Cover Pages: XML Daily Newslink: Friday, 13 April 2007

A Cover Pages Publication http://xml.coverpages.org/
Provided by OASIS and Sponsor Members
Edited by Robin Cover

This issue of XML Daily Newslink is sponsored by:
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Headlines

SCA Policy Framework and WS-Policy: The Best Policy?
Semantic Interpretation for Speech Recognition (SISR) Version 1.0
Extensible Supply-chain Discovery Service Concepts
Validation Not Necessarily Harmful
Businesses Get Serious About Software as a Service
Major Search Engines Improve Sitemaps Protocol
Applied Informatics Passes Fast Infoset Interoperability Testing

SCA Policy Framework and WS-Policy: The Best Policy?
Umit Yalcinalp, SAP Blog

This article covers the synergy between the SCA Policy Framework and WS-Policy. SCA Specifications (v1.0) have been released to the public along with the announcement of intent to work on the standardization of the specifications at OASIS. Just as the industry is trying to digest the results of WS-Policy, a casual observer may wonder, why yet another framework for policy; it would be good to bring some clarification to the approach and illustrate that the specifications and the concepts are not necessarily competing for our attention and there is a synergy between the two. SCA Policy proposes abstraction and layering of policy vocabulary to existing concrete policy technologies targeted for a particular platform or stack. (1) The primary use case for SCA policy is to enable a developer to work with an abstract vocabulary by simplifying the level of understanding required to express concrete policies at service composition. This abstract vocabulary is called intents. This approach allows tooling of compositions and frees the developer from learning complicated expressions of policy. For example, a transport level confidentialy may be expressed in reality with a nested complex WS-Policy policy expression but the intent abstraction and encapsulation allows the developer to work at a high level during composition with a single keyword "confidentiality.transport". Anyone who is familiar with WS-SecurityPolicy should be aware that this shorthand is rather handy. (2) The second use case is for users who are aware of their target deployment environment. SCA Policy provides a formulation of concrete policies via a construct called policySet. A policySet in essence is a mapping between an abstract and a concrete representation of the abstract vocabulary. The content of a policySet could be a set of WS-Policy expressions. Note that for both use cases, the rubber meets the road by utilization of policySets, either during development or solely at deployment. In the end, the deployment uses the alignment of the policySets and the target policy framework for linking services and references, realizing the concrete policies deferring to the underlying framework, WS-Policy.

See also: the OSOA news story

Semantic Interpretation for Speech Recognition (SISR) Version 1.0
Luc Van Tichelen and Dave Burke (eds), W3C Technical Report

The World Wide Web Consortium has announced the release of "Semantic Interpretation for Speech Recognition (SISR) Version 1.0" as a W3C Recommendation. Part of a powerful trend towards Web access via interactive voice response, SISR tags are used to extract meaning from speech recognition. SISR defines the syntax and semantics of tag content in the Speech Recognition Grammar Specification (SRGS) for output as serialized XML or ECMAScript variables. Grammar Processors, and in particular speech recognizers, use a grammar that defines the words and sequences of words to define the input language that they can accept. The major task of a grammar processor consists of finding the sequence of words described by the grammar that (best) matches a given utterance, or to report that no such sequence exists. In an application, knowing the sequence of words that were uttered is sometimes interesting but often not the most practical way of handling the information that is present in the user utterance. What is needed is a computer processable representation of the information, the Semantic Result, more than a natural language transcript. The process of producing a Semantic Result representing the meaning of a natural language utterance is called Semantic Interpretation (SI). The Semantic Interpretation process described in this specification uses Semantic Interpretation Tags (SI Tags) to provide a means to attach instructions for the computation of such semantic results to a speech recognition grammar. When used with a Voice XML Processor, it is expected that a Semantic Interpretation Grammar Processor will convert the result generated by an SRGS speech grammar processor into an ECMAScript object.

See also: the Implementation Report

Extensible Supply-chain Discovery Service Concepts
Michael Young (ed), IETF Network Working Group Internet Draft

An new individual IETF I-D describes the concepts related to the application layer protocol called the Extensible Supply-chain Discovery Service (ESDS). The ESDS captures and queries historical events related to specific objects with attached object identifiers, such as those programmed into RFID (radio frequency identifier) tags. The interface enables disparate applications to track and trace shared life cycle views of object identifiers across a supply chain. Additionally, the ESDS provides referral services in a loosely coupled mechanism with granular security that enables selective visibility. An object identifier represents an object (or a group of objects) that exists or has previously existed within a supply chain. Each object identifier has a life cycle defined by a set of events and associated services for those events. Each event includes a timestamp that enables a historical view of events over time. The ESDS is agnostic to both the object identifier type and string syntax, thus supporting a wide base of identifier representations. An example of an object identifier could be an RFID EPC (Electronic Product Code) in EPCglobal TDT (Tag Data Translation) URI notation TDT1.0. Details and examples of the operation interface of the ESDS protocol are provided in the "Extensible Supply-chain Discovery Service Schema" document; it supplies formal syntax of the web service interface specification in Web Service Description Language (WSDL) and XML Schema (XSD). A document "Extensible Supply-chain Discovery Service Commands" describes the details of the command interface of the ESDS.

