Gordon Lemme, Diana Lemme, Kilian Armin Nölscher, Steffen Ihlenfeldt
In a global sales market with networked production steps and increasing complex machine tools, scaling service ecosystems for production provide an adequate solution for handling the generated data. The existing sensor equipment at current and the extension possibility by the System-of-Systems approach for existing machine tools can offer value-added services by the smart handling of production-related data. It is important to make these data validatable and exchangeable, taking into account to different protection goals. The trust of the individual actors in such a volatile value chain and the different (partly cross-border) value creation partners play an important role. The participation of a large number of these actors creates an attractive overall system (ecosystem) with lots of services and network effects. Concerning data security there are numerous aspects, which have not been adequately answered or taken into account in the use of a service ecosystem in the production environment. The paper discusses a distributed ecosystem for production on a distributed ledger-based service ecosystem, in which services can be mapped in the machine tool environment (e.g. calibration). This technology can be used for secure data exchange in order to discuss traceability and unchangeability of data while maintaining data sovereignty.
Abstract There is a wealth of information, hype around, and research into blockchain’s ‘disruptive’ and ‘transformative’ potential concerning every industry. However, there is an absence of scholarly attention given to identifying and analyzing the political premises and consequences of blockchain projects. Through digital ethnography and participatory action research, this article shows how blockchain experiments personify ‘prefigurative politics’ by design: they embody the politics and power structures which they want to enable in society. By showing how these prefigurative embodiments are informed and determined by the underlying political imaginaries, the article proposes a basic typology of blockchain projects. Furthermore, it outlines a frame to question, cluster, and analyze the expressions of political imaginaries intrinsic to the design and operationalization of blockchain projects on three analytic levels: users, intermediaries, and institutions.
The interoperability across multiple or many blockchains would play a critical role in the forthcoming blockchain-based data management paradigm. In particular, how to ensure the ACID properties of those transactions across an arbitrary number of blockchains remains an open problem in both academic and industry: Existing solutions either work for only two blockchains or requires a centralized component, neither of which would meet the scalability requirement in practice. This short paper shares our vision and some early results toward scalable cross-blockchain transactions. Specifically, we design two distributed commit protocols and, both analytically and experimentally, demonstrate their effectiveness.
Philipp Frauenthaler, Marten Sigwart, Christof Spanring, Stefan Schulte
Current blockchain technologies provide very limited means of interoperability. In particular, solutions enabling blockchains to verify the existence of data on other blockchains are either very costly or are not fully decentralized. To overcome these limitations, we introduce Testimonium, a novel blockchain relay scheme that applies a validation-on-demand pattern and the on-chain execution of Simplified Payment Verifications to enable the verification of data across blockchains while remaining fully decentralized. Evaluating the scheme for Ethereum-based blockchains shows that Testimonium achieves a cost reduction of up to 92% over existing solutions. As such, the scheme lays a strong foundation for generic blockchain interoperability. For instance, it enables the development of an atomic-commit protocol for distributed transactions across blockchains.
Panos Kudumakis, Thomas Wilmering, M. Sandler, Victor Rodrı́guez-Doncel · 6 authors
The Moving Picture Experts Group (MPEG) is an International Organization for Standardization/International Electrotechnical Commission (ISO/IEC) working group that develops media coding standards. These standards include a set of ontologies for the codification of intellectual property rights (IPR) information related to media. The Media Value Chain Ontology (MVCO) facilitates rights tracking for fair, timely, and transparent payment of royalties by capturing user roles and their permissible actions on a particular IP entity. The Audio Value Chain Ontology (AVCO) extends MVCO functionality related to the description of IP entities in the audio domain, e.g., multitrack audio and time segments. The Media Contract Ontology (MCO) facilitates the conversion of narrative contracts to digital ones. Furthermore, the axioms in these ontologies can drive the execution of rights-related workflows in controlled environments, e.g., blockchains, where transparency and interoperability is favored toward fair trade of music and media. Thus, the aim of this article is to create awareness of the MPEG IPR ontologies developed in the last few years and the work currently taking place addressing the challenge identified toward the execution of such ontologies as smart contracts on blockchain environments.
