The emergence of big data and Artificial Intelligence (AI) technology is reshaping the world. While the technological revolution improves the quality of our life, new concerns are triggered. The superhuman capability enables AI to outperform human workers in many data- and/or computing-intensive tasks. Also, digital superpowers are showing arrogance towards individuals, which erodes the trust foundation of the society. In this position paper, we suggest to construct trustworthy and safe communities based on a BLockchain-Enabled Social credits System (BLESS) that rewards the residents who commit in socially beneficial activities. Human being's true value lies in serving other people. The BLESS system is considered as an efficient approach to promote the value and dignity in efforts focused on enhancing our communities and regulating business and private behaviors. The BLESS system leverages the decentralized architecture of the blockchain network, which not only allows grassroots individuals to participate rating process of a social credit system (SCS), but also provides tamper proof of transaction data in the trustless network environment. The anonymity in blockchain records also protects individuals from being targeted in the fight against powerful enterprises. Smart contract enabled authentication and authorization strategy prevents any unauthorized entity from accessing the credit system. The BLESS scheme is promising to offer a secure, transparent and decentralized SCS.
Traditionally, the Net Present Value method has been used to compare diverging investment strategies. However, valuating crypto-projects with fiat-based currency is confusing due to extreme coin appreciation rates as compared to fiat interest rates. Here, we provide a net present value method based on using crypto-coin as the underlying asset. Using this method, we compare buy-and-hold versus mine-and-hold; we also provide a sensitivity analysis of profitability.
Agri-food trade has a profound impact on social stability and sustainable economic development. However, there are several technological problems in current agricultural product transactions. For example, it is almost impossible to improve the efficiency of transactions and maintain market stability. This paper designs a novel Food Trading System with COnsortium blockchaiN (FTSCON) to eliminate information asymmetry in the food trade, in order to establish a sustainable and credible trading environment, the system uses consortium blockchain technology to meet the challenge of different authentications and permissions for different roles in food trade. Meanwhile, we have used the online double auction mechanism to eliminate competition. We also have designed a improved Practical Byzantine Fault Tolerance (iPBFT) algorithm to improve efficiency. In addition, a case study based on a series of data from Shandong Province, China indicate that the FTSCON can achieve profit improvement of merchants. Therefore, the proposed system proved to have high commercial value.
Marco Conoscenti, Antonio Vetrò, Juan Carlos De Martin, Federico Spini
The Lightning Network (LN) is one of the most promising off-chain scaling solutions for Bitcoin, as it enables off-chain payments which are not subject to the well-known blockchain scalability limit. In this work, we introduce CLoTH, a simulator for HTLC payment networks (of which LN is the best working example). It simulates input-defined payments on an input-defined HTLC network and produces performance measures in terms of payment-related statistics (such as time to complete payments and probability of payment failure). CLoTH helps to predict issues and obstacles that might emerge in the development stages of an HTLC payment network and to estimate the effects of an optimisation action before deploying it. We conducted simulations on a recent snapshot of the HTLC payment network of LN. These simulations allowed us to identify network and payments configurations for which a payment is more likely to fail than to succeed. We proposed viable solutions to avoid such configurations.
Blockchain is based on a P2P network, supporting decentralized consensus of current cryptocurrencies. Since bitcoin and altcoins all utilize an underlying blockchain, they are therefore greatly affected by the performance of the P2P network. In bitcoin, the miners are engaged in a time-sensitive competition to solve a Proof-of-Work problem to extend the blockchain. This consequently raises a critical problem to minimize the time between the propagation of a winning block and the beginning of the next round of the competition. This paper proposes a method that selects a node's closest neighbors to make messages propagate in the whole network in time. The method measures the distance from a node to its neighbor using transmission latency; thus, the lower the latency, the closer the neighbor. Simulations showed a good rate of decrease in average propagation latency and maximum propagation latency, compared to the classic method. Furthermore, this paper not only proposes the principle of establishing connections based on latency, but also evaluates the influence of the number of simultaneously established connections.
