. In this paper, we introduce the notion of supernodes and the corresponding supernodes-based pooling to address these challenges. In order to meet the high adaptivity and low maintenance cost in the dynamic LN where users join and leave, supernodes are constructed locally to avoid global information or label propagation. Each supernode, together with a subset of (non-supernodes) neighbors, forms a supernode-based pool. These pools constitute a partition of the LN. Additionally, supernodes are self-connected. Micropayment scalability is supported through node set reduction as only supernodes are involved in searching and in payment with other supernodes. Liquidation is enhanced through pooling to redistribute funds within a pool to external channels of its supernode. Extensive simulations using LN simulator CLoTH have been conducted to validate the improvement in routing scalability and liquidation of the proposed architecture under different settings.

你可以尝试使用大模型来生成摘要 立即生成

【Keywords】Blockchains; Scalability; Routing; Channel capacity; Lightning; Color; Bitcoin; Bitcoin; blockchain; lightning networks; liquidation; localized algorithms; pooling; scalability; supernodes

【发表时间】2022

【收录时间】2022-07-31

【文献类型】 实证性文章

【DOI】 10.1109/TNSE.2022.3166707

【Author】 Xi, Jinwen Zou, Shihong Xu, Guoai Lu, Yueming

【Source】PERVASIVE AND MOBILE COMPUTING CCF-C

【影响因子】3.848

【主题类别】

区块链技术-核心技术-共识机制

【Abstract】With the commercialization of fifth generation mobile networks (5G) and continuous innovation of the Internet of Things (IoT), crowdsensing, as a new emerging IoT application, has further deepened our knowledge, utilizing various smart objects distributed throughout the whole industrial system for data collection and processing. To avoid a single point of failure and ensure data integrity, blockchain technology was widely applied. However, due to the demand for computing power and resources, IoT devices with limited capabilities and resources are unsuitable for crowdsensing implementation in the blockchain network. Therefore, this paper proposes a lightweight blockchainbased crowdsensing model named CrowdLBM with a novel consensus mechanism based on global reputation to resolve the issues raised above. Furthermore, we propose a two stage scheme and two types of smart contracts to support the crowdsensing process automatically without the intervention of any third party. Finally, we implement a blockchain prototype on Hyperledger Sawtooth, extensive experimental results show that the proposed CrowdLBM outperforms other crowdsensing systems in terms of both scalability and security.(C) 2022 Elsevier B.V. All rights reserved.

你可以尝试使用大模型来生成摘要 立即生成

【Keywords】Internet of Things; Crowdsensing; Lightweight consensus mechanism; Global reputation; Smart contract

【发表时间】2022

【收录时间】2022-07-31

【文献类型】 理论性文章

【DOI】 10.1016/j.pmcj.2022.101623

【Author】 Mendi, Arif Furkan

【Source】SENSORS

【影响因子】3.847

【主题类别】

区块链技术-核心技术-智能合约

【Abstract】Traditional sentiment analysis methods are based on text-, visual- or audio-processing using different machine learning and/or deep learning architecture, depending on the data type. This situation comes with technical processing diversity and cultural temperament effect on analysis of the results, which means the results can change according to the cultural diversities. This study integrates a blockchain layer with an LSTM architecture. This approach can be regarded as a machine learning application that enables the transfer of the metadata of the ledger to the learning database by establishing a cryptographic connection, which is created by adding the next sentiment with the same value to the ledger as a smart contract. Thus, a "Proof of Learning" consensus blockchain layer integrity framework, which constitutes the confirmation mechanism of the machine learning process and handles data management, is provided. The proposed method is applied to a Twitter dataset with the emotions of negative, neutral and positive. Previous sentiment analysis methods on the same data achieved accuracy rates of 14% in a specific culture and 63% in a the culture that has appealed to a wider audience in the past. This study puts forth a very promising improvement by increasing the accuracy to 92.85%.

