Follow blockchain research across journals, conferences, and preprint repositories.
29,250 results · page 1146 of 1,219
Mohammad Jafarinejad, Hamid Sakaki
No abstract is available for this record.
Efe Akinci, Jing Li
This paper studies Granger Causality relations between Bitcoin and 5 stock market indexes which are Japan, Russia, South Korea, Sweden and the United States. The time-period examined is from 2013 to 2017 and all the tests are conducted based on daily data. We analyze this in three different periods, last 5 years (2013-2017), in 2017 and last 3 months of 2017. To estimate the relationship, we use unit root test and Augmented Dickey-Fuller, Lagrange Multiplier, Johansen Cointegration Test and finally Granger Causality Test. After the tests, countries have a same integrated order that exhibits a long-run relationship. In causality, except for Russia, each country has affected the Bitcoin prices and being affected in a different period, especially in the last 3 months of 2017, the impact and popularity of Bitcoin affect too much the stock market in the short-run. As a result, the causation between Bitcoin and stock market indexes shows impact statistically significant in the 2017 year. The importance of cryptocurrency and popularity not as much as hype like late 2017 in 2018, but we think that cryptocurrencies are one of the major currencies that affect economical world very deeply.
Alastair Berg, Chris Berg, Sinclair Davidson, Jason Potts
No abstract is available for this record.
Manuj Subhankar Sahoo, Pallav Kumar Baruah
After the introduction of Bitcoin, blockchain has made its way through numerous applications and been adopted by various communities. A number of implementations exist today providing a platform to carry on business with ease. However, it is observed the scalability of blockchain still remains an issue. Also, none of the framework can claim the ability to handle Big Data and support to perform analytics, which is an important and integral facet of current world of business. We propose HBasechainDB, a scalable blockchain-based tamper-proofed Big Data store for distributed computing. HBasechainDB adds the blockchain characteristics of immutability and decentralization to the HBase database in the Hadoop ecosystem. Linear scaling is achieved by pushing computation to the data nodes. HBasechainDB comes with inherent property of efficient big data processing as it is built on Hadoop ecosystem. HBasechainDB also makes adaptation of blockchain very easy for those organizations whose business logic are already existing on Hadoop ecosystem. HBasechainDB can be used as a tamper-proof, decentralized, distributed Big Data store.
Jamil Civitarese
No abstract is available for this record.
Yasar Kaya
In this paper, the price fluctuations of Bitcoin under speculative environment is studied. It has been seen that the market trend points out an existence of a speculative bubble. Over the course of the period from 2014 to 2018, the trend in price movements of bitcoin has proved to be strongly speculative. In that regard, investors might be curious about what drivers might be instrumental in these speculative price changes. After reviewing of NPV, it was seen that NPV is not applicable to the case of cryptocurrencies due to their nature and lack of free cash flows to base the asset valuation to some fundamental facts. Later, LPPL model is reviewed, however, that also proved to be insufficient since it does not reflect the investor speculations and inform much about price dynamics regarding behavioral finance principles. Then, some papers from the past price fluctuations of bitcoin (for the period from 2010 to 2013) was reviewed and three key variables were determined which might explain price movements. Public interest towards Bitcoin as interest-driven, regulatory and political news about cryptocurrencies as event-driven and VIX as overall investor approach to Bitcoin market have been taken. After running regressions, the only significant variable happened to be public interest and popularity of Bitcoin. Although, for some cases, VIX variable also explain price fluctuations for some intervals, in none of the cases event-driven variable has long- terms effect on price fluctuations under speculative environment. Lastly, a robustness test is also handled considering the âweekend effectâ and it has been seen public interest variable again proved to be a significant price determinant.
MichaĆ R. Hoffman, Luis Ibåñez, Huw Fryer, Elena Simperl
No abstract is available for this record.
Campbell R. Harvey, Christine Moorman, Marc Toledo
No abstract is available for this record.
Jianfu Wang
Distributed Ledger Technology (DLT) creates a decentralized system for trust and transaction validation using executable smart contracts to update information across a distributed database. This type of ecosystem can be applied to Commodity Trade Finance to alleviate critical issues of information asymmetry and the cost of transacting which are the leading causes of the Trade Finance Gap (ie. the lack of supply of capital to meet total trade finance demand). The possibility of scaling up such ecosystems with a number of Institutional Investors and micro small medium enterprises (MSME) would be advantageous, however, it brings up its own set of challenges including the stability of the system design. Agent-based modeling (ABM) is a powerful method to assess the financial ecosystem dynamics. DLT ecosystems model well under ABM, as the agents present a clearly defined taxonomy. In this study, we use ABM to assess the Aquifer Institute Platform - a DLT-based Commodity Trade Finance system, in which a growing number of participating parties is closely related to the circulation of utility tokens and transaction flows. We study the system dynamics of the platform and propose an appropriate setup for different transaction loads.
