17,175 research outputs found
XML Compression via DAGs
Unranked trees can be represented using their minimal dag (directed acyclic
graph). For XML this achieves high compression ratios due to their repetitive
mark up. Unranked trees are often represented through first child/next sibling
(fcns) encoded binary trees. We study the difference in size (= number of
edges) of minimal dag versus minimal dag of the fcns encoded binary tree. One
main finding is that the size of the dag of the binary tree can never be
smaller than the square root of the size of the minimal dag, and that there are
examples that match this bound. We introduce a new combined structure, the
hybrid dag, which is guaranteed to be smaller than (or equal in size to) both
dags. Interestingly, we find through experiments that last child/previous
sibling encodings are much better for XML compression via dags, than fcns
encodings. We determine the average sizes of unranked and binary dags over a
given set of labels (under uniform distribution) in terms of their exact
generating functions, and in terms of their asymptotical behavior.Comment: A short version of this paper appeared in the Proceedings of ICDT
201
Generating Concise and Readable Summaries of XML Documents
XML has become the de-facto standard for data representation and exchange,
resulting in large scale repositories and warehouses of XML data. In order for
users to understand and explore these large collections, a summarized, bird's
eye view of the available data is a necessity. In this paper, we are interested
in semantic XML document summaries which present the "important" information
available in an XML document to the user. In the best case, such a summary is a
concise replacement for the original document itself. At the other extreme, it
should at least help the user make an informed choice as to the relevance of
the document to his needs. In this paper, we address the two main issues which
arise in producing such meaningful and concise summaries: i) which tags or text
units are important and should be included in the summary, ii) how to generate
summaries of different sizes.%for different memory budgets. We conduct user
studies with different real-life datasets and show that our methods are useful
and effective in practice
The lifecycle of provenance metadata and its associated challenges and opportunities
This chapter outlines some of the challenges and opportunities associated
with adopting provenance principles and standards in a variety of disciplines,
including data publication and reuse, and information sciences
Automating property-based testing of evolving web services
Web services are the most widely used service technology that drives the Service-Oriented Computing~(SOC) paradigm. As a result, effective testing of web services is getting increasingly important. In this paper, we present a framework and toolset for testing web services and for evolving test code in sync with the evolution of web services. Our approach to testing web services is based on the Erlang programming language and QuviQ QuickCheck, a property-based testing tool written in Erlang, and our support for test code evolution is added to Wrangler, the Erlang refactoring tool.
The key components of our system include the automatic generation of initial test code, the inference of web service interface changes between versions, the provision of a number of domain specific refactorings and the automatic generation of refactoring scripts for evolving the test code. Our framework provides users with a powerful and expressive web service testing framework, while minimising users' effort in creating, maintaining and evolving the test model. The framework presented in this paper can be used by both web service providers and consumers, and can be used to test web services written in whatever language; the approach advocated here could also be adopted in other property-based testing frameworks and refactoring tools
XML Schema-based Minification for Communication of Security Information and Event Management (SIEM) Systems in Cloud Environments
XML-based communication governs most of today's systems communication, due to
its capability of representing complex structural and hierarchical data.
However, XML document structure is considered a huge and bulky data that can be
reduced to minimize bandwidth usage, transmission time, and maximize
performance. This contributes to a more efficient and utilized resource usage.
In cloud environments, this affects the amount of money the consumer pays.
Several techniques are used to achieve this goal. This paper discusses these
techniques and proposes a new XML Schema-based Minification technique. The
proposed technique works on XML Structure reduction using minification. The
proposed technique provides a separation between the meaningful names and the
underlying minified names, which enhances software/code readability. This
technique is applied to Intrusion Detection Message Exchange Format (IDMEF)
messages, as part of Security Information and Event Management (SIEM) system
communication hosted on Microsoft Azure Cloud. Test results show message size
reduction ranging from 8.15% to 50.34% in the raw message, without using
time-consuming compression techniques. Adding GZip compression to the proposed
technique produces 66.1% shorter message size compared to original XML
messages.Comment: XML, JSON, Minification, XML Schema, Cloud, Log, Communication,
Compression, XMill, GZip, Code Generation, Code Readability, 9 pages, 12
figures, 5 tables, Journal Articl
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