你可以尝试使用大模型来生成摘要 立即生成

【Keywords】sentiment analysis; blockchain; smart contracts; machine learning

【发表时间】2022

【收录时间】2022-07-31

【文献类型】 实证性文章

【DOI】 10.3390/s22124419

【Author】 Liu, Wei Zhang, Xuhao Feng, Wenlong Huang, Mengxing Xu, Yun

【Source】SENSORS

【影响因子】3.847

【主题类别】

区块链技术-核心技术-共识机制

【Abstract】In service-transaction scenarios, blockchain technology is widely used as an effective tool for establishing trust between service providers and consumers. The consensus algorithm is the core technology of blockchain. However, existing consensus algorithms, such as the practical Byzantine fault tolerance (PBFT) algorithm, still suffer from high resource consumption and latency. To solve this problem, in this study, we propose an improved PBFT blockchain consensus algorithm based on quality of service (QoS)-aware trust service evaluation for secure and efficient service transactions. The proposed algorithm, called the QoS-aware trust practical Byzantine fault tolerance (QTPBFT) algorithm, efficiently achieves consensus, significantly reduces resource consumption, and enhances consensus efficiency. QTPBFT incorporates a QoS-aware trust service global evaluation mechanism that implements service reliability ranking by conducting a dynamic evaluation according to the real-time performance of the services. To reduce the traffic of the blockchain, it uses a mechanism that selects nodes with higher values to form a consensus group that votes for consensus according to the global evaluation result of the trust service. A practical protocol is also constructed for the proposed algorithm. The results of extensive simulations and comparison with other schemes verify the efficacy and efficiency of the proposed scheme.

你可以尝试使用大模型来生成摘要 立即生成

【Keywords】QoS-aware; blockchain; consensus mechanism; PBFT

【发表时间】2022

【收录时间】2022-07-31

【文献类型】 实证性文章

【DOI】 10.3390/s22124590

【Author】 Verma, Sudhani Yadav, Divakar Chandra, Girish

【Source】IEEE ACCESS

【影响因子】3.476

【主题类别】

区块链技术-核心技术-共识机制

【Abstract】As the size of data is increasing exponentially, its security is a major concern. Emerging technology like blockchain is used to provide security to systems. Since the inception of blockchain, it has been adopted by researchers and industry both, however, it gained enormous attention after cryptocurrency. It can be defined as a means of storing information in such a way that modification and hacking the system is difficult or impossible. A blockchain is a decentralized ledger that is digital and public, consisting of records of transactions called blocks. A consensus technology assures that all nodes agree on a unique sequence for appending blocks. A comprehensive examination of these algorithms will aid in understanding how and why each blockchain operates in the manner that it does. In this study, we addressed extensively used consensus techniques in the blockchain and the importance of consensus protocol in blockchain technology. The underlying consensus algorithm is a critical component of every blockchain-based system which determine the performance and security of the system. Ensuring the correctness of consensus protocols is uttermost important to create trust in the blockchain-based systems and formal methods are the way to create that trust and develop correct and verified systems. Formal modeling is a method of writing a system mathematically and examining the correctness and verifying the developed system. This study analyzed the importance of consensus mechanisms and how formal methods are helping to develop a correct blockchain-based system. The current scenario of the application of formal methods in the consensus mechanism of blockchain for their verification is presented.

你可以尝试使用大模型来生成摘要 立即生成

【Keywords】Consensus protocol; Protocols; Smart contracts; Bitcoin; Licenses; Fingerprint recognition; Distributed ledger; Blockchain; consensus protocols; distributed ledger technology; formal methods; formal verification

【发表时间】2022

【收录时间】2022-07-31

【文献类型】 理论性文章

【DOI】 10.1109/ACCESS.2022.3184799

【Author】 Wu, Wenjun Sun, Dehao Jin, Kaiqi Sun, Yang Si, Pengbo

【Source】CHINA COMMUNICATIONS

【影响因子】3.170

【主题类别】

区块链技术-协同技术-边缘计算

【Abstract】To cope with the low latency requirements and security issues of the emerging applications such as Internet of Vehicles (IoV) and Industrial Internet of Things (IIoT), the blockchain-enabled Mobile Edge Computing (MEC) system has received extensive attention. However, blockchain is a computing and communication intensive technology due to the complex consensus mechanisms. To facilitate the implementation of blockchain in the MEC system, this paper adopts the committee-based Practical Byzantine Fault Tolerance (PBFT) consensus algorithm and focuses on the committee selection problem. Vehicles and IIoT devices generate the transactions which are records of the application tasks. Base Stations (BSs) with MEC servers, which serve the transactions according to the wireless channel quality and the available computing resources, are blockchain nodes and candidates for committee members. The income of transaction service fees, the penalty of service delay, the decentralization of the blockchain and the communication complexity of the consensus process constitute the performance index. The committee selection problem is modeled as a Markov decision process, and the Proximal Policy Optimization (PPO) algorithm is adopted in the solution. Simulation results show that the proposed PPO-based committee selection algorithm can adapt to the system design requirements with different emphases and outperforms other comparison methods.

