L. Horoshkova, Ievgen Khlobystov, Victoriya Trofymchuk
In work is proved, that it is impossible to ensure sustainability development of the state without creation of conditions of sustainability development of administrative - territorial units on the basis of model, which components is to economic, social and ecological structure by. The proved necessity of a concentration of attention on an ecological component. Is shown, that one of major ecological-economic tools of nature protection activity in Ukraine are the ecological tax and tax for pollution of an environment. By results of the analysis of dynamics of the tax for pollution of an environment is established, that last years the volumes of emissions of polluting substances have decreased. Is established, that the increase of volumes of the ecological tax in the incomes of the local budgets in 2015 is connected to the beginning of decentralization and brought in changes in the Tax code. Is proved, that the delay of rates of growth of receipt of the ecological tax in the local budgets is by a consequence of inefficient system of filling of the budgets of the incorporated territorial communities (ITC) and local budgets. The estimation a level of development of the economic mechanism of regulation and stimulation rational nature usage is carried out on the basis of parameters of nature protection financing. The analysis of dynamics of change of volumes of the charges on protection of an environment is carried out. Is established, that the charges of the budget of Ukraine grow by protection of environmental natural environment annually, but rates of this growth reduce meaning by the inflationary factors. Is established, that there is a delay of rates of financing from the state budget with simultaneous increase of financing from the local budgets. It has given the bases to assert, that created IТC more is weighed concern to ecological politics and necessity of financing of nature protection measures. The interrelation between receipt of the ecological tax in the budgets and dynamics of the charges on nature protection measures is investigated. Is established, that dynamics of receipt of the ecological tax in the budget does not coincide with dynamics of the charges of the budget on protection of an environment. It testifies to imperfection regulating mechanisms of ecological politics, both on the equal states, and at a level of separate territories. The necessity of development of the methodological approaches to a substantiation of effective directions of realization of state politics in sphere of protection an environment at a level IТC, recommendations for their scientific support, development of a complex of measures on their introduction and improvement of working organization-legal base is proved. The analysis of dynamics both sources financing of the capital and current investments in protection of an environment is carried out. Is shown, that dynamics of rates of growth of the capital investments is astable, owing to what there are no cardinal changes of an ecological situation in the country. Is shown, that the rates of growth of the current investments are insignificant, at a level of an official rate of inflation, which reduces their economic efficiency. The analysis of structure of sources financing of the capital and current investments in nature protection activity is carried out. The received results have confirmed the made conclusions concerning an inefficiency of state politics of realization of the capital investments in nature protection measures.
Boris Radovanov, Aleksandra Marcikić, Nebojša Gvozdenović
Because of increasing interest in cryptocurrency investments, there is a need to quantify their variation over time. Therefore, in this paper we try to answer a few important questions related to a time series of cryptocurrencies. According to our goals and due to market capitalization, here we discuss the daily market price data of four major cryptocurrencies: Bitcoin (BTC), Ethereum (ETH), Ripple (XRP) and Litecoin (LTC). In the first phase, we characterize the daily returns of exchange rates versus the U.S. Dollar by assessing the main statistical properties of them. In many ways, the interpretation of these results could be a crucial point in the investment decision making process. In the following phase, we apply an autocorrelation function in order to find repeating patterns or a random walk of daily returns. Also, the lack of literature on the comparison of cryptocurrency price movements refers to the correlation analysis between the aforementioned data series. These findings are an appropriate base for portfolio management. Finally, the paper conducts an analysis of volatility using dynamic volatility models such as GARCH, GJR and EGARCH. The results confirm that volatility is persistent over time and the asymmetry of volatility is small for daily returns.
