Follow blockchain research across journals, conferences, and preprint repositories.
51,074 results · page 1950 of 2,129
Ebru Gökalp, Mert Onuralp Gökalp, Selin Ăoban, P. Erhan Eren
No abstract is available for this record.
Ivar Bengtsson, Michael Fichter
This paper is an attempt to analyze the role of transaction fees in a proof-of-stake cryptocurrency currently in development. The authors have employed a microeconomic, static equilibrium approach to model a market in which the cryptocurrency is exchanged for a physical good. Furthermore, the relationship between transaction capacity and the size of the network has been investigated. It has been shown that the total amount of validator capital and the number of validators can be controlled by setting a fixed fee on transactions as well as a minimum capital requirement on individual validators. The total surplus in the economy has then been optimized by setting a fee and the authors have discussed how a minimal capital requirement could be used to also optimize transaction capacity.
Sina Rafati Niya, Florian SchĂŒpfer, Thomas Bocek, Burkhard Stiller
Abstract This work introduces the design and implementation of an Android-based Peer-to-peer Purchase and Rental Application termed PuRSCA, which leverages Smart Contracts (SC) and the Ethereum public blockchain (BC). As a Device-to-device (D2D) communication protocol, WiFi-Direct is chosen to enable the P2P data transmission between two parties. This work results in a cost-efficient, secure, SC-based, P2P, and Decentralized application (Dapp). Evaluations on performance of this Dapp is specified in terms of its D2D deployment, transaction costs, scalability, security, and privacy.
Shaun Azzopardi, Gordon J. Pace, Fernando Schapachnik
Smart contracts have been proposed as executable implementations enforcing real-life contracts. Unfortunately, the semantic gap between these allows for the smart contract to diverge from its intended deontic behaviour. In this paper we show how a deontic contract can be used for real-time monitoring of smart contracts specifically and request-based interactive systems in general, allowing for the identification of any violations. The deontic logic of actions we present takes into account the possibility of action failure (which we can observe in smart contracts), allowing us to consider novel monitorable semantics for deontic norms. For example, taking a rights-based view of permissions allows us to detect the violation of a permission when a permitted action is not allowed to succeed. A case study is presented showing this approach in action for Ethereum smart contracts.
Paraskevi Katsiampa, ÎÏÎœÏÏαΜÏÎŻÎœÎżÏ ÎÎșίλλαÏ, François Longin
No abstract is available for this record.
Sheila Ainon Yussof, Abdullah AlâHarthy
Fintech (or financial technology) is the current driving force behind innovations in the financial services industry. One of the most debated innovations is cryptocurrency, or digital currency, which uses blockchain technology to make a direct electronic payment between two people possible, without going through a third party (like a bank) or expensive intermediaries in order to save costs. This future money is pressurising central banks to manage the looming threat of redundancy as it overshadows fiat currency in a world of infinite fintech possibilities. Bitcoin, being the first decentralised cryptocurrency, will be the focus of this research. This digital currency is not produced by minting money in an unlimited supply, but through a virtual mining process designed to control the supply of money and make it more valuable. The increasing pace in financial innovation is pushing regulators to make a change in the way they define money and what money can be. Traditionally money is used to serve as a medium of exchange, legal tender for repayment of debt, standard of value, unit of accounting measure and a means to save or store purchasing power. Bitcoin may not fulfill all the functions of money but its scarcity value, anonymity (or pseudonymity), transparency, and autonomy from the government, make it attractive to users who are speculators, traders, merchants, consumers and netizens disenchanted with fiat money. Despite the alluring features of Bitcoin, it is not spared from potential abuses such as webcrimes, tax evasion, fraud, online black markets, money laundering and terrorism financing. In this paper, a forensic examination of Bitcoins benefits and risks will help regulators decide whether to adopt cryptocurrency and provide an appropriate framework to regulate it based on other jurisdictions approach. This paper recommends that Malaysia should fully embrace cryptocurrency due to global trends - the Islamic Development Bank is developing Shariah compliant contracts using blockchain technology; China is leading the drive to develop its own national cryptocurrency to complement fiat money; and a Shariah-compliant cryptocurrency has already entered the market backed by gold (Onegram). Financial and regulatory architectures in Malaysia should accommodate these changes to remain relevant. In addition, future research is recommended focusing on developing a Shariah compliant national cryptocurrency that is unique to Malaysia.
Wee Seng Wong, Dennis Saerbeck, Dante Delgado Silva
No abstract is available for this record.
