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1.6 Future work
Maintaining the platform: Improvements in this document are desirable to keep the benchmark results in line with
the current state of the art in compression algorithms, specially the ones fully dedicated to XML data. Additionally, as we brought the exi-ttfms up to date with 2011’s versions of
components, we encourage maintaining the platform in phase with latest versions of libraries for future usage.
Improving CPU Memory measurements for unbiased comparisons: Also, some axis of comparison between algorithm in different languages mostly C,C++
and Java are not so obvious e.g. memory foot print and will need a fresh perspective to be totally fair ask the operating system an unbiased measurement. The same remark
applies for SAX, as all algorithms do not offer a native SAX interface XML reader SAX parser.
Continuing following advances of EXI and benefits for AIXM or GML data: EXI is quite a new techno, especially for open source implementations. Right now if EXI
seems the more promising XML compression techno around, it still lacks features to be fully usable for GML data, which are by nature voluminous:
A new way to handle floating point numbers, which is compatible with deflate post-compression.
Make some drastic improvement of memory consumption and CPU needed to handle deflate post compression.
1.7 Forward
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. The Open Geospatial Consortium Inc. shall not be held
responsible for identifying any or all such patent rights.
Recipients of this document are requested to submit, with their comments, notification of any relevant patent claims or other intellectual property rights of which they may be
aware that might be infringed by any implementation of the standard set forth in this document, and to provide supporting documentation.
Copyright © 2011 Open Geospatial Consortium
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2 References
The following documents are referenced in this document. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. For
undated references, the latest edition of the normative document referred to applies.
[AIXM_XSD] AIXM 5.1 Schemas 2010-02-01 http:www.aixm.aerogallerycontentpublicAIXM51AIXM-5-1-20100201-xsd.zip
[AIXM_UML] AIXM 5.1 Conceptual Model 2010-02-01 http:www.aixm.aerogallerycontentpublicAIXM51AIXM-5-1-20100201-
webview.zip [D_NOTAM_ES] Digital NOTAM Event Specification - version 1.0 – 2011-06-08
http:www.aixm.aerogallerycontentpublicdigital_notamSpecificationsDigital20NO TAM20Event20Specification201.0.doc
[D_NOTAM_FILES] Digital NOTAM samples – version 1.0 – 2011-06-10 http:www.aixm.aerogallerycontentpublicdigital_notamSpecificationsDigital20NO
TAM20samples20-20including20Event20Schema.zip [DEF] RFC 1951 - DEFLATE Compressed Data Format Specification - version 1.3 –
1996-06 http:www.ietf.orgrfcrfc1951.txt
[FIS] X.891: Information technology - Generic applications of ASN.1: Fast infoset – 2007-01-30
http:www.itu.intrecdologin_pub.asp?lang=eid=T-REC-X.891-200505-IPDF- Etype=items
[EXI] Efficient XML Interchange EXI Format - W3C Recommendation – version 1.0 – 2011-03-10
http:www.w3.orgTR2011REC-exi-20110310 [BXML] OGC 03-002r8 - Binary-XML Encoding Specification - version 0.0.8 – 2003-05
http:www.opengis.orgtechnodiscussions03-002r8.pdf [JAPEX] JAPEX Manual - version 1.1.3 - 2007-12
http:japex.java.netdocsmanual.html [TTFMS] Efficient XML Interchange Measurements Note
http:www.w3.orgTR2007WD-exi-measurements-20070725 [TTFMS_CODE] W3C EXI Measurement Test Framework
http:www.w3.orgXMLEXIframeworkexi-ttfms.zip [IRIDIUM_SBD] Iridium’s SBD Service explained to developers
http:www.deltawavecomm.compricesIridiumTechnical20DocumentationData20 NotesIridium_SBDS_Developers_Guide.pdf
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®
Web Services Common Standard
NOTE This OWS Common Specification contains a list of normative references that are also
applicable to this Implementation Specification.
3 Terms and definitions
For the purposes of this report, the definitions specified in Clause 4 of the OWS Common Implementation Specification [OGC 06-121r3] shall apply. In addition, the following
terms and definitions apply:
3.1
Candidate In the JAPEX context, a candidate consists of an autonomous jar archive, used by the test
sequencer of JAPEX to perform benchmarking. A candidate can be seen as a couple of 2 software components linked together:
A library used to perform compression decompression of data This library can be coded using CC++ or Java, offer a SAX interface or not, be able to work on a
stream or just on a full memory buffer
An adaptation layer between Japex driver and the raw library. This layer will be in charge of converting the high level Japex solicitations like: initialize for
testing, run a test on such a topic cpu, memory,… to concrete calls to the library, using its own internal API. The adaptation layer use some code from the
platform that facilitate the declination of generic Japex driver into more compression focused specific drivers JNI, SAX,….
3.2
Platform The Efficient XML Interchange Working Group lead by W3C, develop an EXI test
platform to compare the performance of EXI against other algorithms. This platform [TTFMS_CODE] was last modified in 2007 and was reused for the present
Benchmarking of AIXM. In this context, and on for the rest of this document, Platform stands for the W3C EXI platform modified for this present AIXM Benchmark.
3.3
Compaction Measure, expressed in percentage, of the size of data output by a compression algorithm
compared to the original size of an input data.
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3.4
Data Link Any way to exchange data messages between an aircraft and the ground when aircraft is
moving on the ground or flying.
4 Conventions
4.1 Abbreviated terms
Kategori