Scalable XML Collaborative Editing with Undo short paper

Commutative Replicated Data-Type (CRDT) is a new class of algorithms that ensures scalable consistency of replicated data. It has been successfully applied to collaborative editing of texts without complex concurrency control. In this paper, we present a CRDT to edit XML data. Compared to existing approaches for XML collaborative editing, our approach is more scalable and handles all the XML editing aspects : elements, contents, attributes and undo. Indeed, undo is recognized as an important feature for collaborative editing that allows to overcome system complexity through error recovery or collaborative conflict resolution

Scalable XML Collaborative Editing with Undo

Commutative Replicated Data-Type (CRDT) is a new class of algorithms that ensure scalable consistency of replicated data. It has been successfully applied to collaborative editing of texts without complex concurrency control. In this paper, we present a CRDT to edit XML data. Compared to existing approaches for XML collaborative editing, our approach is more scalable and handles all the XML editing aspects : elements, contents, attributes and undo. Indeed, undo is recognized as an important feature for collaborative editing that allows to overcome system complexity through error recovery or collaborative conflict resolution.Le type de données répliqué commutatives (CRDT) est une nouvelle classe d'algorithmes qui assurent la cohérence des données répliquées tout en passant à l'échelle. Il a été appliqué avec succès à l'édition collaborative de textes sans mécanisme de contrôle de la concurrence complexe. Dans cet article, nous présentons un CRDT pour éditer des données XML. Par rapport aux approches existantes pour l'édition collaborative d'XML, notre approche offre un meilleur passage à l'échelle et gère tous les aspects de l'édition de document XML: éléments, le contenu, les attributs et l'annulation. En effet, l'annulation est reconnue comme un élément important pour l'édition collaborative qui permet de surmonter la complexité du système de collaboration grâce à la récupération d'erreur ou de résolution des conflits

Recréer une artillerie française en 1945 : la part belle à la récupération

En 1945, le réarmement souhaité par le gouvernement provisoire de la République française est resté inachevé. Faute des livraisons attendues et de filière industrielle fonctionnelle, seuls quelques stocks africains et la récupération de matériel adverse ont constitué une alternative. À travers l'exemple de l'artillerie, cet article montre comment la récupération s'est mise en place dès l'automne 1944, par convergence des aspirations du gouvernement provisoire et de réseaux décentralisés issus de la Résistance. Avec une ampleur inattendue, près de 350 pièces, de calibre supérieur ou égal à 75 mm, ont été réemployées avant le 8 mai 1945. Ne constituant qu'une solution temporaire, ces pièces ont néanmoins permis au gouvernement français de disposer d'une artillerie sur les fronts secondaires de l'Atlantique et des Alpes, sans trop ponctionner les ressources de la 1re armée française, dirigée vers l'Allemagne et gage du rang de la France parmi les nations victorieuses.In 1945, the rearmament sought by the provisional government of the French Republic remained unfinished. In the absence of expected deliveries and a functional industrial sector, only a few African reserves and rebuilt enemy material constituted an alternative. Through the example of artillery, this article shows how the recovery was in place from the fall of 1944, by the convergence of aspirations of the provisional government and the decentralized networks from the Resistance. At an unexpected level, nearly 350 pieces of a caliber greater than or equal to 75 mm were re-employed before May 8, 1945. Constituting only a temporary solution, these pieces nevertheless allowed the French government to have artillery on secondary fronts in the Atlantic and the Alps without draining too many resources from the 1st French army, directed toward Germany and a guarantee of France’s rank among the victorious nations

Replication-Aware Linearizability

Geo-distributed systems often replicate data at multiple locations to achieve availability and performance despite network partitions. These systems must accept updates at any replica and propagate these updates asynchronously to every other replica. Conflict-Free Replicated Data Types (CRDTs) provide a principled approach to the problem of ensuring that replicas are eventually consistent despite the asynchronous delivery of updates. We address the problem of specifying and verifying CRDTs, introducing a new correctness criterion called Replication-Aware Linearizability. This criterion is inspired by linearizability, the de-facto correctness criterion for (shared-memory) concurrent data structures. We argue that this criterion is both simple to understand, and it fits most known implementations of CRDTs. We provide a proof methodology to show that a CRDT satisfies replication-aware linearizability which we apply on a wide range of implementations. Finally, we show that our criterion can be leveraged to reason modularly about the composition of CRDTs

Logoot: a P2P collaborative editing system

Massive collaborative editing becomes a reality through leading projects such as the Wikipedia. Such massive collaboration is currently supported with costly central service. To avoid such costs, we aim to provide a peer-to-peer collaborative editing system. Existing approaches that propose distributed collaborative distributed either do not scale in term of users number or in term of editions number. We present the Logoot approach that scales in these both dimensions while ensuring causality, consistency and intention criteria. We evaluate the Logoot approach and compare it to others with a corpus of all the editions applied on a set of the most edited and biggest page of the Wikipedia

A Flexible Undo Framework for Collaborative Editing

The Undo feature has been recognized as an important feature of collaborative systems. The Operational Transformation (OT) is a suitable approach to maintain consistency of shared documents. In all existing OT undo approaches, this feature is provided by the system without a specific design. In this paper, we argue that such feature could not always achieve the user's undo intention. Therefore, we propose a new generic and flexible undo framework called ``Compensation''. This framework allows defining an adequate modification to counterbalance any action performed by any user in the collaborative system

Logoot: A Scalable Optimistic Replication Algorithm for Collaborative Editing on P2P Networks

International audienceMassive collaborative editing becomes a reality through leading projects such as Wikipedia. This massive collaboration is currently supported with a costly central service. In order to avoid such costs, we aim to provide a peer-to- peer collaborative editing system. Existing approaches to build distributed collaborative editing systems either do not scale in terms of number of users or in terms of number of edits. We present the Logoot approach that scales in these both dimensions while ensuring causality, consistency and intention preservation criteria. We evaluate the Logoot approach and compare it to others using a corpus of all the edits applied on a set of the most edited and the biggest pages of Wikipedia

Sea ice thickness and elastic properties from the analysis of multimodal guided wave propagation measured with a passive seismic array

Field data are needed for a better understanding of sea ice decline in the context of climate change. The rapid technological and methodological advances of the last decade have led to a reconsideration of seismic methods in this matter. In particular, passive seismology has filled an important gap by removing the need to use active sources. We present a seismic experiment where an array of 247 geophones was deployed on sea ice, in the Van Mijen fjord near Sveagruva (Svalbard). The array is a mix of 1C and 3C stations with sampling frequencies of 500 and 1000 Hz. They recorded continuously the ambient seismic field in sea ice between 28 February and 26 March 2019. Data also include active acquisitions on 1 and 26 March with a radar antenna, a shaker unit, impulsive sources, and artificial sources of seismic noise. This data set is of unprecedented quality regarding sea ice seismic monitoring, as it also includes thousands of microseismic events recorded each day. By combining passive seismology approaches with specific array processing methods, we demonstrate that the multimodal dispersion curves of sea ice can be calculated without an active source and then used to infer sea ice properties. We calculated an ice thickness, Young's modulus, and Poisson's ratio with values h=543 cm, E=3.90.15 GPa, and nu=0.340.02 on 1 March, and h=583 cm, E=4.4 +/- 0.15 GPa, and nu=0.32 +/- 0.02 on 5 March. These values are consistent with in situ field measurements and observations.Peer reviewe