你可以尝试使用大模型来生成摘要 立即生成

【Keywords】Blockchains; Task analysis; Servers; Resource management; Industrial Internet of Things; Consensus algorithm; Real-time systems; blockchain; mobile edge computing; deep reinforcement learning; consensus mechanism

【发表时间】2022

【收录时间】2022-07-31

【文献类型】 实证性文章

【DOI】 10.23919/JCC.2022.06.005

【Author】 Wang, Ruimiao Wang, Xiaodong Yang, Wenti Yuan, Shuai Guan, Zhitao

【Source】CHINA COMMUNICATIONS

【影响因子】3.170

【主题类别】

区块链技术-核心技术-加密算法

【Abstract】The traditional centralized data sharing systems have potential risks such as single point of failures and excessive working load on the central node. As a distributed and collaborative alternative, approaches based upon blockchain have been explored recently for Internet of Things (IoTs). However, the access from a legitimate user may be denied without the pre-defined policy and data update on the blockchain could be costly to the owners. In this paper, we first address these issues by incorporating the Accountable Subgroup Multi-Signature (ASM) algorithm into the Attribute-based Access Control (ABAC) method with Policy Smart Contract, to provide a finegrained and flexible solution. Next, we propose a policy-based Chameleon Hash algorithm that allows the data to be updated in a reliable and convenient way by the authorized users. Finally, we evaluate our work by comparing its performance with the benchmarks. The results demonstrate significant improvement on the effectiveness and efficiency.

你可以尝试使用大模型来生成摘要 立即生成

【Keywords】Blockchains; Smart contracts; Internet of Things; Authorization; Data privacy; Costs; Encryption; blockchain; access control; smart contract; multi-signature; chameleon-hash; data sharing; Internet of Things

【发表时间】2022

【收录时间】2022-07-31

【文献类型】 理论性文章

【DOI】 10.23919/JCC.2022.06.003

【Author】 Yi, Yongsheng He, Mengxi Zhang, Yaojie

【Source】NORTH AMERICAN JOURNAL OF ECONOMICS AND FINANCE

【影响因子】3.136

【主题类别】

区块链治理-市场治理-数字货币

【Abstract】Inspired by cross-market information flows among international stock markets, we incorporate external predictive information from other cryptocurrency markets to forecast the realized volatility (RV) of Bitcoin. To make the most of such external information, we employ six widely accepted approaches to construct predictive models based on multivariate information. Our results suggest that the scaled principal component analysis (SPCA) approach steadily improves the predictive ability of the prevailing heterogeneous autoregressive (HAR) benchmark model considering both the model confidence set (MCS) test and the Diebold-Mariano (DM) test based on three widely accepted loss functions. The forecasting performance is persistent to various robustness checks and extensions. Notably, a mean-variance investor can obtain steady positive economic gains if the investment portfolio is constructed on the basis of the forecasts from the HAR-SPCA model. The results of this study show that external predictive information is statistically and economically important in forecasting Bitcoin RV.

你可以尝试使用大模型来生成摘要 立即生成

【Keywords】Bitcoin; Cryptocurrency; Realized volatility; Out-of-sample prediction; Scaled principal component analysis

