Simona Ibba, Andrea Pinna, Maria Ilaria Lunesu, Michele Marchesi · 5 authors
An ICO (Initial Coin Offering) is an innovative way to fund projects based on blockchain. The funding is based on the selling of tokens by means of decentralized applications called smart contracts written in Solidity, a programming language specific for Ethereum blockchain. The ICOs work in a volatile context and it is crucial that the team is capable of handling constant changes. The Agile methods, proven practices enabling to develop software in presence of changing requirements, could be a means for managing uncertainty. The main goals of this work are to understand software engineering activities related to ICOs, recognize the ICOs developed using Agile methods, and make a comparison between ICOs and Agile ICOs. In addition, we perform a deeper analysis of Agile ICOs concerning project planning, software development, and code features. Our work shows that the roles of the people involved in an ICO can be compared to the typical roles of the SCRUM methodology. The majority of Agile ICOs use tool of testing before storing smart contract on blockchain. Finally, the application of volumetric and complexity software metrics shows that the files of Agile ICOs is on average shorter and less complex than in other smart contracts.
Interventional cardiac electrophysiology (EP) includes conventional and complex catheter ablations of cardiac arrhythmias and management of cardiac implantable electronic devices. The Accreditation Committee of the European Heart Rhythm Association (EHRA) has previously provided cardiologists interested in becoming clinical electrophysiologists with specific curricula, defining requirements both for training centres and trainees.1 Indeed, the presence of a structured EP training programme is of utmost importance in order to ensure high-quality training and comply with the requirements. Nevertheless, so far, very little information is available on EP training status across European Society of Cardiology (ESC) member countries.2,3 Therefore, the purpose of this survey was to obtain detailed information on educational EP training in ESC member countries and to assess the need of certification after completing the EP training. The present survey was conducted by the EHRA Young EP Committee from November 2017 to May 2018. Thirty-seven EHRA Young EP National Ambassadors were contacted to complete the survey. They were contacted by e-mail and/or phone and asked to answer a questionnaire containing information on the status of EP training in their specific country. The following parameters were queried: age at the beginning of medical studies, duration of medical studies, age at the beginning of cardiology training, duration of internal medicine training (if any), duration of cardiology training, features of training (duration/type/level/location), research activities performed during training, proportion of subjects performing a training abroad, need for EP and/or cardiac pacing (CP) certification after completing the training, mean number of centres per country accredited for EP/CP training, institution responsible of the certification (EHRA/National Societies/others). A total of 31 EHRA Young EP National Ambassadors completed the survey (84% response rate). Of the respondents, seven were female (23%). They represented the following ESC member countries: Algeria, Austria, Belarus, Belgium, Bosnia and Herzegovina, Bulgaria, Croatia, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Israel, Italy, Latvia, Lebanon, Lithuania, Malta, Norway, Poland, Portugal, Republic of Ireland, Romania, Serbia, Slovenia, Spain, Sweden, Switzerland, and United Kingdom. The information provided was based on the National Ambassadorâs personal experience or on the mean value of data provided by additional young electrophysiologists who recently completed their training in the country or abroad. Descriptive statistics were analysed using SPSS V.24.0 (SPSS Chicago, IL, USA). Specific features of Cardiology and EP training are listed in Table 1. Mean age at the time of the beginning of medical studies was 19 years, ranging from 17 to 21 years. Mean duration of medical studies was 6 years, typical for ESC member countries. Internal medicine training was required in 27 countries (87%), with a mean duration of 2.5 years (range 6 months to 6 years). The mean age at the end of the cardiology training was 31.6 years, ranging from 27 to 40 years. The mean duration of EP training was 2.5 ± 1.1 years. Structured EP and CP training programmes were offered only in half of countries (49%). The mean number of centres accredited for EP/CP training per country was 10 ± 31 (range 0â149) (Figure 1). A formal EP/CP subspecialization was required in nine countries (29%) and had a mean duration of 2 years. Research activities were requested in about half (48%) of the countries as part of the training. Finally, there was a considerable variability regarding trainees attending an EP training abroad: 55% of the EHRA Young EP Ambassadors declared a rate of less than 20, and 42% of them reported a rate of greater than 50%. Cardiology and EP training features CP, cardiac pacing; EP, electrophysiology. Cardiology and EP training features CP, cardiac pacing; EP, electrophysiology. Number of EP training accredited centres per country. Reported data refer to the number of centres per 10 000 000 inhabitants in each country. Blue colour refers to centres accredited