Yang Xu, Guojun Wang, Jidian Yang, Ju Ren · 6 authors
The emerging network computing technologies have significantly extended the abilities of the resourceâconstrained IoT devices through the networkâbased service sharing techniques. However, such a flexible and scalable service provisioning paradigm brings increased security risks to terminals due to the untrustworthy exogenous service codes loading from the open network. Many existing security approaches are unsuitable for IoT environments due to the high difficulty of maintenance or the dependencies upon extra resources like specific hardware. Fortunately, the rise of blockchain technology has facilitated the development of service sharing methods and, at the same time, it appears a viable solution to numerous security problems. In this paper, we propose a novel blockchainâbased secure service provisioning mechanism for protecting lightweight clients from insecure services in network computing scenarios. We introduce the blockchain to maintain all the validity states of the offâchain services and edge service providers for the IoT terminals to help them get rid of untrusted or discarded services through provider identification and service verification. In addition, we take advantage of smart contracts which can be triggered by the lightweight clients to help them check the validities of service providers and service codes according to the onâchain transactions, thereby reducing the direct overhead on the IoT devices. Moreover, the adoptions of the consortium blockchain and the proof of authority consensus mechanism also help to achieve a high throughput. The theoretical security analysis and evaluation results show that our approach helps the lightweight clients get rid of untrusted edge service providers and insecure services effectively with acceptable latency and affordable costs.
Roy Keidar, Sttphane Blemus
No abstract is available for this record.
Anton Kajtazi, Andrea Moro
No abstract is available for this record.
Maneesh Mishra, Rakesh Ranjan
India riding on its demographic advantage will account for more than half of the increase in Asiaâs workforce in the coming decade, but this isnât just a story of more workers. These new workers will have to be much better trained than the existing workforce. For India to reap the dividends of its demographic potential, there is an urgency to equip the youth with necessary skills. Though Skill India outlines this national priority, the outcomes of the public funded skill development efforts have witnessed variance in outcomes with quality being the key concern. Effective monitoring could potentially address many of these challenges but M&E of skill development programs in India suffers from weak data validation processes and lacks technology enablement. This working paper discusses the data requirement for effective monitoring and aims at initiating a dialogue on the case for Distrusted Ledger Technology (DLT) and blockchain enabled monitoring in the Indian Skill Development Ecosystem.
David Mendes, Irene Pimenta Rodrigues, César Fonseca, Manuel José Lopes · 6 authors
We introduce our solution developed for data privacy, and specifically for cognitive security that can be enforced and guaranteed using blockchain technology in SAAL (Smart Ambient Assisted Living) environments. Personal clinical and demographic information segments to various levels that assures that it can only be rebuilt at the interested and authorized parties and no profiling can be extracted from the blockchain itself. Using our proposal the access to a patient's clinical process resists tampering and ransomware attacks that have recently plagued the HIS (Hospital Information Systems) in various countries. The core of the blockchain model assures non-repudiation possible by any of the involved information producers thus maintaining ledger fidelity of the enclosed historical process information. One important side effect of this data infrastructure is that it can be accessed in open form, for research purposes for instance, since no individual re-identification or group profiling is possible by any means.
Christian Fisch
No abstract is available for this record.
Tuyet Duong
Cryptocurrencies like Bitcoin have proven to be a phenomenal success. The underlying techniques hold huge promise to change the future of financial transactions, and eventually the way people and companies compute, collaborate, and interact. At the same time, the current Bitcoin-like proof-of-work based blockchain systems are facing many challenges. In more detail, a huge amount of energy/electricity is needed for maintaining the Bitcoin blockchain. In addition, their security holds if the majority of the computing power is under the control of honest players. However, this assumption has been seriously challenged recently and Bitcoin-like systems will fail when this assumption is broken. This research proposes novel blockchain designs to address the challenges. We first propose a novel blockchain protocol, called 2-hop blockchain, by combining proof-of-work and proof-of-stake mechanisms. That said, even if the adversary controls more than 50% computing power, the honest players still have the chance to defend the blockchain via honest stake. Then we revise and implement the design to obtain a practical cryptocurrency system called Twinscoin. In more detail, we introduce a new strategy for difficulty adjustment in the hybrid blockchain and provide an analysis of it. We also show how to construct a light client for proof-of-stake cryptocurrencies and evaluate the proposal practically. We implement our new design. Our implementation uses a recent modular development framework for blockchains, called Scorex. It allows us to change only certain parts of an application leaving other codebase intact.
Ibrahim Shehata
No abstract is available for this record.
M. Todd Henderson, Max Raskin
No abstract is available for this record.