【发表时间】2022

【收录时间】2022-07-31

【文献类型】 实证性文章

【DOI】 10.1016/j.najef.2022.101731

【Author】 Xu, Jinjie Wang, Wei Zeng, Yu Yan, Zhiwei Li, Hongtao

【Source】SYMMETRY-BASEL

【影响因子】2.940

【主题类别】

区块链技术-核心技术-共识机制

【Abstract】Raft is a fast, scalable, understandable consensus algorithm widely used in distributed systems. The Leader handles client requests and interacts with other servers to reach a consensus, so a stable, reliable, and powerful Leader is crucial for the cluster. We designed a policy-based voting mechanism to make the elected Leader as reliable as possible. In order to improve the asymmetric relationship between the Followers and Leader, we designed a mechanism to trigger a new round of the election actively so that the Leader node can actively transform into a Follower under certain conditions and enhance the symmetry between servers. Our proposed Raft-PLUS algorithm makes the elected Leader as reliable as possible through four election policies and designed three opposition policies to trigger a new round of the election. To verify the effectiveness of the Raft-PLUS algorithm, we configure different election and opposition policies on 12 servers to simulate the election and opposition process of the Leader and explain the process. To demonstrate the advantages of the Raft-PLUS algorithm, we built key-value stores based on Raft and Raft-PLUS, and we tested the performance of Raft-PLUS and the Raft algorithm in normal and abnormal states. Experimental results show that the Raft-PLUS algorithm has similar write throughput to the Raft algorithm under normal conditions. Regarding the quality of the Leader network changes, the average write throughput of the Raft-PLUS algorithm is 40% higher than that of the Raft algorithm. The Leader's CPU usage fluctuated; the average write throughput of Raft-PLUS was 38% higher than Raft.

你可以尝试使用大模型来生成摘要 立即生成

【Keywords】blockchain; consensus algorithm; Raft; leader election

【发表时间】2022

【收录时间】2022-07-31

【文献类型】 实证性文章

【DOI】 10.3390/sym14061122

【Author】 Lopes, Elio Jordan Kataria, Shaolin Keshav, Shashank Ikram, Sumaiya Thaseen Ghalib, Muhammad Rukunuddin Shankar, Achyut Krichen, Moez

【Source】WIRELESS NETWORKS CCF-C

【影响因子】2.701

【主题类别】

区块链应用-实体经济-传媒领域

【Abstract】In centralized video streaming platforms, the platform owner, rather than the content producer, controls most of the content uploaded on the centralized video platform.-Blockchain-based video streaming systems aim to create decentralized peer-to-peer networks for video streaming services with various monetization options. Video transcoding is commonly used in the video streaming industry to convert videos into numerous formats for various viewers. We argue, however, that the standard media delivery framework may be modified by an InterPlanetary File System-based delivery network with Hypertext Transfer Protocol Secure Live Streaming for any distribution model (live or on-demand). This paper examines the performance of decentralised video streaming platforms like NiftySubs, characterized by a 'pay-as-you-watch' subscription-based service paradigm, wherein the user only has to pay for the duration they watch the content on the Ethereum Blockchain. We also discuss the use of protocols like Unlock for providing access to locked content on the Blockchain, Superfluid Protocol money streams to enable actual time finance and storage of content on Content Delivery Network like InterPlanetary File System, which are based on content-based addressing mechanisms. Finally, we also discuss challenges and solutions by which the security of content can be established and maintained and how users can view accurate time usage statistics with the help of indexing solutions like the Graph Protocol.

你可以尝试使用大模型来生成摘要 立即生成

【Keywords】Blockchain; Ethereum; Smart contracts; InterPlanetary file system; Livepeer; Live video streaming; Superfluid; Textile framework; Decentralized application; Real-Time finance

【发表时间】

【收录时间】2022-07-31

【文献类型】 理论性文章

【DOI】 10.1007/s11276-022-03009-6

【Author】 Li, Dun Han, Dezhi Crespi, Noel Minerva, Roberto Li, Kuan-Ching

【Source】JOURNAL OF SUPERCOMPUTING

【影响因子】2.557

【主题类别】

区块链应用-虚拟经济-金融领域

【Abstract】Supply chain finance (SCF) provides credit for small and medium-sized enterprises with low credit lines and small financing scales. The resulting financial credit data and related business transaction data are highly confidential and private. However, traditional SCF management schemes use third-party platforms and centralized designs that cannot achieve highly reliable secure storage and fine-grained access control. To address such a need, we propose Fabric-SCF, designing and implementing a Blockchain-based secure storage system by utilizing distributed consensus to realize data security, traceability, and immutability. The attribute-based access control model is deployed for access control, also utilizing smart contracts to define system processes and access policies to ensure the system's efficient operation. To verify the performance of Fabric-SCF, two sets of simulation experiments are designed its effectiveness. Experimental results show that Fabric-SCF achieves dynamic and fine-grained access control while maintaining high throughput in a simulated real-world operating scenario.