by their national society; red colour refers to EHRA Recognized Training Centres. *Centres with unavailable information. Six ESC member countries (Bulgaria, Estonia, France, Israel, Portugal, Serbia) (19%) require trainees to obtain certification by the respective National Society after their EP/CP training. None of the National Ambassadors reported obligation for the EHRA certification. Nevertheless, most of the EP trainees (72%) voluntarily take the certification exam after finishing their training. The responsible institution covering the costs of the certification was EHRA in 15 countries (68%) and the respective national society in seven countries (32%). This report highlights several features of the status of EP training in the ESC member countries: (i) a relatively high age of trainees initiating an EP training, (ii) high heterogeneity in the type and duration of training offered by each country, (iii) lack of centres offering a structured EP training programme in many countries, and (iv) request of EP/CP certification after completing training only in a minority of centres. All these aspects are of particular relevance when considering the development of structured EP training programmes and the subsequent individual EP career building. In this survey, the mean age of a cardiologist starting an educational EP training programme was 32 years; therefore, the age cut-off for definition of a young electrophysiologist should be defined accordingly. EHRA can play an active and important role in ensuring the achievement of a proper and homogenous EP training level across all ESC countries. Indeed, recently, EHRA supported good educational practices provided by centres by offering training fellowships programmes in EHRA Recognised Training Centres (ERTC). EHRA strives to maintain the highest standards in education and career development. So far, a list of 21 ERTCs using advanced and uniform teaching techniques has been provided. Moreover, EHRA EP training fellowships and proctor programmes have played a crucial role especially in countries with EP under development with a limited access to structured EP training programmes. In addition, EHRA Young EP Committee and the National Ambassadors can have an important role by highlighting potential training obstacles and issues experienced by trainees in each ESC member country, as they are the most involved stake holders in this training process. Finally, obtaining an EHRA certification after completing the training is demanded being a proof of achievement of practical experience and knowledge in cardiac devices and cardiac electrophysiology, and could guarantee high-level competence, knowledge, and skills of the trainees, supporting improved quality arrhythmia healthcare throughout the European countries. Nevertheless, further efforts are needed to continuously improve and develop activities related to EP training and networking within the EHRA Young EP community that will likely contribute to the improvement of the quality of EP training and early career building of young electrophysiologists. Considerable heterogeneity is present across ESC member countries with respect to access and specific characteristics of EP training. EP/CP certification after completing EP training is requested only in a small proportion of countries. However, most of the trainees voluntarily take the certification exam by EHRA or their national societies. Nevertheless, further efforts to harmonize EP training, and certification requirements across ESC member countries are warranted to improve and homogenize EP quality of care. Conflict of interest: none declared.
Zaynah Dargaye, Antonella Del Pozzo, Sara Tucci-Piergiovanni
The paper presents Pluralize a formal logical framework able to extend the execution of blockchain transactions to events coming from external oracles, like external time, sensor data, human-made declarations, etc. These events are by essence non-reliable, since transaction execution can be triggered by information whose veracity cannot be established by the blockchain. To overcome this problem, the language features a first-order logic and an authority algebra to allow formal reasoning and establish accountability of agents for blockchain-enabled transactions. We provide an accountability model that allows to formally prove the accountability of agents by a formal proof locally executable by each agent of the blockchain.
In the present paper, we investigate connectedness within cryptocurrency markets as well as across the Bitcoin index (hereafter, BPI) and widely traded asset classes such as traditional currencies, stock market indices and commodities, such as gold and Brent oil. A spill over index approach with the spectral representation of variance decomposition networks, is employed to measure connectedness. Results show no significant spillover effects between the nascent market of cryptocurrencies and other financial markets. We suggest that cryptocurrencies are real independent financial instruments that pose no danger to financial system stability. Concerning the connectedness within the cryptocurrency markets, we report a timeâfrequencyâdynamics connectedness nature. Moreover, the decomposition of the total spill over index is mostly dominated by a short frequency component (2â4 days) leading to the conclusion that this nascent market is highly speculative at present. These findings provide insights for regulators and potential international investors.