Vicent Cholvi, Antonio Fernández Anta, Chryssis Georgiou, Nicolas Nicolaou · 5 authors
A Distributed Ledger Object (DLO) is a concurrent object that maintains a totally ordered sequence of records, and supports two basic operations: append, which appends a record at the end of the sequence, and get, which returns the sequence of records. In this work we provide a proper formalization of a Byzantine-tolerant Distributed Ledger Object (BDLO), which is a DLO in a distributed system in which processes may deviate arbitrarily from their indented behavior, i.e. they may be Byzantine. Our formal definition is accompanied by algorithms to implement BDLOs by utilizing an underlying Byzantine Atomic Broadcast service. We then utilize the BDLO implementations to solve the Atomic Appends problem against Byzantine processes. The Atomic Appends problem emerges when several clients have records to append, the record of each client has to be appended to a different BDLO, and it must be guaranteed that either all records are appended or none. We present distributed algorithms implementing solutions for the Atomic Appends problem when the clients (which are involved in the appends) and the servers (which maintain the BDLOs) may be Byzantine.
The global Electronic Health Record (EHR) market is growing dramatically and has already hit $31.5 billion in 2018. To safeguard the security of EHR data and privacy of patients, fine-grained information access and sharing mechanisms are essential for EHR management. This paper proposes a hybrid architecture of blockchain and edge nodes to facilitate EHR management. In this architecture, we utilize attribute-based multi-signature (ABMS) scheme to authenticate user's signatures without revealing the sensitive information and multi-authority attribute-based encryption (ABE) scheme to encrypt EHR data which is stored on the edge node. We develop the blockchain module on Hyperledger Fabric platform and the ABMS module on Hyperledger Ursa library. We measure the signing and verifying time of the ABMS scheme under different settings, and experiment with the authentication events and access activities which are logged as transactions in blockchain.
Daniel J. Moroz, Daniel J. Aronoff, Neha Narula, David C. Parkes
Proof-of-Work mining is intended to provide blockchains with robustness against double-spend attacks. However, an economic analysis that follows from Budish (2018), which considers free entry conditions together with the ability to rent sufficient hashrate to conduct an attack, suggests that the resulting block rewards can make an attack cheap. We formalize a defense to double-spend attacks. We show that when the victim can counterattack in the same way as the attacker, this leads to a variation on the classic game-theoretic War of Attrition model. The threat of this kind of counterattack induces a subgame perfect equilibrium in which no attack occurs in the first place.
Speech is a natural user interface for the Internet of Things system. However, the presence of noise affects severely the performance of such system. With the deployment of smart devices with microphones, one can form a powerful acoustic sensor network to enhance the speech via beamforming techniques. On the other hand, reliability of data transmission also determines the beamforming performance, since faulty data will drift the beamformer steering location randomly. Currently, there is no protection scheme for acoustic data transmitted over the wireless network in order to keep steady beamforming performance. In this article, we design a compound distributed beamformer, where nodes are grouped and the system is embedded with blockchain technology to protect the data integrity during transmission. It attempts to provide more possible reliable connections between groups. Simulated experiments show that the distributed beamformer with blockchain protection is able to maintain steady beamforming performance.
ابزارهای مبادلاتی نوین در عصر حاضر نقشی غیرقابل انکار در توسعه تجارت الکترونیکی بر عهده دارند. یکی از این ابزارها قراردادهای هوشمند هستند که در مقایسه با دیگر انواع قراردادهای الکترونیکی دارای خصوصیاتی از جمله سرعت و امنیت بالا هزینه کم در تشکیل قرارداد میباشند. پژوهش حاضر به روش اسنادی به دنبال پاسخگویی به این سؤال است که سیاستگذاری قواعد عمومی تشکیل قراردادها در مرحله انعقاد قراردادهای هوشمند با چه چالشهایی مواجه است؟ بهطور کلی مهمترین چالشهای موجود مطابقت قواعد حاکم بر این قراردادها با هنجارهای موجود در جامعه، تعارض قوانین داخلی کشورها با یکدیگر و مقررات بینالمللی، اعتبارسنجی این قراردادها و ابزارهای انعقاد آنها از جمله ارزهای مجازی، سازوکار عملکرد هوش مصنوعی و ماهیت متمرکز پایگاههای اطلاعاتی و هوش مصنوعی میباشد. رفع چالشهای مذکور نیازمند برخی سیاستگذاریهای تقنینی و اجرایی از جمله تصویب قوانین کارآمد در جهت اعتبارسنجی قراردادهای هوشمند و ارزهای مجازی، اصلاح قوانین متعارض موجود، پیشبینی تشریفات تخصیص مجوز تملک ارزهای مجازی و بهرهمندی از امضائات دیجیتالی، آگاهی بخشی به مردم و تعیین نهادهای ناظر خواهد بود.