Rebecca M. Bratspies
No abstract is available for this record.
David Fox
Abstract This chapter focuses on the characterisation and treatment of cryptocurrencies in the common law of property, using Bitcoin as the main example. It first examines how a crypto-coin might be viewed as an object of property, and more specifically whether it could make a suitable object for any regime of property rights at all, before discussing the fungibility, specificity, scarcity and exclusivity of cryptocurrencies in the context of property law. It then considers whether crypto-coins fall into either of the two conventionally recognised categories of personal property: choses in possession or choses in action. It also explores the applicability of rules of derivative transfer of title to crypto-coin transactions, and how the standard rules of following and tracing may be used for the identification and tracing of cryptocurrencies through mixtures. Finally, it looks at remedies available at common law and in equity for enforcing titles to cryptocurrencies.
JT Hamrick, Farhang Rouhi, Arghya Mukherjee, Amir Feder · 7 authors
The surge of interest in cryptocurrencies has been accompanied by a proliferation of fraud. This paper examines a pervasive tactic long known to financial markets: pump and dump schemes. While the fundamentals of the ruse have not changed in the last century, the recent explosion of nearly 2, 000 cryptocurrencies in a largely unregulated environment has greatly expanded the scope for abuse. The paper first quantifies the scope of cryptocurrency pump and dump on Discord and Telegram, two widely popular group messaging platforms with 130 million users and 200 million users respectively. Both platforms can handle large groups with thousands of users, and they are the most popular outlets for pump and dump schemes involving cryptocurrencies. We identified 3, 767 different pump signals advertised on Telegram and another 1, 051 different pump signals advertised on Discord during a six-month period in 2018. The schemes promoted more than 300 cryptocurrencies. These comprehensive data provide the first measure of the scope of pump and dump schemes across cryptocurrencies and suggest that this phenomenon is widespread and often quite profitable. This should raise concerns among regulators. We then examine which factors that affect the "success" of the pump, as measured by the percentage increase in price near the pump signal. We find that the coin's rank (market capitalization/volume) is the most important factor in determining the profitability of the pump: pumping obscure coins (with low volume) is much more profitable than pumping the dominant coins in the ecosystem.
Shaen Corbet, Charles Larkin, Brian M. Lucey, Andrew Meegan · 5 authors
No abstract is available for this record.
Pierluigi Martino, Kevin Jue Wang, Cristiano Bellavitis, Carlos M. DaSilva
Blockchain is a revolutionary technology that allows people to record transactions on a digital, decentralized, distributed ledger, without any central authority. Some consider this technology as âthe trust machineâ and cryptocurrency is without doubt the most notable by-product of the blockchain revolution. Initial coin offering (ICO) is a new way to raise entrepreneurial finance, newly created cryptocurrencies are being sold to the public by start-ups in exchange of capital. This chapter intends to clarify this phenomenon by explaining the concepts of blockchain technology, cryptocurrency and ICO, in order to provide valuable insights into this new trend of entrepreneurial finance.
Keaton Brown
With the explosive growth in cryptocurrencies over the last couple of years, the cost of mining these technologies (the process through which users devote CPU power to operate the underlying blockchains) have similarly exploded. This paper examines one overarching question regarding this issue ù what factor or factors explain the geographic distribution of cryptocurrency nodes (mining operations) across the world? In exploring this question, this research considers electricity price, internet access, Tor network relays, and others. Using node distribution data for Bitcoin and Ethereum ù the two largest cryptocurrencies ù this paper analyzes cross-sectional and panel data regression models, and establishes that electricity price has not played a significant role in this distribution up to this point, and concludes that the historical association between Tor relays and Bitcoin use has had a much greater impact. Lastly, this paper discusses the broader implications of its findings, and the potential areas of research for further understanding of this field.
ChulâJin Kim
No abstract is available for this record.
Cathy YiâHsuan Chen, Wolfgang Karl HĂ€rdle, Ai Jun Hou, Ning Wang
The CRIX (CRyptocurrency IndeX) has been constructed based on a number of cryptos and provides a high coverage of market liquidity, hu.berlin/crix. The crypto currency market is a new asset market and attracts a lot of investors recently. Surprisingly a market for contingent claims hat not been built up yet. A reason is certainly the lack of pricing tools that are based on solid financial econometric tools. Here a first step towards pricing of derivatives of this new asset class is presented. After a careful econometric pre-analysis we motivate an affine jump diffusion model, i.e., the SVCJ (Stochastic Volatility with Correlated Jumps) model. We calibrate SVCJ by MCMC and obtain interpretable jump processes and then via simulation price options. The jumps present in the cryptocurrency fluctutations are an essential component. Concrete examples are given to establish an OCRIX exchange platform trading options on CRIX.
