- From: Alexandre Bertails <bertails@w3.org>
- Date: Thu, 20 Jun 2013 13:18:32 -0400
- To: Gregg Kellogg <gregg@greggkellogg.net>
- CC: Doug Schepers <schepers@w3.org>, spec-prod@w3.org, Philippe Le Hegaret <plh@w3.org>
On 06/20/2013 12:38 PM, Gregg Kellogg wrote: > On Jun 20, 2013, at 9:07 AM, Alexandre Bertails <bertails@w3.org> wrote: > >> On 06/20/2013 12:03 PM, Gregg Kellogg wrote: >>> On Jun 20, 2013, at 8:36 AM, Alexandre Bertails <bertails@w3.org> wrote: >>> >>>> On 06/20/2013 10:37 AM, Doug Schepers wrote: >>>>> Hi, folks- >>>>> >>>>> I have a suggestion for our publication workflow that I think would >>>>> provide clarity and consistency: a publication request form. >>>> >>>> Already in the pipe, partially implemented and Webmaster-only for now >>>> as development is making progress and priorities are sorted out. But >>>> that's clearly the plan for the future. >>>> >>>>> >>>>> This would be a form that contains all the fields needed for each stage >>>>> of the publication process, including spec name, shortname(s), URLs of >>>>> Editor's Draft and TR draft, abstract, WG name, WG approval to publish, >>>>> planned publication date, news-item blurb, optional list of changes, >>>>> notes (for anything out of the ordinary), etc. >>>> >>>> Believe me, you don't to fill these values by hand, it's highly >>>> error-prone. There is currently a service that "extracts" some of the >>>> informations from the spec, but it's a bit buggy and does not capture >>>> everything. The long-term alternative is to make the metadata >>>> available directly in the spec, could be generated by ReSpec and other >>>> tools directly. That's fairly easy, except for editors which must be >>>> bound to the database. This one would be easy if people can agree on >>>> using URLs to speak about the editors, though. >>> >>> If the doRDFa variable is set (to "1.1", I believe) in the respecConfig, it ends up generating good RDFa for all of this stuff in the spec. It's been optional, and only included in a couple of specs from RDF-related specs AFAIK. It seems to me that there's really no downside to making this the default (perhaps with an option to turn it off). This would make extracting such information from the specs themselves much less error prone. >> >> That's interesting. I've never looked carefully at what is generated >> by ReSpec there. Can you please point me at a recent spec embedding >> some RDFa? I can have a quick sense about how much work there would be >> to make it usable on our side. >> >> Alexandre. > > Look in the latest version of RDFa 1.1 Core, for example. For me, this yields the following: Thanks, that's already a good start. If I'm not mistaken, important information is missing though, like the type of spec (REC). Also, we'll need to find a way to have stable identifiers (URLs) for the editors. That was an issue with the previous version of tr.rdf. Alexandre. > > @prefix bibo: <http://purl.org/ontology/bibo/> . > @prefix dcterms: <http://purl.org/dc/terms/> . > @prefix foaf: <http://xmlns.com/foaf/0.1/> . > @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> . > @prefix xhv: <http://www.w3.org/1999/xhtml/vocab#> . > @prefix xsd: <http://www.w3.org/2001/XMLSchema#> . > > <> a bibo:Document; > dcterms:title "RDFa Core 1.1"; > dcterms:abstract """Abstract > The current Web is primarily made up of an enormous number of documents > that have been created using HTML. These documents contain significant > amounts of structured data, which is largely unavailable to tools and > applications. When publishers can express this data more completely, and > when tools can read it, a new world of user functionality becomes > available, letting users transfer structured data between applications > and web sites, and allowing browsing applications to improve the user > experience: an event on a web page can be directly imported into a > user's desktop calendar; a license on a document can be detected so that > users can be informed of their rights automatically; a photo's creator, > camera setting information, resolution, location and topic can be > published as easily as the original photo itself, enabling structured > search and sharing. > RDFa Core is a specification for attributes to express structured data > in any markup language. The embedded data already available in the > markup language (e.g., HTML) can often be reused by the RDFa markup, so > that publishers don't need to repeat significant data in the document > content. The underlying abstract representation is RDF [RDF-PRIMER], > which lets publishers build their own vocabulary, extend others, and > evolve their vocabulary with maximal interoperability over time. The > expressed structure is closely tied to the data, so that rendered data > can be copied and pasted along with its relevant structure. > The rules for interpreting the data are generic, so that there is no > need for different rules for different formats; this allows authors and > publishers of data to define their own formats without having to update > software, register formats via a central authority, or worry that two > formats may interfere with each other. > RDFa shares some of the same goals with microformats [MICROFORMATS]. > Whereas microformats specify both a syntax for embedding structured data > into HTML documents and a vocabulary of specific terms for each > microformat, RDFa specifies only a syntax and relies on independent > specification of terms (often called vocabularies or taxonomies) by > others. RDFa allows terms from multiple independently-developed > vocabularies to be freely intermixed and is designed such that the > language can be parsed without knowledge of the specific vocabulary > being used. > This