Muhammad Mehar, Charles Louis Shier, Alana Giambattista, Elgar Gong · 8 authors
In spring 2016, the Distributed Autonomous Organization (The DAO) was created on Ethereum. As with Bitcoin, Ethereum uses a P2P network, where distributed ledgers are implemented as daisy-chained blocks of data. Ethereum's native cryptocurrency, Ethers are spent to execute pieces of code called smart contracts. Investors paid their Ethers for the DAO to operate and received the opportunity to vote on and become investors in venture projects proposed by Ethereum-based startups. Transactions and settlements between investors and startups are executed autonomously. The DAO experiment failed shortly after inception as an anonymous hacker stole over $50M USD worth of Ethers out of the $168M invested. The Ethereum community voted to return (or fork) the state of the network to one prior to the hack, returning Ethers back to investors and shuttering the DAO. However, this action arguably represented as a bailoutâironically, Bitcoin was conceived as a reaction against the 2008 bailout of US banksâand violated the ledger immutability and âcode is lawâ ethos of the blockchain community.
In this paper we extend the known methodology for fitting stable distributions to the multivariate case and apply the suggested method to the modelling of daily cryptocurrency-return data. The investigated time period is cut into 10 non-overlapping sections, thus the changes can also be observed. We apply bootstrap tests for checking the models and compare our approach to the more traditional extreme-value and copula models.
S. Keshav, W. Golab, B. Wong, S. Rizvi · 5 authors
Distributed consensus is a key enabler for many distributed systems including distributed databases and blockchains. Canopus is a scalable distributed consensus protocol that ensures that live nodes in a system agree on an ordered sequence of operations (called transactions). Unlike most prior consensus protocols, Canopus does not rely on a single leader. Instead, it uses a virtual tree overlay for message dissemination to limit network traffic across oversubscribed links. It leverages hardware redundancies, both within a rack and inside the network fabric, to reduce both protocol complexity and communication overhead. These design decisions enable Canopus to support large deployments without significant performance degradation. The existing Canopus protocol is resilient in the face of node and communication failures, but its focus is primarily on performance, so does not respond well to other types of failures. For example, the failure of a single rack of servers causes all live nodes to stall. The protocol is also open to attack by Byzantine nodes, which can cause different live nodes to conclude the protocol with different transaction orders. In this paper, we describe RCanopus (`resilent Canopus') which extends Canopus to add liveness, that is, allowing live nodes to make progress, when possible, despite many types of failures. This requires RCanopus to accurately detect and recover from failure despite using unreliable failure detectors, and tolerance of Byzantine attacks. Second, RCanopus guarantees safety, that is, agreement amongst live nodes of transaction order, in the presence of Byzantine attacks and network partitioning.
Italian Abstract: Blockchain puo significare anche riorganizzazione dei sistemi di sicurezza sociale. Di qui l'idea di approfondire l'applicazione possibile della blockchain a alcuni istituti previdenziali, tra cui il distacco europeo, l'invalidita e il REI, per definire il quadro delle potenzialita e delle criticita. Nel saggio si studia anche il concetto di smart contract.
English Abstract: Blockchain technologies and smart contracts can be applied to social security systems. The paper is aimed at investigating the possible social fields of such application, the legal consequences, the critical points. Posting and invalidity benefits regimes are examined in light of the possible application of blockchain.
In this paper we extend the known methodology for fitting stable\ndistributions to the multivariate case and apply the suggested method to the\nmodelling of daily cryptocurrency-return data. The investigated time period is\ncut into 10 non-overlapping sections, thus the changes can also be observed. We\napply bootstrap tests for checking the models and compare our approach to the\nmore traditional extreme-value and copula models.\n
Chengjun Cai, Jian Weng, Xingliang Yuan, Cong Wang
Blockchain has led the trend of decentralized applications and shown great use beyond cryptocurrencies. Decentralized storage such as Storj and Sia leverages blockchain to establish an open platform for sharing economy, which provides private and reliable file-outsourcing services. However, the ubiquitous keyword search function over encrypted files is yet to be supported. To enable this function, we first apply searchable encryption techniques to the decentralized setting. But this primitive can hardly ensure the service integrity. The reason is that decentralized storage commonly faces severe threats from both clients and service peers. Service peers may return partial or incorrect results, while clients may intentionally slander the service peers to avoid payments. To address these threats, we utilize the smart contract to record the logs of encrypted search (aka evidence) on the blockchain, and devise a fair protocol to handle disputes and issue fair payments. Using a dynamic-efficient searchable encryption scheme as an instantiation, we craft a concrete scheme that preserves encrypted search capability and enforces ecosystem healthiness, so that service peers are incentivized to make real efforts and jointly guarantee service reliability. We implement our scheme in Python and Solidity, and test its search performance and transaction costs on Ethereum.