Wei Zhang, Pengfei Wang, Xiao Li, Dehua Shen
We investigate the crossâcorrelations of returnâvolume relationship of the Bitcoin market. In particular, we select eight exchange rates whose trading volume accounts for more than 98% market shares to synthesize Bitcoin indexes. The empirical results based on multifractal detrended crossâcorrelation analysis (MFâDCCA) reveal that (1) the nonlinear dependencies and powerâlaw crossâcorrelations in returnâvolume relationship are found; (2) all crossâcorrelations are multifractal, and there are antipersistent behaviors of crossâcorrelation for q = 2; (3) the price of small fluctuations is more persistent than that of the volume, while the volume of larger fluctuations is more antipersistent; and (4) the rolling window method shows that the crossâcorrelations of returnâvolume are antipersistent in the entire sample period.
Frode KjĂŠrland, Maria Meland, Are Oust, Vilde Ăyen
The purpose of this study is to uncover factors that explain Bitcoin's price fluctuations. The price of the cryptocurrency Bitcoin is volatile and has increased from zero in 2009 to more than 19500 USD in December 2017. To explain the price movements we have estimated two autoregressive distributed lag models by using ordinary least squares regression. The data includes 279 weekly observations from 18.09.2011 to 05.02.2017 (before the extreme development from the summer of 2017). The dependent variable is the Bitcoin price and the analysis has examined nine independent variables. Our main finding and contribution is that political incidents and statements (âshocksâ) are significant drivers of Bitcoin's price. Moreover, the volume of Bitcoin and Bitcoin's price has a significant, negative relationship. The interest of Bitcoin, measured by Google searches, has a positive, significant relationship with Bitcoin's price. The study does not find evidence for Bitcoin being a safe haven investment.
Chris Berg, Sinclair Davidson, Jason Potts
No abstract is available for this record.
Patrick Li, Scott D. Nelson, Bradley Malin, You Chen
Background: Access to accurate and complete medication histories across healthcare institutions enables effective patient care. Histories across healthcare institutions currently rely on centralized systems for sharing medication data. However, there is a lack of efficient mechanisms to ensure that medication histories transferred from one institution to another are accurate, secure, and trustworthy. Methods: In this article, we introduce a decentralized medication management system (DMMS) that leverages the advantages of blockchain to manage medication histories. DMMS is realized as a decentralized network under the hyperledger fabric framework. Based on the network, we designed an architecture, within which each prescriber can create prescriptions for each patient and perform queries about historical prescriptions accordingly. Finally, we analyzed the advantages of DMMS over centralized systems in terms of accuracy, security, trustworthiness, and privacy. Results: We developed a proof of concept to showcase DMMS. In this system, a prescriber prescribes medications for a patient and then encrypts the prescriptions via the patientâs public keys. Patients can query their own prescriptions from different histories across healthcare institutions and then decrypt the prescriptions via their private keys. At the same time, a prescriber can query a patientâs prescription records across healthcare institutions after approval from the patient. Analytic results show that DMMS can improve security, trustworthiness, and privacy in medication history sharing and exchanging across healthcare institutions. In addition, we discuss the potential for DMMS in e-prescribing markets. Conclusions: This study shows that a distributed secure ledger can enable reliable, interoperable, and accurate medication history sharing. Keywords: Blockchain Ledger, Decentralized, Hyperledger Fabric Framework, Medication Histories Please see a related Letter to the Editor (https://doi.org/10.30953/bhty.v2.98), and its response (https://doi.org/10.30953/bhty.v2.108)
Shaimaa Badr, Ibrahim Gomaa, Emad Abd-Elrahman
Recently, Blockchain is considered as one of the main powerful techniques in security and privacy domains. It is considered as the promised security concept for replacing the current third parities trusting solutions. This could be achieved by mixing some cryptography techniques, consensus algorithms alongside with some peer-to-peer communication protocols. In this paper, to meet the requirement of distributed structure in the eHealth Records (EHRs) system, we propose a novel protocol to achieve a perfect privacy preserving for the patient namely Pseudonym Based Encryption with Different Authorities (PBE-DA) by applying the concept of Blockchain on the healthcare communication entities in an e-health platform. Therefore, PBE-DA will be used to help the patient anonymously to access, check or update his sensitive data on EHRs system. Moreover, we analyzed not only the public blockchain tier between the different EHRs cloud provider but also another Blockchain tier between the patient sensors (IoT devices used to do some patient measurements) and the patient system as a gateway for the whole healthcare platform.