Luís Picciochi Oliveira, Liudmila Zavolokina, Ingrid Bauer, Gerhard Schwabe
The growing usage of tokens in real-world blockchain projects – mostly visible in ICOs – has unveiled the need to understand what blockchain tokens in fact represent and how they relate to their underlying business model. Previous research has contributed to this gap but often lacks a comprehensive understanding of tokens and their design as well as of the growing and rapidly-changing complexity in token landscape. This has crucial implications for assessing tokens' value and utility. Applying a structured, scientific approach towards blockchain tokens, we provide a comprehensive token classification and a decision-aid on token design. This is based on a literature review and an empirical study to cover this research gap. Our work offers a novel contribution in an emerging field within the Blockchain research domain and proposes structured analytical tools which can be used by both practitioners and researchers.
The narrative of a Bitcoin is a bubble is very common. We employ statistical techniques to empirically evaluate such claim. A branch of literature links the existence of a bubble in some financial asset’s price to strict local martingales — a finitely lived asset has a bubble if, and only if, it is a strict local martingale under the equivalent risk-neutral measure. A diffusion process is a strict local martingale if its volatility increases faster than linearly as its level grows. We apply a nonparametric method to estimate the volatility function of Bitcoin daily and high frequency prices, as well as of more traditional financial assets. We then estimate the stochastic volatility model of Andersen and Piterbarg (2007), whose parameter space has a specific subset under which the asset’s price is a strict local martingale. Results suggest the existence of a bubble in Bitcoin prices from early 2013 to mid 2014, but, interestingly, not in late 2017.
Andrey A. Gusev, 49 Leningradsky Prospect, Moscow, 125993, Russia
Many fintech start-ups participant companies and cryptocurrencies have experienced phenomenal growth in value during the past several years.Many specialists would like to know the reasons for such success.In this article we investigate the predictive power of public opinions.This is one of the few works that using quantitative analysis connects social media and internet users' activities with cryptocurrency valuations.
Session Description: Privacy laws like GDPR and California Consumer Privacy Act (CCPA) have created a much more regulated environment in which enterprises need to operate in regards to consumer data permissions. Built on hyperledger fabric, HealthVerity Consent is an enterprise-level platform that allows organizations to aggregate and manage all existing touchpoints across the organization in one central location to comply with evolving privacy requirements. In this session we'll review what it took to deliver an enterprise blockchain installation where we drove business process change across departments and companies to better manage rights to data access and use. We’ll cover: • 5 key lessons learned you can apply to future blockchain implementations • How to integrate into a non-blockchain ecosystem • What challenges were faced in order to drive business process change with blockchain • How to manage existing barriers when migrating from legacy systems and business process to distributed ledger technology
A.V. Bogucharskov, I.E. Pokamestov, Karine Adamova, Zh. N. Tropina
The complexity of trade finance instruments associated with need for many accompanying documents, constant coordination are problems of this process.Successful development of trade finance instruments depend on improvement of software and implement blockchain solutions that enable companies to unite and through partnerships and process automation to accelerate cash flow and documentation throughout supply chain.The paper aims to examine areas and ways of blockchain application in trade finance and to identify key aspects of improving transactions process.We present possible interaction of participants with digital letters of credit and factoring with blockchain application and display its effect on key trade finance instruments.Moreover, we identifies a number of problems, implementation solutions of which will lead to further more efficient application of technology in supply chain finance.The achieving these goals will lead to further more effective application of blockchain in financing of supply chain.Blockchain with a high level of functionality and security in trade finance processes reduces processing time for documents, transaction costs, expanding number of participants and increases level of transparency.