Tsung-Ting Kuo, Rodney A. Gabriel, Krishna R. Cidambi, Lucila Ohno‐Machado
OBJECTIVE: Predicting patient outcomes using healthcare/genomics data is an increasingly popular/important area. However, some diseases are rare and require data from multiple institutions to construct generalizable models. To address institutional data protection policies, many distributed methods keep the data locally but rely on a central server for coordination, which introduces risks such as a single point of failure. We focus on providing an alternative based on a decentralized approach. We introduce the idea using blockchain technology for this purpose, with a brief description of its own potential advantages/disadvantages. MATERIALS AND METHODS: We explain how our proposed EXpectation Propagation LOgistic REgRession on Permissioned blockCHAIN (ExplorerChain) can achieve the same results when compared to a distributed model that uses a central server on 3 healthcare/genomic datasets, and what trade-offs need to be considered when using centralized/decentralized methods. We explain how the use of blockchain technology can help decrease some of the problems encountered in decentralized methods. RESULTS: We showed that the discrimination power of ExplorerChain can be statistically similar to its counterpart central server-based algorithm. While ExplorerChain inherited some benefits of blockchain, it had a small increased running time. DISCUSSION: ExplorerChain has the same prerequisites as a distributed model with a centralized server for coordination. In a manner similar to secure multi-party computation strategies, it assumes that participating institutions are honest, but "curious." CONCLUSION: When evaluated on relatively small datasets, results suggest that ExplorerChain, which combines artificial intelligence and blockchain technologies, performs as well as a central server-based method, and may avoid some risks at the cost of efficiency.
Tobias Riasanow, Lea Jäntgen, Sebastian Hermes, Markus Böhm · 5 authors
Abstract Digital transformation is continuously changing ecosystems, which also forces established companies to re-evaluate their value proposition. However, only transformations of single ecosystems have been studied. Therefore, this work targets to examine the similarities of digital transformation in five platform ecosystems: automotive, blockchain, financial, insurance, and IIoT. For our analysis, we combine the strengths of conceptual modeling using e3 value with a cluster analysis based on text mining to identify similarities in the respective ecosystems. As a result, we identified 15 clusters. Cluster 01 is the core cluster, containing the roles of organizations from all five ecosystems. Cluster 02–05 are intertwined, as they include roles from at least two ecosystems. Clusters 06–15 are ecosystem-specific that only include roles found in one ecosystem. Scholars and practitioners can use these clusters when analyzing or building a new platform ecosystem, or transforming a traditional ecosystem towards a platform ecosystem.
