1,720,959 research outputs found
∗.chain: Automatic coding of smart contracts and user interfaces for supply chains
No full textIn this paper we present a framework for automatically coding blockchain based supply chain management systems starting from a Domain Specific Graphical Language (DSGL) interface modeling the typical interactions of the actors of a value chain. For each asset defined in the DSGL, a solidity smart contract is created and for each interaction a specific method is defined. The DSGL allows the specification of the roles of the actors involved in the value chain, and of a set of constraints in order to permit the execution of operations on the assets only to users with specific roles. Besides the smart contracts implementing the supply chain management system, two web based user interfaces are produced by our framework for the management of the supply chain designed through the DSGL: one for the supply chain administrator and the other for the supply chain participant
A simplified method for the evaluation of inertial loads on sailing yachts
No full textThe aim of this work was to improve the understanding of dismasting, in view of the development of a new set of Rig Certification Rules specifically aimed at sailing yacht design, In the first phase of this project a preliminary systematic analysis of the dismastings of a large set of boats of different type and size has been carried out. By examining all these events, typical collapse modes have been identified, showing that whereas the traditional approach to mast scantlings is based on static loads, many of the failures took place as a result of severe dynamic loads. For this reason attention has been focused on the dynamic loads acting on the rigging caused by the response of the sailing yacht to waves. Especially in the case of boats with large displacement, these loads could be of a greater magnitude than static ones, and their evaluation must be earned out through seakeeping analysis. In particular pitching motions are extremely important, since they can cause severe accelerations to mast and rigging, possibly leading to mast collapse. Indeed dismasting is a significant event, very dangerous for the crew and very expensive to be repaired. In this paper a systematic study of the pitching behaviour of a database of sailing yachts was carried out. Using these results a simplified formulation is given to quickly evaluate the longitudinal acceleration at the mast centre of gravity. A state-of-the-art process is then used to obtain results in irregular sea states and to compute time series. Despite the small size of the database, this could be regarded as a first step towards the formulation of a simplified method based only on the boat length; this method would be able rapidly to estimate inertial loads due to waves
Simplified analytical method for the evaluation of longitudinal strength of large sailing yachts
No full textYacht manufactory industries have been faced with two different trends over the last few years: on the one hand, the current economic crisis, which has halted the production of super and mega yachts, and on the other, the increase in the dimensions of both sailing and motor yachts. In the case of sailing yachts, this trend has brought about a consequent increase in rigging proportions. Higher masts and wider sail plans have led to an enormous increase in rigging and sheet loadings. Meanwhile, speed has become an increasingly important focal point in the design process, in order to respond to market requirements; this scenario requires an acceptable compromise between structural requirements due to high rigging loads and structural weight reduction to improve the craft speed and to reduce costs and production times. For these reasons, the global strength of the hull has become a crucial aspect in the design process. Traditionally, only still water and wave bending moment in hogging and sagging conditions have been considered as global loads. For sailing yachts, however, the dock tuning bending load, which has a similar order of magnitude to the global bending moment, must be implemented in primary strength response. In this paper, the authors present a Simplified Analytical Method (S.A.M.) to estimate the longitudinal strength of a large sloop sailing yacht; this approach has been developed studying a 47-meter yacht by FE technique coupled with classic beam theory and has been verified through the analysis of other two sailing vessels of similar length. A user-friendly routine for this aim, called “StrengthCalc”, has also been create
Modeling Carne PRI supply chain with the *-Chain Platform
Full text linkCertification of the origin of products and control over the production chain are fundamental activities that can make goods competitive. Therefore, it is of great interest to develop platforms that enable domain experts to build supply chain management systems with easy-to-use systems, providing integration with structures that can guarantee the certification of a certain good. This paper shows how the*-chain framework solves this problem. In particular, we represent the use case: "Pezzata Rossa" - Carne PRI supply chain.*-chain generates the related blockchain-based traceability system. The framework's tools generate a set of solidity smart contracts implementing the system and three web interfaces to interact with them
A tool for ranking arguments through voting-games power indexes
No full textArgumentation Frameworks allow to represent sets of arguments, together with possible relations among them, in form of oriented graphs. This paper gives a short overview of a plug-in function developed for ConArg, a solver of Abstract Argumentation related problems. The web-based tool we present computes a ranking of arguments by applying different voting games power indexes, where the coalitions of individuals are defined by the extensions satisfying Dung’s semantics. At this stage of development, the tool can make use of both the Shapley Value and the Banzhaf Index
Highlighting poor anonymity and security practice in the blockchain of Bitcoin
No full textWe highlight how Bitcoin addresses are reused in transactions (implicitly or explicitly), despite recommendations and best practice strongly advise to avoid this. We analyse the blockchain with the purpose to find and count highly reused Bitcoin addresses, starting from the birth of the protocol in 2009. In this study we also include hidden addresses: these addresses are not the explicit endpoints of a transaction, but they are somehow contained in it (e.g., in the script of a Pay to Script Hash transaction). Finally, we try to de-anonymise the top-100 reused addresses, grouping and linking them to their wallet owner. This work shows that such a misuse in reusing the address often corresponds to malicious activities in the bitcoin ecosystem. These results push towards a mandatory single usage, which mitigates dangerous consequences
Real scale measurements of yacht’s mast accelerations
No full textDismasting is one of the most serious hazards for sailing boats. This event is mainly due to structural defects, poor maintenance or adverse weather conditions. For what the last aspect is concerned, it may be associated to two types of loads: the direct action of the wind on sails and accelerations caused by ship motions. The aim of this paper is to focus on the accelerations induced on the mast by ship motions using seakeeping analysis validated by real scale measurements carried out on two sailing yachts during their transfer trips from South Africa to Italy. After measurements, the recorded data have been analyzed, reordered and related to the weather conditions encountered during the transfer voyage. Then seakeeping calculations have been carried out in order to compare numerical prediction with experimental values. Finally, acceleration values to be considered for preliminary mast scantling, were derived
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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