Zhenghui Li, Hao Dong, Zhehao Huang, Pierre Failler
The rapid development of VFAs allows investors to diversify their choices of investment products. In this paper, we measure the return risk of VFAs based on GARCH-type model. By establishing a Markov regime-switching Regression (MSR) Model, we explore the asymmetric effects of speculation, investor attention, and market interoperability on return risks in different risk regimes of VFAs. The results show that the influences of speculation and investor attention on the risks of VFAs are significantly positive at all regimes, while market interoperability only admits a positive impact on risk under high risk regime. All of the three factors exert asymmetric effects on risks in different regimes. Further study presents that the risk regime-switching also shows asymmetric characteristic but the medium risk regime is more stable than any others. Therefore, transactions of investors and arbitrageurs are monitored by certain policies, such as limiting the number of transactions or restricting the trading amount at high risk regime. However, when return risk is low, it will return to a medium level if we encourage investors to access.
Guglielmo Maria Caporale, Alex Plastun, Viktor Oliinyk
This paper investigates the role of the frequency of price overreactions in the cryptocurrency market in the case of BitCoin over the period 2013â2018. Specifically, it uses a static approach to detect overreactions and then carries out hypothesis testing by means of a variety of statistical methods (both parametric and non-parametric) including ADF tests, Granger causality tests, correlation analysis, regression analysis with dummy variables, ARIMA and ARMAX models, neural net models, and VAR models. Specifically, the hypotheses tested are whether or not the frequency of overreactions (i) is informative about Bitcoin price movements (H1) and (ii) exhibits no seasonality (H2). On the whole, the results suggest that it can provide useful information to predict price dynamics in the cryptocurrency market and for designing trading strategies (H1 cannot be rejected), whilst there is no evidence of seasonality (H2 cannot be rejected).
Emilien Bai, KĂ„re Synnes
This paper discusses supporting collaborative care of elderly through a reward system based on distributed ledger technologies. The design and implementation of such a reward system that connect elderly and volunteers by mutual agreements involve technologies such as smart contracts and blockchains. The work is motivated by the demographic change, where an aging population consequently increases the need for care. This causes a great tension in our society, as care resources become increasingly constrained, both regarding costs and availability of care staff. Much of the daily care of the elderly is today done by family members (spouses, children) and friends, often on a voluntarily basis, which adds to the tension. The core idea of this work is to help broaden the involvement of people in caring for our elderly, enabled by a system for collaborative care. The proposed system benefits from recent advances in distributed ledger technologies, which similarly to digital currencies, are build on the ability for mutual agreements between people who do not know each other. The system also benefits from recent gamification techniques to motivate people to collaborate on a larger scale through performing simple daily tasks. The proposed system benefits from inherent distributed ledger technologies advantages, such as a high level of decentralization, thus a high availability, and strong data consistency. These advantages make it interesting to develop the possible links between blockchains and the outside world to allow for a higher level of automation and distribution of services such as collaborative care. New models for distributed ledger technologies, such as Iota tangles or the Swirld platform, may however scale and perform better than blockchains. These should thus be considered for a full implementation and test of the system. In summary, this paper presents a novel framework and prototype implementation of a reward system supporting collaborative care of elderly, that is based on distributed ledger technologies.
Youness Tribis, Abdelali El Bouchti, Houssine Bouayad
Groundbreakingly, blockchain technology (BCT) has gained widespread acceptance and importance in the last few years. Implemented in different areas of applications such as social and legal industries, finance, smart property, and supply chain networks. This technology assures immutability and integrity of data without the need of a third trusted party. Furthermore, BCT could guarantee a transparent and decentralized transaction system in businesses and industries. Even though general research has been done in the BCT, however, there is a lack of systematic analysis on current research challenges regarding how BCT is effectively applicable in supply chain management (SCM). A systematic literature review (SLR) of SCM based on blockchain does not exist yet. This work aims to explore and analyse the state-ofthe-art on the BCT applications for SCM. We synthesize existing evidence, and identify gaps, available in the literature. The survey uses a systematic mapping study (SMS) method to examine 40 extracted primary studies from scientific databases.