With the increase of web users and applications with real time requests, the ability to identify, track and trace elements of a product as it moves in the supply chain is deemed necessary, and for many industries is even mandated by national or international regulations. Traceability presupposes the integrity and transparency of data that is saved and shared. This is a problem for current technologies, as there are many examples with tampered data and database vulnerabilities that resulted in serious implications and data loss. A solution to this problem can be the decentralization of the system, which will remove the central point of failure. To that effect, blockchain or DLT technologies, an emergent technology that enables the decentralization of a network can be used, by implementing a trustless model to achieve it. Blockchains are tamperproof and transparent, which means that by exploiting blockchain characteristics, traceability can be improved. A model that describes the decentralization process of the supply chain traceability part has been developed for this paper and is later evaluated and compared with the traditional system.
We describe \emph{Fantom}, a framework for asynchronous distributed systems. \emph{Fantom} is based on the Lachesis Protocol~\cite{lachesis01}, which uses asynchronous event transmission for practical Byzantine fault tolerance (pBFT) to create a leaderless, scalable, asynchronous Directed Acyclic Graph (DAG). We further optimize the \emph{Lachesis Protocol} by introducing a permission-less network for dynamic participation. Root selection cost is further optimized by the introduction of an n-row flag table, as well as optimizing path selection by introducing domination relationships. We propose an alternative framework for distributed ledgers, based on asynchronous partially ordered sets with logical time ordering instead of blockchains. This paper builds upon the original proposed family of \emph{Lachesis-class} consensus protocols. We formalize our proofs into a model that can be applied to abstract asynchronous distributed system.
Ethereum Private Sidechains are permissioned Ethereum blockchains which allow authorised participants to interact privately using Smart Contracts. Permissioned blockchains are appropriate for use in scenarios in which the list of blockchain participants and the code and state of contracts on the blockchain must be kept secret. Ethereum Registration Authorities are a system of Smart Contracts which can be used to resolve bootstrap information based on domain names to allow Ethereum Private Sidechains to be established between parties which have not previously interacted. This paper presents the architecture, design, and gas usage of a reference implementation for the Ethereum Registration Authority system. It analyses the security properties of the system and shows that it is secure, decentralized, and censorship resistant. The reference implementation gas usage is analysed and shown to be independent of the length of domain name and number of entries in the Smart Contracts.
Ji-Sun Park, Taek-Young Youn, Hye-Bin Kim, Kyung-Hyune Rhee · 5 authors
Internet of Things (IoT)-based devices, especially those used for home automation, consist of their own sensors and generate many logs during a process. Enterprises producing IoT devices convert these log data into more useful data through secondary processing; thus, they require data from the device users. Recently, a platform for data sharing has been developed because the demand for IoT data increases. Several IoT data marketplaces are based on peer-to-peer (P2P) networks, and in this type of marketplace, it is difficult for an enterprise to trust a data owner or the data they want to trade. Therefore, in this study, we propose a review system that can confirm the reputation of a data owner or the data traded in the P2P data marketplace. The traditional server-client review systems have many drawbacks, such as security vulnerability or server administrator's malicious behavior. However, the review system developed in this study is based on Ethereum smart contracts; thus, this system is running on the P2P network and is more flexible for the network problem. Moreover, the integrity and immutability of the registered reviews are assured because of the blockchain public ledger. In addition, a certain amount of gas is essential for all functions to be processed by Ethereum transactions. Accordingly, we tested and analyzed the performance of our proposed model in terms of gas required.