Ryan Clements
The purpose of this paper is to assess the evolution of cryptocurrency including its demand factors, latent value propositions and regulatory developments. The cryptocurrency market has experienced unprecedented growth driven by improved ease of access, speculation, familiarity, media attention, network effects, mining activity, distrust of traditional banking, global instability hedging, and a demand effect from the initial coin offering (ICO) market. This had led to wide asset bubble speculation. The future of cryptocurrency is impossible to predict, and although it is unlikely that cryptocurrency will eliminate trusted intermediaries, and replace sovereign fiat altogether, it has numerous latent value propositions and long-term use cases including distributed ledger technology (DLT) and blockchain innovations (particularly in financial payments, settlements, clearing, supply chain, agriculture, and voting), identity and data protection mechanisms, crowd-funding, and decentralized business applications and services.There may also be benefits to a bubble including âlong tailâ successes, hype-financed research and development in DLT and blockchain infrastructure (that wouldnât have otherwise received funding in a reticent market), and consumer familiarity benefits. The regulatory response to date has largely been enforcement based (emphasizing fraud detection and criminal deterrence), with public statements and interest across a diverse range of regulatory bodies, rather than unified rules. There are however inherent difficulties in regulating the cryptocurrency market, which will be discussed in detail in this paper.
Andrew Burnie, James Burnie, Andrew Henderson
The rise of cryptocurrency as a new sui generis asset class creates a need for a new classification scheme to cover the wide range of functionality for which tokens can be used. By differentiating tokens based on their functional attributes, cryptocurrency tokens can be categorised into crypto-transaction tokens (which act as a cash substitute); crypto-fuel tokens (which underpin generic blockchain applications); and crypto-voucher tokens (which can be exchanged for a predefined asset). This classification is applied to identify important issues when considering whether to participate in a cryptocurrency system, such as the impact of potential forks, token supply expectations and the level of dependence on a few operators (entity-dependence). For crypto-transaction tokens (and crypto-fuel tokens if used in a similar or overlapping role) it shows the importance of the token being seen as a âbetterâ form of money. For crypto-fuel tokens, the popularity of blockchain applications and the utility of the crypto-fuel system in application development is vital. For crypto-voucher tokens, the value of the underlying asset, the tokenâs exchangeability for that asset and the importance of a digital representation should be considered by participants. The interplay between fundamentals and speculation as drivers of price is considered.An erratum to this article has been published at as DOI: https://doi.org/10.5195/ledger.2018.151.
Peder Ăstbye
No abstract is available for this record.
ÎÏÎŹÎœÎœÎ·Ï ÎÎčÏαΟλ, Ioannis Michail
Throughout the history of mankind, trusted relationships have played a vital part in every \ntransaction humans have made. Those transactions belong to a spectrum that starts from \neveryday life decisions and acts, to a more complex, sensitive and wide area that even nations \nare involved. \nBefore the era of globalization of telecommunications that we live in, achieving trust was \nmore related to human relations. Even though that the meaning of trust is known to all, it is \nhard to find a definition that strictly describes it. \nTrust is multidimensional, multidisciplinary and multifaceted concept. Many definitions can \nbe found in literature and are related to notions as goodness, strength, reliability, integrity, \nability or character of a person or thing. A trust relationship involves two parties, a trustor \nand a trustee. The trustor is the person that holds confidence, belief on the reliability of \nanother person or thing which is the other party, the trustee. (Zheng & Valtteri Niemi, \nTowards User Driven Trust Modeling and Management, 2009) \nHow though trust is established in modern computer networks, where the notions of the \ntrustor and trustee are not represented by strictly humans, but from entities that might never \nhave had a relationship upon the trust can be build. \nIn this project we will study the achievement of trust in traditional kinds of networks such as \nad-hoc, mobile and wireless and we will examine the ability to elevate the trust level in a \ncomputer network using the under development and mostly promising blockchain network. \nThe network is going to be setup as a private blockchain network, where all the nodes that \nconsist it, will be pre-set from an administrative team. The computers that will participate will \nhave all the requirements in order to connect to the private network running as services on \nboot. \nThe application will run on each node and on starting the application the very first check will \nbe to start the node and connect to the network. Only if the network has been found and the \nnode is connected to it, the application proceeds with checking the presence of web3js and \nonly after successfully checking the communication of the web3js with the network, the user \nis prompt with the login page. \nThe authorization of the user is checked upon a smart contract on the blockchain network \nand after a successfully prompt from the smart contract, the credentials are checked, in our \ncase, on a fake backend where a JWT token is issued to the user in order to use the application \ndepending on the role that he has.
Jamil Civitarese
Metcalfe's Law argues the value of a network is proportional to the square of its users. Bitcoin and other cryptocurrencies can be modeled as such: if Metcalfe's Law is true, then it is possible to forecast prices using the size of the network. I test this assertion by a cointegration test between price and an adjusted number of wallets' connections. It is stated that the series do not cointegrate, rejecting the Metcalfe's Law. A first-differences model is employed to further analyse the relation between returns and variations in the number of wallets. It is stated that Metcalfe's Law consistently predicts the trend in the value of Bitcoin; nevertheless, it is not possible to reject the reverse causation of Bitcoin returns leading to new wallets.
Margaret Ryznar
Bitcoin emerged as a cryptocurrency relying on new blockchain technology in 2009, but how to regulate it was not immediately clear. The recent emergence of bitcoin futures poses a new level of risk to the economy, again raising questions of regulation. This is the first law review article to examine the potential regulatory regime for bitcoin futures.