Fedor Muratov, Andrei Lebedev, Nikolai Iushkevich, Bulat Nasrulin · 5 authors
Consensus in decentralized systems that asynchronously receive events and which are subject to Byzantine faults is a common problem with many real-life applications. Advances in decentralized systems, such as distributed ledger (i.e., blockchain) technology, has only increased the importance of finding performant and secure solutions to consensus of state machine replication in decentralized systems. YAC is a practical decentralized consensus algorithm, that solves the problems of inefficient message passing and strong leaders that occur in classical Byzantine fault tolerant consensus algorithms. The algorithm is open source and currently is used to provide Byzantine fault tolerant consensus for the Hyperledger Iroha blockchain project. We provide proofs of safety and liveness, as well as empirical results showing that our algorithm can scale to dozens of validating peers.
Marian Gidea, Daniel Goldsmith, Yuri A. Katz, Pablo Roldan · 5 authors
We analyze the time series of four major cryptocurrencies (Bitcoin, Ethereum,\nLitecoin, and Ripple) before the digital market crash at the end of 2017 -\nbeginning 2018. We introduce a methodology that combines topological data\nanalysis with a machine learning technique -- $k$-means clustering -- in order\nto automatically recognize the emerging chaotic regime in a complex system\napproaching a critical transition. We first test our methodology on the complex\nsystem dynamics of a Lorenz-type attractor, and then we apply it to the four\nmajor cryptocurrencies. We find early warning signals for critical transitions\nin the cryptocurrency markets, even though the relevant time series exhibit a\nhighly erratic behavior.\n
Mario Dobrovnik, David M. Herold, Elmar Fürst, Sebastian Kummer
Despite the claim that blockchain will revolutionise business and redefine logistics, existing research so far is limited concerning frameworks that categorise blockchain application potentials and their implications. In particular, academic literature in transport and logistics to date has not sufficiently distinguished between blockchain adoption (‘what to adopt’) and the identification of the right business opportunity (‘where to start’). In response, this paper (1) uses Rogers’ (2003) ‘attributes of innovation framework’ to identify potential blockchain applications and (2) presents a framework explicating four transformation phases to subsequently categorise the identified areas of application according to their effects on organisational structures and processes. Using academic and practitioner literature, we classify possible applications for adoption and provide a framework to identify blockchain opportunities in the logistics industry, thereby helping managers to systematically assess where to start building organisational capabilities in order to successfully adopt and deploy blockchain-based technology.
A wide range of services and applications can be improved and/or solved by\nusing distributed ledger technology (DLT). These services and applications have\nwidely varying quality of service (QoS) requirements. However, most existing\nDLT systems do not distinguish different QoS requirements, resulting in\nsignificant performance issues such as poor scalability and high cost. In this\nwork, we present vDLT -- a service-oriented blockchain system with\nvirtualization and decoupled management/control and execution. In vDLT,\nservices and applications are classified into different classes according to\ntheir QoS requirements, including confirmation latency, throughput, cost,\nsecurity, privacy, etc. This is a paradigm shift from the existing\n"blockchain-oriented" DLT systems to next generation "service-oriented" DLT\nsystems. Different QoS requirements are fulfilled by advanced schemes inspired\nby the development of the traditional Internet, including classification,\nqueuing, virtualization, resource allocation and orchestration, and\nhierarchical architecture. In addition, management/control and execution of\nsmart contracts are decoupled to support QoS provisioning, improve\ndecentralization, and facilitate evolution in vDLT. With virtualization,\ndifferent virtual DLT systems with widely varying characteristics can be\ndynamically created and operated to accommodate different services and\napplications.\n
The aim of the article is to determine the nature of and justify the priorities for improving the efficiency of budget expenditures in the context of institutional changes in the government finance system. It is proposed to consider the category of cost-effectiveness in the context of fulfilling the objectives of fiscal policy, in particular, those concerning ensuring macroeconomic stability and creating incentives for economic growth, and of results achieved in improving the welfare of the population. An analysis of the trends in changes of the share of expenditures of the consolidated budget of Ukraine as a percentage of GDP for the period from 1992 to 2017 is carried out. The average forecast of this indicator for 2017–2021 is presented. It is identified that in the period of economic growth, the domestic budget policy was pro-cyclical in nature. The increase in expenditure weights was carried out without systemic institutional changes in government finance, which affected the decrease in cost-effectiveness and unbalanced the budget system in the following budget periods. The importance of fiscal decentralization in ensuring the growth of the overall level of budgetary performance is substantiated. The directions for improving the efficiency of budget expenditures on education and science, health care, social protection, and social security are proposed. The necessary changes in the functioning of the higher education system are modernizing the financial basis to conduct scientific research and implement their results in the educational process; focusing on the applied aspects of studying a specialty; developing mechanisms to assess the quality of higher education; providing financial independence to educational institutions. Important aspects of the public policy are the further introduction of the insurance and fee-for-service medicine on the basis of co-financing; compiling of the basic list and standards of relevant medical services guaranteed by the state, financed by the budget. In the field of social protection, it is advisable to develop tools to ensure the targeting of the benefits provided and streamline the categories of recipients.