Abstract It has been more than 10 years since Satoshi Nakamoto published his famous paper entitled ‘Bitcoin: a peer-to-peer electronic cash system’, which set the foundation of blockchain technology. Accompanied by the price volatility of bitcoins from 2017 to 2018, blockchain has been a hot word on the internet, and particularly hot in China. Blockchain offers a distributed and secure system for data storage and value transactions. Its applications are springing up in multiple fields. The Chinese government is considering these trends with great caution. Initial coin offering has been banned in China since September 2017. By contrast, an official white paper on China's blockchain technology, which was released in May 2018, said that blockchain technology will be widely applied in the real economy of China within 3 years. In a recent panel discussion held by National Science Review, experts talked about related topics. Their opinions may provide a quick view of the future development of blockchain in China and abroad. Jing Chen Assistant Professor of Computer Science Department, Stony Brook University and Chief Scientist at Algorand LLC, USA Xiaotie Deng Professor of School of Electronics Engineering and Computer Science, Peking University, China Guohua Gan Vice President of Beijing Tai Cloud Technology Corp., China Xiaoyun Wang Professor of Institute of Advanced Study, Tsinghua University, China Zhiming Zheng Professor of School of Mathematics and Systems Science, Beihang University, China Lei Guo (Chair) Professor of Academy of Mathematics and Systems Science, Chinese Academy of Sciences, China
Bing Jia, Tao Zhou, Wuyungerile Li, Zhenchang Liu · 5 authors
Crowd sensing is a perception mode that recruits mobile device users to complete tasks such as data collection and cloud computing. For the cloud computing platform, crowd sensing can not only enable users to collaborate to complete large-scale awareness tasks but also provide users for types, social attributes, and other information for the cloud platform. In order to improve the effectiveness of crowd sensing, many incentive mechanisms have been proposed. Common incentives are monetary reward, entertainment & gamification, social relation, and virtual credit. However, there are rare incentives based on privacy protection basically. In this paper, we proposed a mixed incentive mechanism which combined privacy protection and virtual credit called a blockchain-based location privacy protection incentive mechanism in crowd sensing networks. Its network structure can be divided into three parts which are intelligence crowd sensing networks, confusion mechanism, and blockchain. We conducted the experiments in the campus environment and the results shows that the incentive mechanism proposed in this paper has the efficacious effect in stimulating user participation.
С. В. Криворучко, Владислав Понаморенко, Anatoly Nebera
: Private cryptocurrencies became an integral part of the financial market. Central banks expressed various positions with respect to cryptocurrency from strong denial to non-intervention. We found out a common and dominating trend in the central bank’s policy to lead the further development of crypto-currency by restrictions, robust surveillance and licensing. The first section contains common information about central banks’s approach to regulation cryprocurrencies. Next section summarizes the treatment of cryptocurrency by central bankers, also it cointains 2 tables devoted to typology of cryptocurrency legality by countries and recognition of cryptocurrency by countries. Section 3 is devoted to the impact of global crisis on the dissemination of digital cryptocurrencies and contains 5 tables with information about banknotes and coins in circulation and a tables with top-10 cryptocurrencies. Section 4 describes the typology of warning signals sent by central banks to general public, investors, and market players. Section 5 concludes the material.
Over the past 30 years financial markets have moved from a highly centralized to a globalized system that includes all the world's stock exchanges and other financial institutions. The global stock architecture has united the world market. Traditionally, trading in financial instruments took place between stock brokers and traders who made personal transactions on trading platforms. At that time, stock brokers were monopolists of the market, only their information, their recommendations were the only source of information for investors. This was before the dotcom revolution, when communication became simple and accessible to everyone. Trade has been transformed from physical to electronic form, today you can buy securities, currencies and any derivatives in any quantity, at any time and from anywhere in the world. Development of blockchain technologies is integrated into financial transactions. Financial intermediaries are forced to follow the market and actively introduce new technologies in their processes. This article will consider the possibility of using the technology of the distributed ledger by institutions of custodian infrastructure. Today, a number of Russian financial institutions are developing their own projects using blockchain.
Summary Decentralization, in the form of mesh networking and blockchain, two promising technologies, is coming to the telecommunications industry. Mesh networking allows wider low‐cost Internet access with infrastructures built from routers contributed by diverse owners, whereas blockchain enables transparency and accountability for investments, revenue, or other forms of economic compensations from sharing of network traffic, content, and services. Crowdsourcing network coverage, combined with crowdfunding costs, can create economically sustainable yet decentralized Internet access. This means that every participant can invest in resources and pay or be paid for usage to recover the costs of network devices and maintenance. While mesh networks and mesh routing protocols enable self‐organized networks that expand organically, cryptocurrencies and smart contracts enable the economic coordination among network providers and consumers. We explore and evaluate two existing blockchain software stacks, Hyperledger Fabric (HLF) and Ethereum geth with Proof of Authority (PoA) intended as a local lightweight distributed ledger, deployed in a real city‐wide production mesh network and in laboratory network. We quantify the performance and bottlenecks and identify the current limitations and opportunities for improvement to serve locally the needs of wireless mesh networks, without the privacy and economic cost of relying on public blockchains.
