2,342 research outputs found
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
A multi-user selective undo/redo approach for collaborative CAD systems
AbstractThe engineering design process is a creative process, and the designers must repeatedly apply Undo/Redo operations to modify CAD models to explore new solutions. Undo/Redo has become one of most important functions in interactive graphics and CAD systems. Undo/Redo in a collaborative CAD system is also very helpful for collaborative awareness among a group of cooperative designers to eliminate misunderstanding and to recover from design error. However, Undo/Redo in a collaborative CAD system is much more complicated. This is because a single erroneous operation is propagated to other remote sites, and operations are interleaved at different sites. This paper presents a multi-user selective Undo/Redo approach in full distributed collaborative CAD systems. We use site ID and State Vectors to locate the Undo/Redo target at each site. By analyzing the composition of the complex CAD model, a tree-like structure called Feature Combination Hierarchy is presented to describe the decomposition of a CAD model. Based on this structure, the dependency relationship among features is clarified. B-Rep re-evaluation is simplified with the assistance of the Feature Combination Hierarchy. It can be proven that the proposed Undo/Redo approach satisfies the intention preservation and consistency maintenance correctness criteria for collaborative systems
Implementing Performance Competitive Logical Recovery
New hardware platforms, e.g. cloud, multi-core, etc., have led to a
reconsideration of database system architecture. Our Deuteronomy project
separates transactional functionality from data management functionality,
enabling a flexible response to exploiting new platforms. This separation
requires, however, that recovery is described logically. In this paper, we
extend current recovery methods to work in this logical setting. While this is
straightforward in principle, performance is an issue. We show how ARIES style
recovery optimizations can work for logical recovery where page information is
not captured on the log. In side-by-side performance experiments using a common
log, we compare logical recovery with a state-of-the art ARIES style recovery
implementation and show that logical redo performance can be competitive.Comment: VLDB201
Autoplot: A browser for scientific data on the web
Autoplot is software developed for the Virtual Observatories in Heliophysics
to provide intelligent and automated plotting capabilities for many typical
data products that are stored in a variety of file formats or databases.
Autoplot has proven to be a flexible tool for exploring, accessing, and viewing
data resources as typically found on the web, usually in the form of a
directory containing data files with multiple parameters contained in each
file. Data from a data source is abstracted into a common internal data model
called QDataSet. Autoplot is built from individually useful components, and can
be extended and reused to create specialized data handling and analysis
applications and is being used in a variety of science visualization and
analysis applications. Although originally developed for viewing
heliophysics-related time series and spectrograms, its flexible and generic
data representation model makes it potentially useful for the Earth sciences.Comment: 16 page
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