Money is one of the powerful institutions that humankind created and developed and nowadays it affects all of aspects of social human life. Money essentially is production of human socialization and we should think of it as a social reality that although has a special and independent role for each individual, but it has overall acceptance in the society. Bitcoin is a decentralized electronic fiat currency implemented using cryptography and peer-to-peer technology. Because of increasing development of bitcoin and also other similar currencies, our monetary policy-makers should take proper position about it. In this study we make an analysis about value of bitcoin in context of Etebariat theory developed by Allameh Tabataba’i and argue that value of bitcoin is consistent with this context. Our study about monetary and banking schools like metalism, chartalism, money in circle and banking shows that because of peer-to-peer system of Bitcoin, although Bitcoin is inconsistent with all of the abovementioned theories, but it is consist with Etebariat theory because of no need to third party. So Bitcoin is a counter-example to classical theory of money and it verify Etebariat theory.
John Weru is a Kenya-born writer, blogger and co-founder of PayHub East Africa. In a conversation with ICT Update, John talked about the rise of cryptocurrency, the potential of the blockchain to improve efficiency in the agricultural value chain in Africa, and theurgent need to educate people about the technology itself and the economy that it is creating.
Bitcoin it is digital currency used for any Electronic Financial Transactions, created in 2008 by Satoshi Nakamoto as Peer-to-Peer Electronic System cash. The precise prediction of bitcoin exchange rate with respect to the US dollar is an essential matter because it effected on the world economic constancy. Meanwhile the technology that used in Bitcoin has flickered a revolution in world. This paper aim to a survy on the use artificial neural networks to predict the exchange rate of a Bitcoin(BTC ) currency. https://doi.org/10.24897/acn.64.68.172
In the present article, we analyze the transaction fees market on smart contracts-enabling blockchains. On such systems, as opposed to traditional on-premise and cloud computing solutions, users are effectively competing for computational resources through an auction for priority. This paper proposes a way to estimate the bid one has to offer to have a transaction included in the next block. This method outperforms naive bidding (bidding the optimal value of the last block) if the user is realistically "impatient" to have a transaction processed. It also shows that users collectively spend several million of dollar every years for transaction fees that could be avoided without degrading the service received. This is this "waste" we seek to reduce throughour forecasting method.
BlAsT is an efficient scheme for achieving certification of data continuity through a history attached to a public blockchain. The scheme guarantees the properties of linearity, non-equivocation, time-stamping and transparency. We discuss the implementation of BlAsT over the Bitcoin and the Ethereum blokchains, provide a techno-economic analysis to evaluate the costs related to blockchain adoption, and numerically assess the performance of the proposed architecture in terms of storage and bandwidth requirements. Results show that the above properties can be guaranteed with a small cryptocurrency payment. The proposed scheme can be used for IoT devices under the assumption that the device is able to either perform blockchain validation or delegate it to a trusted node.