Globalization and high technological applications that shape modern life, it creates unique needs in the financial world and payment methods and leads to changes in the ways in which money is used. While the change has spread the use of virtual and crypto money, it offers signs that it will gain more place in life in the future. This makes the knowledge of young people, who grow up in the technology-dominated world and will be one of the main determinants of the use and management of money in the future, important for predicting the future use of money. The main purpose of the research is to determine the knowledge of tourism education individuals about Bitcoin money type and their use of this money. In addition, the research aims to determine the views of the participants about how the Crypto currency use will be shaped in the future. In this context, data collected 214 participants from Anadolu University Faculty of Tourism and were evaluated with descriptive analysis and difference analysis. The results show that although the participants know Bitcoin, they do not have a deep knowledge of the money and its usage areas and that they provide the opinion that the crypto money will be used in the most purchase and trade transactions in the future. In this context, suggestions were given to the researchers who will deal with crypto money in the context of tourism sector in the future and to entrepreneurs who tend to use the crypto money in their enterprises
Ludwig Trotter, Mike Harding, Chris Elsden, Nigel Davies · 5 authors
We demonstrate Smart Donations, a blockchain powered mobile platform and application that facilitates a novel model for real-time, condition-based donations using smart contracts. By leveraging the benefits of blockchain technology, Smart Donations empower donors to (i) attach conditions dependent on real-world phenomena to a donation, (ii) store funds in a secure, transparent and decentralised escrow, and (iii) automatically release funds to charitable organisations or particular projects once the donor's conditions have been met. We believe this mobile prototype demonstrates a compelling new approach to charitable giving that leverages dynamic pledge controls and considers new trust relationships between donors and NGOs.
High availability of data is responsible for the current trends in Artificial\nIntelligence (AI) and Machine Learning (ML). However, high-grade datasets are\nreluctantly shared between actors because of lacking trust and fear of losing\ncontrol. Provenance tracing systems are a possible measure to build trust by\nimproving transparency. Especially the tracing of AI assets along complete AI\nvalue chains bears various challenges such as trust, privacy, confidentiality,\ntraceability, and fair remuneration. In this paper we design a graph-based\nprovenance model for AI assets and their relations within an AI value chain.\nMoreover, we propose a protocol to exchange AI assets securely to selected\nparties. The provenance model and exchange protocol are then combined and\nimplemented as a smart contract on a permission-less blockchain. We show how\nthe smart contract enables the tracing of AI assets in an existing industry use\ncase while solving all challenges. Consequently, our smart contract helps to\nincrease traceability and transparency, encourages trust between actors and\nthus fosters collaboration between them.\n
An approach to the modelling of volatile time series using a class of uniformity-preserving transforms for uniform random variables is proposed. V-transforms describe the relationship between quantiles of the stationary distribution of the time series and quantiles of the distribution of a predictable volatility proxy variable. They can be represented as copulas and permit the formulation and estimation of models that combine arbitrary marginal distributions with copula processes for the dynamics of the volatility proxy. The idea is illustrated using a Gaussian ARMA copula process and the resulting model is shown to replicate many of the stylized facts of financial return series and to facilitate the calculation of marginal and conditional characteristics of the model including quantile measures of risk. Estimation is carried out by adapting the exact maximum likelihood approach to the estimation of ARMA processes and the model is shown to be competitive with standard GARCH in an empirical application to Bitcoin return data.
Jacques Bou Abdo, Rayane El Sibai, Krishna Kambhampaty, Jacques Demerjian
Reputation‐based consensus algorithms are one of the most promising, but least investigated types of consensus algorithms. Its limitation to persmissioned node identity management shades its potential and causes many applications to find blockchain unsuitable. In this paper, we upgrade PoRX, an existing consensus algorithm, into becoming the first permissionless pure reputation‐based consensus algorithm. This upgrade is highly potential since it only affects the admission process and does not intervene with the consensus process, thus can be extended into other types of consensus algorithms.
The purpose of this paper is to provide a review of Islamic Microfinance and its application as a tool for poverty reduction, especially in developing countries. This system of financing serves as an alternative to the interest-based loans from conventional banks as well as conventional microfinance Institutions to the poor yet Islamic conscious millions of Muslims. This paper takes a descriptive approach and relied upon the available literature on Islamic Microfinance to highlight the different approaches used in different parts of the world. The conclusion from the review showed Islamic microfinance as doing well in poverty reduction, women empowerment, and being efficient in its operations.