See also: the XML schema

Validation Not Necessarily Harmful
James Clark, Blog

Several months ago, Mark Baker wrote an interesting post entitled "Validation considered harmful." I agree with many of the points he makes, but I would draw different conclusions. When you take versioning into consideration, it will almost never be the case that a particular document will inherently have a single schema against which it should always be validated. A single document might be validated against: (1) Version n of a schema; (2) Version n + 1 of a schema; (3) Version n of a schema together whatever the versioning policy of version n says future versions may add; (4) What a particular implementation of version n generates; (5) What a particular implementation of version n understands; (6) The minimum constraints that a document needs in order to be processable by a particular implementation. Extensibility is also something that increases the range of possible schemas against which it may make sense to validate a document. The multiplicity of possible schemas is the strongest argument for a principle which I think is fundamental: 'Validity should be treated not as a property of a document but as a relationship between a document and a schema.' I have to disagree with the idea that you shouldn't validate what you receive. You should validate, but you need to carefully choose the schema against which you validate... The right kind of validation can make interoperability over time more robust than the alternative, simpler approach of having an implementation just ignore anything that it doesn't need. [i] Validation enables mandatory extensions. [ii] Validation by servers reduces the problems caused by broken clients; implementations accepting random junk leads inexorably to other implementations generating random junk. By making appropriate use of XML namespaces, I believe it's possible to design language evolution policies that are both loose enough not to unduly constrain future versions and strict enough that a useful proportion of client errors can be detected. I think Atom is a good example.

Businesses Get Serious About Software as a Service
Mary Weier and Lisa Smith, DDJ

Two out of three businesses are either buying or considering buying software via a subscription model, according to a recent InformationWeek Research survey. That's put pressure on the big software vendors, prompting them to offer SaaS models or at least give lip service to the idea. Microsoft and SAP are among the companies developing more subscription offerings for customers, and Oracle president Charles Phillips is giving a presentation in New York this week on how its subscription software can lower customers' costs. SaaS is one of those technology delivery trends that will come from the bottom up; small and midsize companies will adopt it faster, according to Ken Harris, CIO at Shaklee, a $500 million-a-year supplier of nutritional supplements, makeup, and other products. Shaklee began moving its IT infrastructure to a service-oriented architecture two years ago, and subscription software fits perfectly into that plan. Shaklee had RightNow Technologies marketing and CRM software running within 120 days, spending in the six-figure range, he says. Similar projects at other companies where Harris was CIO cost millions of dollars and took 12 to 18 months using traditional CRM vendors. As early adopters are showing, SaaS is no longer a niche approach to software delivery. Security, reliability, and integration remain concerns, but not enough to outweigh the implementation and cost benefits for many. The true test will be whether companies can use SaaS effectively for business-critical applications.

Major Search Engines Improve Sitemaps Protocol
Juan Carlos Perez, ComputerWorld

The rare collaboration between search rivals Google Inc., Yahoo Inc. and Microsoft Corp. over site maps has yielded its first result. The vendors announced they have enhanced Sitemap, a protocol designed to simplify how webmasters and online publishers submit their sites' content for indexing in search engines. Along with the improvements, the vendors also announced that IAC/InterActiveCorp's Ask.com will support the protocol, which thus gains backing from another major search engine operator. IBM also signed up to support the effort. In November [2006], Google, Yahoo and Microsoft agreed to support Sitemap, an open-source protocol based on XML. A site map is a file that webmasters and publishers put on their sites to help the search engines' automated Web crawlers properly index Web pages. The Sitemap protocol aims to provide a standard format for site maps, which should simplify their creation by Web publishers and their discovery and interpretation by search engines. The Sitemap protocol, now in Version 0.90, now provides a uniform way of telling search index crawlers where site map files are located on a site. All Web crawlers recognize the robots.txt instruction, which tells crawlers not to index certain information, so now webmasters can indicate the location of their site map file within 'robots.txt' files.

See also: Sitemaps XML Format

Applied Informatics Passes Fast Infoset Interoperability Testing
Staff, Applied Informatics

Applied Informatics Software Engineering GmbH has announced successful completion of interoperability testing its POCO C++ Fast Infoset implementation as a participant in Sun's Fast Infoset Interoperability Project. Fast Infoset support is now available and interoperable on a variety of programming languages and platforms, including C++ on Windows and Unix platforms, Java and .NET. Fast Infoset is an ITU-T and ISO defined standard that specifies a binary encoding for W3C XML Information Set. Unlike other XML representations, the Fast Infoset standard has the dual benefits of both compression and performance, making it the ideal choice for moving large XML data between disparate low bandwidth systems or for high performance systems such as those utilising Web services. Applied Informatics provides a cross platform C++ implementation of the Fast Infoset standard as part of its POCO C++ Libraries. The POCO Fast Infoset library is available in source code form for many platforms, including Windows, Unix, Linux, Mac OS X, and QNX. POCO, the C++ Portable Components is a collection of open source C++ class libraries that simplify and accelerate the development of network-centric, portable applications in C++. Their modular and efficient design and implementation makes the C++ Portable Components extremely well suited for embedded development.


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