The penetration of renewable energy resources and demand response programs causes several management issues, such as network instability. Several research projects are currently investigating and surveying several methods to enhance the network reliability. This paper represents a smart model of community grid that contains a central management unit and several consumers, producers and prosumers. In the proposed model, the community manager is able to control the consumption and generation of the resources by establishing contracts with its members. The community manager utilizes a single period optimization problem for minimizing its operation costs by applying different types of demand response programs and the use of renewable resources. In the case study, an internal low voltage distribution network of a real university campus is considered as the community grid, in order to test and validate the proposed model.
Paula Peña, Rocío Aznar, Rosa Montañés, Rafael Alonso
The project presented has been financed by Government of Aragon and is part of the ''Open Data'' initiative promoted by that organization. Given the amount of unstructured information related to the Government of Aragon currently published on the Internet, with slightly or no standardization and decentralized, it emerges the need to gather it systematically to be offered to all interested collectives from a single access point in a public and structured way. Within this context, ''Aragon Open Data'' project aims to collect, organize, store and maintain updated, Administration''s web information by means of human language and semantic technologies. Firstly, crawling is performed over websites in order to retrieve textual data over which Natural Language Processing (NLP) and ontology-based techniques are applied. Thereafter, results are stored into NoSQL databases, allowing future open access and simple data exploitation. NLP techniques used in the project involve named-entities recognition and classification (NERC) and texts semantic classification and summarization.
Elli Androulaki, Christian Cachin, Angelo De, Eleftherios Kokoris Kogias
Sharding, or partitioning the system’s state so that different subsets of participants handle it, is a proven approach to building distributed systems whose total capacity scales horizontally with the number of participants. Many distributed ledgers have adopted this approach to increase their performance, however, they focus on the permissionless setting that assumes the existence of a strong adversary. In this paper, we deploy channels for permissioned blockchains. Our first contribution is to adapt sharding on asset-management applications for the permissioned setting, while preserving liveness and safety even on transactions spanning across-channels. Our second contribution is to leverage channels as a confidentiality boundary, enabling different organizations and consortia to preserve their privacy within their channels and still be part of a bigger collaborative ecosystem. To make our system concrete we map it on top of Hyperledger Fabric.
Fear of stigmatization and discrimination from colleagues, friends and family drives patients with various type of mental health problems away from a traditional face-to-face therapy and enforces them to look for an alternative treatment methods. Internet-based mental health therapy helps patients to get their needed therapies and support from healthcare professional and peers, or as a part of automated online form of therapy. Conducting Internet based therapy anonymously is vital for the patient privacy. However, lack of trust, access permission, ownership control and traceability undermines patient safety and security. Blockchain technology is an innovative technology initially designed for a cryptocurrency. However, with the introduction of programming blockchain and smart contracts, the technology has extended its importance to other areas for developing decentralized application (DApp), such as mental health related information management, which is the primary focus of this thesis. Privacy and security are very crucial for patient safety and to preserve patient’s medical history from adversaries. Sharing of private medical information online between the patient and their respective provider contains sensitive information that can easily be compromised if a proper security measure is not put in place. Blockchain is consensus-based peer-to-peer distributed ledger technology that stores and maintains an updated copy of all transactions within the network. It makes trust more transparent and traceable by keeping auditable-logs of all transactions in the form of blocks. In this thesis, Blockchain and its underlying technology are studied, and a prototype has been developed to explore the potential of the blockchain technology. Furthermore, we explore alternative distributed ledger technologies and their respective security models such as consensus protocols, cryptographic techniques, privacy and scalability. The prototype was proposed based on Ethereum blockchain.
Open access
Artificial Intelligence in Healthcare and Education
Cryptocurrencies have been in vogue ever since Bitcoin first appeared in 2008. From that moment on, a new potential market started evolving and is nowadays a daily topic for everyone involved in the financial and monetary markets. Cryptocurrencies presented themselves as a viable alternative to traditional currencies, with a lot of new interesting features, but also several aspects that split the opinions between those who understand it as a great alternative for the future and the more skeptical ones who still question its legality and use. Nowadays, cryptocurrency is one of the most interesting topics in the financial markets due to all the controversy associated, as well as the public acceptance, responsible for the huge prices that these coins have been reaching. In this dissertation, we aim to analyze every aspect concerning cryptocurrencies. With the intention to clarify the most important details about this new market, all these details have been scrutinized, from the several different types of cryptocurrencies and its behavior, to the factors that have an impact in cryptocurrencies prices. Cryptocurrency is still a trendy and unknown subject to many people, and that was the motivation and the main objective of this dissertation, to clarify everyone about this topic before thinking of investing in any of these new cryptocurrencies.
