319 research outputs found
ABCDE -- Agile Block Chain Dapp Engineering
Cryptocurrencies and their foundation technology, the Blockchain, are
reshaping finance and economics, allowing a decentralized approach enabling
trusted applications with no trusted counterpart. More recently, the Blockchain
and the programs running on it, called Smart Contracts, are also finding more
and more applications in all fields requiring trust and sound certifications.
Some people have come to the point of saying that the "Blockchain revolution"
can be compared to that of the Internet and the Web in their early days. As a
result, all software development revolving around the Blockchain technology is
growing at a staggering rate. The feeling of many software engineers about such
huge interest in Blockchain technologies is that of unruled and hurried
software development, a sort of competition on a first-come-first-served basis
which does not assure neither software quality, nor that the basic concepts of
software engineering are taken into account. This paper tries to cope with this
issue, proposing a software development process to gather the requirement,
analyze, design, develop, test and deploy Blockchain applications. The process
is based on several Agile practices, such as User Stories and iterative and
incremental development based on them. However, it makes also use of more
formal notations, such as some UML diagrams describing the design of the
system, with additions to represent specific concepts found in Blockchain
development. The method is described in good detail, and an example is given to
show how it works.Comment: 26 pages, 7 figures, 8 table
A Petri Nets Model for Blockchain Analysis
A Blockchain is a global shared infrastructure where cryptocurrency
transactions among addresses are recorded, validated and made publicly
available in a peer- to-peer network. To date the best known and important
cryptocurrency is the bitcoin. In this paper we focus on this cryptocurrency
and in particular on the modeling of the Bitcoin Blockchain by using the Petri
Nets formalism. The proposed model allows us to quickly collect information
about identities owning Bitcoin addresses and to recover measures and
statistics on the Bitcoin network. By exploiting algebraic formalism, we
reconstructed an Entities network associated to Blockchain transactions
gathering together Bitcoin addresses into the single entity holding permits to
manage Bitcoins held by those addresses. The model allows also to identify a
set of behaviours typical of Bitcoin owners, like that of using an address only
once, and to reconstruct chains for this behaviour together with the rate of
firing. Our model is highly flexible and can easily be adapted to include
different features of the Bitcoin crypto-currency system
The ICO Phenomenon and Its Relationships with Ethereum Smart Contract Environment
Initial Coin Offerings (ICO) are public offers of new cryptocurrencies in
exchange of existing ones, aimed to finance projects in the blockchain
development arena. In the last 8 months of 2017, the total amount gathered by
ICOs exceeded 4 billion US$, and overcame the venture capital funnelled toward
high tech initiatives in the same period. A high percentage of ICOS is managed
through Smart Contracts running on Ethereum blockchain, and in particular to
ERC-20 Token Standard Contract. In this work we examine 1388 ICOs, published on
December 31, 2017 on icobench.com Web site, gathering information relevant to
the assessment of their quality and software development management, including
data on their development teams. We also study, at the same date, the financial
data of 450 ICO tokens available on coinmarketcap.com Web site, among which 355
tokens are managed on Ethereum blochain. We define success criteria for the
ICOs, based on the funds actually gathered, and on the behavior of the price of
the related tokens, finding the factors that most likely influence the ICO
success likeliness
Fast wavelet transform assisted predictors of streaming time series
Abstract We explore the shift variance of the decimated, convolutional Discrete Wavelet Transform, also known as Fast Wavelet Transform. We prove a novel theorem improving the FWT algorithm and implement a new prediction method suitable to the multiresolution analysis of streaming univariate datasets using compactly supported Daubechies Wavelets. An effective real value forecast is obtained synthesizing the one step ahead crystal and performing its inverse DWT, using an integrated group of estimating machines. We call Wa.R.P. (Wavelet transform Reduced Predictor) the new prediction method. A case study, testing a cryptocurrency exchange price series, shows that the proposed system can outperform the benchmark methods in terms of forecasting accuracy achieved. This result is confirmed by further tests performed on other time series. Developed in C++, Standard 2014 conformant, the code implementing the FWT and the novel Shift Variance Theorem is available to research purposes and to build efficient industrial applications
Using an artificial financial market for assessing the impact of Tobin-like transaction taxes
The Tobin tax is a solution proposed by many economists for limiting the speculation in foreign exchange and stock markets and for making these markets stabler. In this paper we present a study on the effects of a transaction tax on one and on two related markets, using an artificial financial market based on heterogeneous agents. The microstructure of the market is composed of four kinds of traders: random traders, fundamentalists, momentum traders and contrarians, and the resources allocated to them are limited. In each market it is possible to levy a transaction tax. In the case of two markets, each trader can choose in which market to trade, and an attraction function is defined that drives their choice based on perceived profitability. We performed extensive simulations and found that the tax actually increases volatility and decreases trading volumes. These findings are discussed in the paper
Lefschetz properties and the Jacobian algebra of 3-dimensional hyperplane arrangements
In this article, we study the weak and strong Lefschetz of higher dimensional
quotients and dimension 1 almost complete intersections. We then apply the
obtained results to the study of the Jacobian algebra of hyperplane
arrangements.Comment: arXiv admin note: text overlap with arXiv:1911.04083,
arXiv:2003.0629
Un anno dopo PAAL 2008
2008-04-17Sardegna Ricerche, Edificio 2, Località Piscinamanna 09010 Pula (CA) - ItaliaPAAL 2008 - Pubblica Amministrazione Aperta e Libera: dalle tecnologie aperte alla libera circolazione dei contenuti digital
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