你可以尝试使用大模型来生成摘要 立即生成

【Keywords】Blockchain; Smart contract; Supply chain finance; ABAC; Hyperledger Fabric

【发表时间】

【收录时间】2022-07-31

【文献类型】 实证性文章

【DOI】 10.1007/s11227-022-04655-5

【Author】 Xu, Guangxia Wang, Yishuai

【Source】SECURITY AND COMMUNICATION NETWORKS CCF-C

【影响因子】1.968

【主题类别】

区块链技术-核心技术-共识机制

【Abstract】The traditional PBFT consensus algorithm has several limitations in the consortium blockchain environment, such as unclear selection of primary node, excessive communication times, etc. To solve these limitations, an improved consensus algorithm VS-PBFT based on vague sets was proposed. VS-PBFT has three phases: node partition, primary node selection, and global consensus. Firstly, the nodes of the whole network are partitioned using the consistent hashing-like consensus algorithm, and then the local primary node is selected by the primary node selection algorithm in each partition. The local primary nodes run the four-phase PBFT consensus algorithm to complete the global consensus. The analysis of the VS-PBFT consistency algorithm shows that the algorithm can improve the fault-tolerant rate and reduce communication complexity, and the algorithm is dynamic; that is, node can join and quit adaptively.

你可以尝试使用大模型来生成摘要 立即生成

【Keywords】

【发表时间】2022

【收录时间】2022-07-31

【文献类型】 理论性文章

【DOI】 10.1155/2022/6144664

【Author】 Jacobetty, Pedro Orton-Johnson, Kate

【Source】SOCIAL EPISTEMOLOGY

【影响因子】1.625

【主题类别】

区块链应用-实体经济-公共管理

【Abstract】Heralded as revolutionary in their potential to improve efficiency, transparency, and sustainability, blockchain technologies promise new forms of large-scale coordination between actors that do not necessarily trust each other. This paper examines blockchain imaginaries and associated metaphors. Our analysis focuses on bitcoin and ethereum, today's most prominent blockchains that use the proof-of-work consensus mechanism. We identify three principles that organise blockchain imaginaries: substantial, morphological, and structural. These principles position blockchain as an enabler of economic, political and epistemological practices, respectively. Blockchain infrastructure and protocols rely on substantial metaphors (e.g. gold, gas) to govern resource allocation, morphological metaphors (e.g. work, trust) to generate consensus and structural metaphors (e.g. chain, transaction) to establish shared knowledge. Those imaginaries rely on metaphorical displacements of meaning that make blockchain technology relevant and intelligible while simultaneously shaping the direction of technological development and positing these technologies as new forms of economic, political and epistemological organisation. They are not merely descriptive but performative. We conclude by showing how these principles partially overlap with three symbolically generalized media: money, power and truth. Money organises scarcity within the economic system, power organises consensus within the political system, and truth organises knowledge within the science system.

你可以尝试使用大模型来生成摘要 立即生成

【Keywords】Blockchain; sociotechnical imaginaries; metaphors; digital sociology

【发表时间】

【收录时间】2022-07-31

【文献类型】 理论性文章

【DOI】 10.1080/02691728.2022.2086086

【Author】 Yin, Tao Wang, Yiming

【Source】E & M EKONOMIE A MANAGEMENT

【影响因子】1.422

【主题类别】

区块链治理-市场治理-数字货币

【Abstract】This paper mainly studies the market nonlinearity and the prediction model based on the intrinsic generation mechanism (chaos) of Bitcoin???s daily return???s volatility from June 27, 2013 to November 7, 2019 with an econophysics perspective, so as to avoid the forecasting model misspecification. Firstly, this paper studies the multifractal and chaotic nonlinear characteristics of Bitcoin volatility by using multifractal detrended fluctuation analysis (MFDFA) and largest Lyapunov exponent (LLE) methods. Then, from the perspective of nonlinearity, the measured values of multifractal and chaos show that the volatility of Bitcoin has short-term predictability. The study of chaos and multifractal dynamics in nonlinear systems is very important in terms of their predictability. The chaos signals may have short-term predictability, while multifractals and self-similarity can increase the likelihood of accurately predicting future sequences of these signals. Finally, we constructed a number of chaotic artificial neural network models to forecast the Bitcoin return???s volatility avoiding the model misspecification. The results show that chaotic artificial neural network models have good prediction effect by comparing these models with the existing Artificial Neural Network (ANN) models. This is because the chaotic artificial neural network models can extract hidden patterns and accurately model time series from potential signals, while the benchmark ANN models are based on Gaussian kernel local approximation of non-stationary signals, so they cannot approach the global model with chaotic characteristics. At the same time, the multifractal parameters are further mined to obtain more market information to guide financial practice. These above findings matter for investors (especially for investors in quantitative trading) as well as effective supervision of financial institutions by government.