Zijian Bao, Bin Wang, Yongxin Zhang, Qinghao Wang · 5 authors
We propose Lockcoin, a secure and privacy-preserving mix service for bitcoin anonymity. We introduce mix servers to provide mix service for user to prevent attackers linking the input address with output address by using blind signature shceme, multisignature scheme. Lockcoin provides anonymity, scalability, bitcoin compatibillity, theft impossibility and accountability. We have proposed a prototype of Lockcoin based on bitcoin test network, experimental results show that our solution is efficient. Lockcoin's source codes are released on github.com/Northeastern-University-Blockchain/Lockcoin.
The blockchain technology has potential applications in various areas such as smart-contracts, Internet of Things (IoT), land registry, supply chain management, storing medical data, and identity management. Although the Github currently hosts more than six thousand active Blockchain software (BCS) projects, few software engineering research has investigated these projects and its' contributors. Although the number of BCS projects is growing rapidly, the motivations, challenges, and needs of BCS developers remain a puzzle. Therefore, the primary objective of this study is to understand the motivations, challenges, and needs of BCS developers and analyze the differences between BCS and non-BCS development. On this goal, we sent an online survey to 1,604 active BCS developers identified via mining the Github repositories of 145 popular BCS projects. The survey received 156 responses that met our criteria for analysis. The results suggest that the majority of the BCS developers are experienced in non-BCS development and are primarily motivated by the ideology of creating a decentralized financial system. Although most of the BCS projects are Open Source Software (OSS) projects by nature, more than 93% of our respondents found BCS development somewhat different from a non-BCS development as BCS projects have higher emphasis on security and reliability than most of the non-BCS projects. Other differences include: higher costs of defects, decentralized and hostile environment, technological complexity, and difficulty in upgrading the software after release. Software development tools that are tuned for non-BCS development are inadequate for BCS and the ecosystem needs an array of new or improved tools, such as: customized IDE for BCS development tasks, debuggers for smart-contracts, testing support, easily deployable simulators, and BCS domain specific design notations.
Nathaniel Mason, Charles O. Oyaya, Julia Boulenouar
Abstract Motivation Across the Global South, unclear institutional frameworks undermine progress in improving services. Often, ongoing decentralization reforms reduce clarity further. Policy professionals working on institutional reform lack comparative models. Purpose To identify key challenges for the institutional arrangements for urban sanitation in decentralizing contexts, in Kenya and elsewhere, and to propose possible responses. Approach and methods We use key informant interviews and literature review in a problem‐driven analysis, drawing from three comparative case studies: South Africa, Indonesia and Tamil Nadu State. The analysis builds upon research on institutional effectiveness—co‐operation, collaboration and co‐ordination—rooted in game theory and elaborated in the 2017 World Development Report. Findings Three key problems in Kenya are identified: overlaps and competition around sector leadership at national and devolved levels; weak incentives for county governments to commit policy attention and finance, despite devolution; and limited regulatory oversight. Policy implications We identify a range of options for urban sanitation policy‐makers: (a) to engage non‐sectoral authorities in co‐ordinating multi‐sectoral issues across all levels of government; (b) to encourage political commitment to pro‐poor sanitation services at decentralized levels; and (c) to use incentive‐based and risk‐based approaches to regulate decentralized entities and strengthen local capacity for monitoring and enforcement.
