A Formal Account of the Open Provenance Model

On the Web, where resources such as documents and data are published, shared, transformed, and republished, provenance is a crucial piece of metadata that would allow users to place their trust in the resources they access. The Open Provenance Model (OPM) is a community data model for provenance that is designed to facilitate the meaningful interchange of provenance information between systems. Underpinning OPM is a notion of directed graph, where nodes represent data products and processes involved in past computations, and edges represent dependencies between them; it is complemented by graphical inference rules allowing new dependencies to be derived. Until now, however, the OPM model was a purely syntactical endeavor. The present paper extends OPM graphs with an explicit distinction between precise and imprecise edges. Then a formal semantics for the thus enriched OPM graphs is proposed, by viewing OPM graphs as temporal theories on the temporal events represented in the graph. The original OPM inference rules are scrutinized in view of the semantics and found to be sound but incomplete. An extended set of graphical rules is provided and proved to be complete for inference. The paper concludes with applications of the formal semantics to inferencing in OPM graphs, operators on OPM graphs, and a formal notion of refinement among OPM graphs

A formal model of provenance in distributed systems

We present a formalism for provenance in distributed systems based on the π-calculus. Its main feature is that all data products are annotated with metadata representing their provenance. The calculus is given a provenance tracking semantics, which ensures that data provenance is updated as the computation proceeds. The calculus also enjoys a pattern-restricted input primitive which allows processes to decide what data to receive and what branch of computation to proceed with based on the provenance information of data. We give examples to illustrate the use of the calculus and discuss some of the semantic properties of our provenance notion. We conclude by reviewing related work and discussing directions for future research.peer-reviewe

BlocKit:A physical kit for materializing and designing for blockchain infrastructure

Blockchain is a disruptive technology which has significantly challenged assumptions that underpin financial institutions, and has provoked innovation strategies that have the potential to change many aspects of the digital economy. However, because of its novelty and complexity, mental models of blockchain technology are difficult to acquire. Building on embodied cognition theories and material centered-design, we report an innovative approach for the design of BlocKit, a physical three-dimensional kit for materializing blockchain infrastructure and its key entities. Through an engagement with different materials such as clay, paper, or transparent containers we identified important properties of these entities and materialized them through physical artifacts. BlocKit was evaluated by 15 blockchain experts with findings indicating its value for experts’ high level of engagement in communicating about, and designing for blockchain infrastructure. Our study advances an innovative approach for the design of such kits, an initial vocabulary to talk about them, and design implications intended to inspire HCI researchers to engage in designing for infrastructures

La notion de privilège en droit romain et en droit civil français ; étude historique et critique

"Bibliographie": p. [337]-344Mode of access: Internet

Vistas fiscales del adjunto al señor fiscal de la excelentísima Corte Suprema /

Author's inscribed presentation copy to Sr. Dr. D. Man.l A. Calderón.Mode of access: Internet

Acts of Assembly, passed in the Island of Nevis, from 1664 to 1739, inclusive

Includes: An abridgment of the Acts of Assembly, passed in the Island of Nevis, from 1664 to 1739, inclusive. London : Printed by J. Baskett, 1740 (p. [143]-168)Head and tail pieces; printer's ornamentsMode of access: Internet.From the Charles F. Heartman collection of material relating to negro culture: book lable in original coverBook-plate of Swynfen Jervis of the Inner-Temple, esqr., on verso of title-pag

Das Fideikommiss-Recht nach dem Oest. allg. b. Gesetz-Buche und mehr als zweihundert darauf bezüglichen besonderen Anordnungen

Mode of access: Internet