你可以尝试使用大模型来生成摘要 立即生成

【Keywords】Nonlinear; multifractal; chaos; Bitcoin; prediction

【发表时间】2022

【收录时间】2022-07-31

【文献类型】 实证性文章

【DOI】 10.15240/tul/001/2022-2-007

【Author】 Choi, Jinho Kim, Jaehan Song, Minkyoo Kim, Hanna Park, Nahyeon Seo, Minjae Jin, Youngjin Shin, Seungwon

【Source】IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS

【影响因子】0.695

【主题类别】

区块链治理-市场治理-欺诈犯罪

【Abstract】Cryptocurrency abuse has become a critical problem. Due to the anonymous nature of cryptocurrency, criminals commonly adopt cryptocurrency for trading drugs and deceiving people without revealing their identities. Despite its significance and severity, only few works have studied how cryptocurrency has been abused in the real world, and they only provide some limited measurement results. Thus, to provide a more in-depth understanding on the cryptocurrency abuse cases, we present a large-scale analysis on various Bitcoin abuse types using 200,507 realworld reports collected by victims from 214 countries. We scrutinize observable abuse trends, which are closely related to real-world incidents, to understand the causality of the abuses. Furthermore, we investigate the semantics of various cryptocurrency abuse types to show that several abuse types overlap in meaning and to provide valuable insight into the public dataset. In addition, we delve into abuse channels to identify which widely-known platforms can be maliciously deployed by abusers following the COVID-19 pandemic outbreak. Consequently, we demonstrate the polarization property of Bitcoin addresses practically utilized on transactions, and confirm the possible usage of public report data for providing clues to track cyber threats. We expect that this research on Bitcoin abuse can empirically reach victims more effectively than cybercrime, which is subject to professional investigation.

你可以尝试使用大模型来生成摘要 立即生成

【Keywords】Bitcoin abuse; clustering; cryptocurrency; cyber crime; cyber threat intelligence; public data

【发表时间】2022

【收录时间】2022-07-31

【文献类型】 实证性文章

【DOI】 10.1587/transinf.2021EDP7182

【Author】 Afridi, Ahmad H. A. S. S. A. N.

【Source】COMPUTING AND INFORMATICS

【影响因子】0.455

【主题类别】

区块链应用-实体经济-工业领域

【Abstract】Cloud-based manufacturing is taking shape, and many industries seem interested to make the transition to it. Developing blockchain solutions for trusted computing is also taking its roots. Developing a blockchain-based solution for cloud based manufacturing systems is a field that is new but also faces limitations and a lack of case studies. Smart contracts are one part of the solution which deals with making blockchain successful in cloud-based manufacturing. As we move towards smart contracts design and development for cloud-based manufacturing, there is no complete survey of smart contract and cloud manufacturing that can highlight critical, challenging issues and limitations. Most of the work found in smart contracts is mostly financial and notary-centric applications. On the cloud manufacturing side, most of the literature deals with Internet of Things (IoT) and cloud computing systems. Therefore, there is a need to study the best practices to start manufacturing supported by blockchain smart contracts. We conducted a scoping review for smart contracts for cloud manufacturing to address the problem mentioned above. We studied the latest case studies and concepts in data extracted from digital libraries and online repositories. Furthermore, we follow the relevance and acceptance criteria of research articles for inclusion and exclusion from this work. This paper focuses on blockchain systems, smart contracts and architecture, smart contracts in the cloud, and the IoT environment. Furthermore, we tried to bridge design and implementation details for readers to understand the patterns that can replicate for cloud-based manufacturing systems.

你可以尝试使用大模型来生成摘要 立即生成

【Keywords】Smart contract; blockchain; cloud manufacturing; cloud computing

【发表时间】2022

【收录时间】2022-07-31

【文献类型】 综述

【DOI】 10.31577/cai2022134