Ross Guttromson, Stephen Verzi, Lon Andrew Dawson, Drew Levin · 10 authors
This project explored coupling modeling and analysis methods from multiple domains to address complex hybrid (cyber and physical) attacks on mission critical infrastructure. Robust methods to integrate these complex systems are necessary to enable large trade-space exploration including dynamic and evolving cyber threats and mitigations. Reinforcement learning employing deep neural networks, as in the AlphaGo Zero solution, was used to identify "best" (or approximately optimal) resilience strategies for operation of a cyber/physical grid model. A prototype platform was developed and the machine learning (ML) algorithm was made to play itself in a game of 'Hurt the Grid'. This proof of concept shows that machine learning optimization can help us understand and control complex, multi-dimensional grid space. A simple, yet high-fidelity model proves that the data have spatial correlation which is necessary for any optimization or control. Our prototype analysis showed that the reinforcement learning successfully improved adversary and defender knowledge to manipulate the grid. When expanded to more representative models, this exact type of machine learning will inform grid operations and defense - supporting mitigation development to defend the grid from complex cyber attacks! This same research can be expanded to similar complex domains.
Open access
Smart Grid Security and Resilience
Distributed and Parallel Computing Systems
Infrastructure Resilience and Vulnerability Analysis
This paper build the foundations of a simulation tool for blockchain-based applications. It takes advantage of the huge expressiveness and extensibility of PyCATSHOO framework to deal with the important variability of blockchain implémentations and properties of interest. A simple stochastic model of generic blockchain-style distributed consensus system and associated performance indicators are proposed (performance in terms of consistency and ability to discard double-spending attacks). Monte Carlo simulations are applied to assess the indicators and determine their sensitivity to the variation of input parameters.
Panayiotis Christodoulou, Klitos Christodoulou, Andreas S. Andreou
A prototypical smart contract (wrapped as a decentralized application) is presented for investigating the potential benefits for applying Blockchain for Logistics. The decentralized application proposed exposes the various design challenges that programmers are likely to face when realizing the implementation of the application. The proposed methodology utilises the implementation of a dedicated smart contract that was developed based on a special-purpose structure for satisfying the requirements of the usecase. The evaluation was based on the execution of each of the functions measuring the gas costs and execution time. The prototype design was deployed and evaluated on a real-world Blockchain framework and can be considered as a first solution to how the Blockchain technology can be utilized within Logistics to overcome any barriers that may exist between professionals. In this paper we present a real implementation of a smart contract for the Logistics industry. The proposed dApp provides a live example of how Blockchain can be utilized within Logistics as it enables users to send and track products.
Sofia Alexaki, George Alexandris, Vasilios Katos, Nikolaos E. Petroulakis
Circular, data-driven healthcare is increasingly being considered as an effective model to provide efficient, cost-effective and sustainable healthcare services in the future. Central to this model is the service-dominant “building-block”-type provision of care services to patients, paired with the collaboration of healthcare providers through a common infrastructure. This combination enables the forming of a decentralized, holistic care cycle. Sharing of patient medical informationis pivotal towards reaching this goal; however, preserving medical record integrity and privacy, while at the same time allowing provider interoperability are often conflicting requirements. Blockchains and Smart Contracts can provide the underlying technology to support the decentralized care cycle by addressing patient privacy and medical record integrity, while simultaneously offering efficient interoperability between providers. To demonstrate how this could be achieved, a conceptual medical record access and sharing mechanism is presented which is suitable for a system operating within a regulated healthcare jurisdiction.