Post-Quantum Cryptography (PQC) attempts to find cryptographic protocols resistant to attacks using Shor polynomial time algorithm for numerical field problems or Grover search algorithm. A mostly overlooked but valuable line of solutions is provided by non-commutative algebraic structures, specifically canonical protocols that rely on one-way trapdoor functions (OWTF). Here we develop an algebraic framework who could be applied to different asymmetric protocols like D-H KE (Diffie-Hellman key exchange), Public Key Encryption, Digital Signature, ZKP (zero-knowledge proof) authentication, Oblivious Transfer, Multi-Party Computing, and so on. The trapdoor one-way functions selected are (a) Triple decomposition Problem (TDP) developed by Kurt, where a known element is factored into a product of three unknown factors and (b) a new version of conjugacy search that we refer from now on as Blind Conjugacy Search Problem (BCSP). Our platform structure is the general linear group GL(d,F_p) d-square non-singular matrices of prime field values. We give support to the fact that this framework is cryptographically secure against classical attacks like linear algebra attacks, length-based attacks, side-channel attacks against square (or duplicate) and multiply (or sum) algorithm, high sensitivity to pseudo random deterministic generators, etc. At same time it is immune against quantum attacks (using Grover and Shor), if the size parameters are carefully selected. Semantic security and IND-CCA2 compliance for this framework is discussed.
The article considers the Swiss model of fiscal municipalization from the ideological and methodological positions of the anthroposociocultural approach. Such components of this approach as historical and genetic methods together with the method of system-structural analysis were applied especially thoroughly and consistently. By means of them it was found that the Swiss model of fiscal decentralization is an attributive part of the construction of public power in Switzerland â municipalization from bottom to top. Special attention is drawn to defining the basic legal features of the Swiss model of fiscal municipalization. It is argued that subsidiarity does not paradigmatically coincide with decentralization: the principle of subsidiarity postulates the sovereignty of the basic territorial collectives and considers the possible conditions for its limitation for general social needs and values. On the contrary, the principle of decentralization has the national level of governance as the starting point and considers the conditions of delegation of certain tasks and competences by the state to the lower levels of public power hierarchy in the principal frames of state sovereignty. Specificity of the principle of subsidiarity in Switzerland is that cantons play dual role from the standpoint of administrative federalism. On the one hand, they are the bearers of sovereignty of public power, including taxation. On the other hand, they are the sole bearers of administrative authority and are obliged to serve national interests, that is, the needs of the entire Swiss Confederation. Paradox is that this service function of the cantons gives them considerable benefits in the inevitable opposition to the Union state, when it comes to provision of services of the entire fiscal system and the entire system of public finance.
RamĂłn Alcarria, Borja Bordel, TomĂĄs Robles, Diego R. MartĂn · 5 authors
Resource consumption in residential areas requires novel contributions in the field of consumer information management and collaborative mechanisms for the exchange of resources, in order to optimize the overall consumption of the community. We propose an authorization system to facilitate access to consumer information and resource trading, based on blockchain technology. Our proposal is oriented to the Smart communities, an evolution of Community Energy Management Systems, in which communities are involved in the monitoring and coordination of resource consumption. The proposed environment allows a more reliable management of monitoring and authorization functions, with secure data access and storage and delegation of controller functions among householders. We provide the definition of virtual assets for energy and water resource sharing as an auction, which encourages the optimization of global consumption and saves resources. The proposed solution is implemented and validated in application scenarios that demonstrate the suitability of the defined consensus mechanism, trustworthiness in the level of provided security for resource monitoring and delegation and reduction on resource consumption by the resource trading contribution.
The popularity of smart cars is increasing around the world as they offer a wide range of services and conveniences.These smart cars are equipped with a variety of sensors generating a large amount of data, many of which are sensitive. Besides, there are multiple parties involved in a lifespan of a smart car ,such as manufacturers, car owners, government agencies, and third-party service providers who also produce data about the vehicle. In addition to managing and sharing data amongst these entities in a secure and privacy-friendly way which is a great challenge itself, there exists a trust deficit about some types of data as they remain under the custody of the car owner(e.g. satellite navigation and mileage data) and can easily be manipulated. In this paper, we propose a blockchain supported architecture enabling the owner of a smart car to create an immutable record of every data, called the auto biography of a car, generated within its lifespan. We also explain how the trust about this record is guaranteed by the immutability characteristic of the blockchain. Furthermore, the paper describes how the proposed architecture enables a secure and privacy-friendly sharing of smart car data between different parties in a secure yet privacy-friendly manner.