Gijs van Leeuwen, Tarek AlSkaif, Madeleine Gibescu, Wilfried van Sark
In this paper, an integrated blockchain-based energy management platform is proposed that optimizes energy flows in a microgrid whilst implementing a bilateral trading mechanism. Physical constraints in the microgrid are respected by formulating an Optimal Power Flow (OPF) problem, which is combined with a bilateral trading mechanism in a single optimization problem. The Alternating Direction Method of Multipliers (ADMM) is used to decompose the problem to enable distributed optimization and a smart contract is used as a virtual aggregator. This eliminates the need for a third-party coordinating entity. The smart contract fulfills several functions, including distribution of data to all participants and executing part of the ADMM algorithm. The model is run using actual data from a prosumer community in Amsterdam and several scenarios of the model are tested to evaluate the impact of combining physical constraints and trading on social welfare of the community and scheduling of energy flows. The scenario variants are trade-only, where only a trading mechanism is implemented, grid-only where only OPF optimization is implemented and a combined scenario where both are implemented. Results are compared with a baseline scenario. Simulation results show that import costs of the whole community are reduced by 34.9% as compared to a baseline scenario, and total energy import quantities are reduced by 15%. Total social welfare is found to be highest without a trading mechanism, however this platform is only viable when all costs are equally shared between all households. Furthermore, peak imports are reduced by over 50% in scenarios including grid constraints.
Enterprise blockchain solutions attempt to solve the crucial matter of user privacy, albeit that blockchain was initially directed towards full transparency. In the context of Know Your Customer (KYC) standardization, a decentralized schema that enables user privacy protection on enterprise blockchains is proposed with two types of developed smart contracts. Through the public KYC smart contract, a user registers and uploads their KYC information to the exploited IPFS storage, actions interpreted in blockchain transactions on the permissioned blockchain of Alastria Network. Furthermore, through the public KYC smart contract, an admin user approves or rejects the validity and expiration date of the initial user’s KYC documents. Inside the private KYC smart contract, CRUD (Create, read, update and delete) operations for the KYC file repository occur. The presented system introduces effectiveness and time efficiency of operations through its schema simplicity and smart integration of the different technology modules and components. This developed scheme focuses on blockchain technology as the most important and critical part of the architecture and tends to accomplish an optimal schema clarity.
Open access
Blockchain Technology Applications and Security
Advanced Steganography and Watermarking Techniques
The paper develops a logical understanding of processes for signature of legal contracts, motivated by applications to legal recognition of smart contracts on blockchain platforms. A number of axioms and rules of inference are developed that can be used to justify a ``meeting of the minds'' precondition for contract formation from the fact that certain content has been signed. In addition to an ``offer and acceptance'' process, the paper considers ``signature in counterparts'', a legal process that permits a contract between two or more parties to be brought into force by having the parties independently (possibly, remotely) sign different copies of the contract, rather than placing their signatures on a common copy at a physical meeting. It is argued that a satisfactory account of signature in counterparts benefits from a logic with syntactic self-reference. The axioms used are supported by a formal semantics, and a number of further properties of the logic are investigated. In particular, it is shown that the logic implies that when a contract has been signed, the parties do not just agree, but are in mutual agreement (a common-knowledge-like notion) about the terms of the contract.
We investigate the behaviour of cryptocurrencies using data for bitcoin, ethereum and ripple which account for over 70% of the cryptocurrency market. We demonstrate that $α$-stable distribution is an appropriately sufficient model for highly speculative cryptocurrencies which outperforms other heavy tailed distributions that are used in financial econometrics. We find that the maximum likelihood method proposed by DuMouchel (1971) produces estimates that fit the cryptocurrency return data much better than the quantile based approach of McCulloch (1986) and sample characteristic method by Koutrouvelis (1980). The empirical results show that the leptokurtic feature presented in cryptocurrency return data can be captured by an $α$-stable distribution. The findings highlight that $α$-stable distribution is not only parsimonious with its four free parameters but also a creative model that is close to reality. This paper covers early reports and literature on cryptocurrencies and stable distributions.
Ariel Futoransky, Carlos Sarraute, Daniel Fernandez, Matias Travizano · 5 authors
We construct a privacy-preserving, distributed and decentralized marketplace where parties can exchange data for tokens. In this market, buyers and sellers make transactions in a blockchain and interact with a third party, called notary, who has the ability to vouch for the authenticity and integrity of the data. We introduce a protocol for the data-token exchange where neither party gains more information than what it is paying for, and the exchange is fair: either both parties gets the other's item or neither does. No third party involvement is required after setup, and no dispute resolution is needed.