Jianbo Gao, Han Liu, Chao Liu, Qingshan Li · 6 authors
While Ethereum smart contracts enabled a wide range of blockchain applications, they are extremely vulnerable to different forms of security attacks. Due to the fact that transactions to smart contracts commonly involve cryptocurrency transfer, any successful attacks can lead to money loss or even financial disorder. In this paper, we focus on the overflow attacks in Ethereum, mainly because they widely rooted in many smart contracts and comparatively easy to exploit. We have developed EASYFLOW, an overflow detector at Ethereum Virtual Machine level. The key insight behind EASYFLOW is a taint analysis based tracking technique to analyze the propagation of involved taints. Specifically, EASYFLOW can not only divide smart contracts into safe contracts, manifested overflows, well-protected overflows and potential overflows, but also automatically generate transactions to trigger potential overflows. In our preliminary evaluation, EASYFLOW managed to find potentially vulnerable Ethereum contracts with little runtime overhead. A demo video of EASYFLOW is at https://youtu.be/QbUJkQI0L6o.
Some of the recent blockchain proposals, such as Stellar and Ripple, use quorum-like structures typical for Byzantine consensus while allowing for open membership. This is achieved by constructing quorums in a decentralised way: each participant independently chooses whom to trust, and quorums arise from these individual decisions. Unfortunately, the theoretical foundations underlying such blockchains have not been thoroughly investigated. To close this gap, in this paper we study decentralised quorum construction by means of federated Byzantine quorum systems, used by Stellar. We rigorously prove the correctness of basic broadcast abstractions over federated quorum systems and establish their relationship to the classical Byzantine quorum systems. In particular, we prove correctness in the realistic setting where Byzantine nodes may lie about their trust choices. We show that this setting leads to a novel variant of Byzantine quorum systems where different nodes may have different understanding of what constitutes a quorum.
One major shortcoming of permissionless blockchains such as Bitcoin and Ethereum is that they are unsuitable for running Computationally Intensive smart Contracts (CICs). This prevents such blockchains from running Machine Learning algorithms, Zero-Knowledge proofs, etc. which may need non-trivial computation. In this paper, we present YODA, which is to the best of our knowledge the first solution for efficient computation of CICs in permissionless blockchains with guarantees for a threat model with both Byzantine and selfish nodes. YODA selects one or more execution sets (ES) via Sortition to execute a particular CIC off-chain. One key innovation is the MultI-Round Adaptive Consensus using Likelihood Estimation (MIRACLE) algorithm based on sequential hypothesis testing. M I RACLE allows the execution sets to be small thus making YODA efficient while ensuring correct CIC execution with high probability. It adapts the number of ES sets automatically depending on the concentration of Byzantine nodes in the system and is optimal in terms of the expected number of ES sets used in certain scenarios. Through a suite of economic incentives and technical mechanisms such as the novel Randomness Inserted Contract Execution (RICE) algorithm, we force selfish nodes to behave honestly. We also prove that the honest behavior of selfish nodes is an approximate Nash Equilibrium. We present the system design and details of YODA and prove the security properties of MIRACLE and RICE. Our prototype implementation built on top of Ethereum demonstrates the ability of YODA to run CICs with orders of magnitude higher gas per unit time as well as total gas requirements than Ethereum currently supports. It also demonstrates the low overheads of RICE.
Introduction. Bitcoin is a digital, decentralized, partially anonymous currency, not supported by any government or legal entity and not provided with gold or other goods. It relies on a peer-to-peer network and cryptography to maintain its integrity. The proponents claim that Bitcoin has many properties that could make it an ideal currency for consumers and merchants in a modern digital economy. Aim and tasks. The purpose of article was to determine and analyze impact of Bitcoin ecosystem on global digital economy. The research objectives were as follows: to specify the concept of Bitcoin ecosystem; to study the trends and prospects of cryptocurrencies development; to determine the role of Bitcoin as an alternative mean of preserving capital for investors – «gold bugs»; to compare the influence of gold and Bitcoin on development of a world financial system; to study the importance of Bitcoin and gold as financial assets of digital economy and the role of Bitcoin as a financial instrument inherent in this economy. Research results. The concept of Bitcoin ecosystem, its main components, factors and risks of development in historical and logical aspects are considered. The tendencies and prospects of cryptocurrencies development, particullary Bitcoin, their influence on traditional E-commerce, conduction of micro-payments, calculations in a field of virtual games are investigated. The role of Bitcoin as an alternative mean of capital preservation for a certain type of investors is determined. The comparative analysis of an influence of gold and Bitcoin on development of world financial system in historical aspect has been carried out. The conclusions are made about role of cryptocurrency (bitcoin) and gold as financial assets of digital economy. The role of Bitcoin as a financial tool corresponding to service requirements of actors of digital economy is determined. Conclusion. In last few years in many countries the large-scale Bitcoin-ecosystem and economy has developed with tens of millions of Bitcoins which daily change owners in electronic transactions. These funds still have a small amount relative to the rest of world's trading assets and economy. Today, while the digital currencies work in the semi-legal field in most countries, they may be a danger to national securities laws, be an instrument for tax evasion, illegal banking, money laundering, illicit drug trafficking, etc. This ability should be considered as one of the most unsafe risks of the functioning for Bitcoin ecosystem. But this is just the beginning of transformations for globalized system, since both society, economy and finance will become fully digital. The problem now is how to find right application for cryptocurrency, so that it becomes a paradigm of financial trust for humanity, as was previously with gold.
Jingwei Liu, Xiaolu Li, Lin Ye, Hongli Zhang · 6 authors
Electronic medical record (EMR) is a crucial form of healthcare data, currently drawing a lot of attention. Sharing health data is considered to be a critical approach to improve the quality of healthcare service and reduce medical costs. However, EMRs are fragmented across decentralized hospitals, which hinders data sharing and puts patients' privacy at risks. To address these issues, we propose a blockchain based privacy-preserving data sharing for EMRs, called BPDS. In BPDS, the original EMRs are stored securely in the cloud and the indexes are reserved in a tamper-proof consortium blockchain. By this means, the risk of the medical data leakage could be greatly reduced, and at the same time, the indexes in blockchain ensure that the EMRs can not be modified arbitrarily. Secure data sharing can be accomplished automatically according to the predefined access permissions of patients through the smart contracts of blockchain. Besides, the joint-design of the CP-ABE-based access control mechanism and the content extraction signature scheme provides strong privacy preservation in data sharing. Security analysis shows that BPDS is a secure and effective way to realize data sharing for EMRs.
Samuel Fosso Wamba, Jean Robert Kala Kamdjoug, Ransome Epie Bawack, John G. Keogh
This paper aims to bridge the knowledge gap in the existing literature on Bitcoin, Blockchain and Fintech. It begins by clarifying the definition of these concepts. Through a systematic review and case studies in the supply chain industry, this paper brings out the applications, the benefits/value, and the challenges/issues of Bitcoin, Blockchain and Fintech in several industries. It also presents the research methodologies/approaches used during such research. The classification framework developed and used to perform an analysis of 141 articles from five top academic databases serves as a baseline study. It offers the opportunity to evaluate the level of knowledge on Bitcoin, Blockchain and Fintech, and their evolution over time. The findings show that these technologies are evolving, and organizations are embracing them for competitive advantage. Thus, organizations need to leverage research on these technologies to better understand them, optimize their business strategies, and develop critical insights for decision-making.
Marc Jourdan, Sébastien Blandin, Laura Wynter, Pralhad Deshpande
The Bitcoin transaction graph is a public data structure organized as transactions between addresses, each associated with a logical entity. In this work, we introduce a complete probabilistic model of the Bitcoin Blockchain, setting the basis for follow-up AI applications on Bitcoin transactions. We first formulate a set of conditional dependencies induced by the Bitcoin protocol at the block level and derive a corresponding fully observed graphical model of a Bitcoin block. We then extend the model to include hidden entity attributes such as the functional category of the associated logical agent and derive asymptotic bounds on the privacy properties implied by this model. At the network level, we show evidence of complex transaction-to-transaction behavior and present a relevant discriminative model of the agent categories. Performance of both the block-based graphical model and the network-level discriminative model are evaluated on a subset of the public Bitcoin Blockchain.