document is a detailed syntax specification for RDFa, aimed at: > > those looking to create an RDFa Processor, and who therefore need a > detailed description of the parsing rules; > those looking to integrate RDFa into a new markup language; > those looking to recommend the use of RDFa within their > organization, and who would like to create some guidelines for their > users; > anyone familiar with RDF, and who wants to understand more about > what is happening 'under the hood', when an RDFa Processor runs. > > For those looking for an introduction to the use of RDFa and some > real-world examples, please consult the [RDFA-PRIMER]. > > How to Read this Document > First, if you are not familiar with either RDFa or RDF, and > simply want to add RDFa to your documents, then you may find the RDFa > Primer [RDFA-PRIMER] to be a better introduction. > If you are already familiar with RDFa, and you want to examine the > processing rules — perhaps to create an RDFa Processor — then you'll > find the Processing Model section of most > interest. It contains an overview of each of the processing steps, > followed by more detailed sections, one for each rule. > If you are not familiar with RDFa, but you are familiar > with RDF, then you might find reading the Syntax > > Overview useful, before looking at the Processing > > Model since it gives a range of examples of markup that use > RDFa. Seeing some examples first should make reading the processing > rules easier. > If you are not familiar with RDF, then you might want to take a look > at the section on RDF Terminology > before trying to do too much with RDFa. Although RDFa is designed to > be easy to author — and authors don't need to understand RDF to use it > — anyone writing applications that consume RDFa will need to > understand RDF. There is a lot of material about RDF on the web, and a > growing range of tools that support RDFa. This document only contains > enough background on RDF to make the goals of RDFa more clear. > RDFa is a way of expressing RDF-style > relationships using simple attributes in existing markup languages > such as HTML. RDF is fully internationalized, and permits the use of > Internationalized Resource Identifiers, or IRIs. You will see the term > 'IRI' used throughout this specification. Even if you are not familiar > with the term IRI, you probably have seen the term 'URI' or 'URL'. > IRIs are an extension of URIs that permits the use of characters > outside those of plain ASCII. RDF allows the use of these characters, > and so does RDFa. This specification has been careful to use the > correct term, IRI, to make it clear that this is the case. > Even though this specification exclusively > references IRIs, it is possible that a Host Language will > restrict the syntax for its attributes to a subset of IRIs > (e.g., @href in HTML5). Regardless of > validation constraints in Host Languages, an RDFa Processor > is capable of processing IRIs. > > """; > dcterms:issued "2012-06-07T05:00:00+0000"^^xsd:dateTime; > dcterms:language "en"; > dcterms:publisher [ a foaf:Organization; > foaf:homepage <http://www.w3.org/>; > foaf:name "World Wide Web Consortium"]; > dcterms:references <http://www.w3.org/TR/1999/REC-html401-19991224>, > <http://microformats.org>, > <http://www.w3.org/2001/tag/doc/qnameids-2004-03-17>, > <http://www.w3.org/TR/2004/REC-rdf-concepts-20040210>, > <http://www.w3.org/TR/2004/REC-rdf-primer-20040210/>, > <http://www.w3.org/TR/1999/REC-rdf-syntax-19990222>, > <http://www.w3.org/TR/2004/REC-rdf-testcases-20040210>, > <http://www.w3.org/TR/2012/NOTE-rdfa-primer-20120607>, > <http://www.w3.org/TR/2008/REC-rdfa-syntax-20081014>, > <http://standards.iso.org/ittf/PubliclyAvailableStandards/c052348_ISO_IEC_19757-2_2008(E).zip>, > <http://www.megginson.com/downloads/SAX/>, > <http://www.w3.org/TeamSubmission/turtle/>, > <http://www.w3.org/TR/2011/WD-widgets-uri-20110927>, > <http://www.w3.org/TR/2001/REC-xhtml11-20010531>, > <http://www.w3.org/TR/2002/REC-xml-exc-c14n-20020718/>, > <http://www.w3.org/TR/2008/REC-xml-20081126/>, > <http://www.w3.org/TR/2012/REC-xmlschema11-1-20120405/>; > dcterms:replaces <http://www.w3.org/TR/2012/PR-rdfa-core-20120508/>; > dcterms:requires <http://www.w3.org/TR/2009/REC-owl2-overview-20091027/>, > <http://www.w3.org/TR/2009/REC-owl2-profiles-20091027/>, > <http://www.w3.org/TR/2009/REC-owl2-rdf-based-semantics-20091027/>, > <http://www.w3.org/TR/2004/REC-rdf-mt-20040210>, > <http://www.w3.org/TR/2004/REC-rdf-syntax-grammar-20040210>, > <http://www.ietf.org/rfc/rfc2119.txt>, > <http://www.ietf.org/rfc/rfc3987.txt>, > <http://www.w3.org/TR/2012/REC-xhtml-rdfa-20120607/>, > <http://www.w3.org/TR/2009/REC-xml-names-20091208/>, > <http://www.w3.org/TR/2006/REC-xml-20060816/>, > <http://www.w3.org/TR/2012/REC-xmlschema11-2-20120405/>; > bibo:chapter <#abstract>, > <#sotd>, > <#toc>, > <#s_motivation>, > <#s_Syntax_overview>, > <#s_rdfterminology>, > <#conformance>, > <#s_syntax>, > <#s_curies>, > <#s_model>, > <#s_rdfaindetail>, > <#s_initialcontexts>, > <#s_vocab_expansion>, > <#s_datatypes>, > <#vocabulary>, > <#a_history>, > <#a_acks>, > <#references>; > bibo:editor ([ a foaf:Person; > foaf:mbox <mailto:ben@adida.net>; > foaf:name "Ben Adida"] [ a foaf:Person; > foaf:mbox <mailto:mark.birbeck@webBackplane.com>; > foaf:name "Mark Birbeck"] [ a foaf:Person; > foaf:homepage <http://blog.halindrome.com>; > foaf:mbox <mailto:shane@aptest.com>; > foaf:name "Shane McCarron"] [ a foaf:Person; > foaf:homepage <http://www.w3.org/People/Ivan/>; > foaf:mbox <mailto:ivan@w3.org>; > foaf:name "Ivan Herman"]); > bibo:subtitle "Syntax and processing rules for embedding RDF through attributes"; > xhv:license <http://www.w3.org/Consortium/Legal/ipr-notice#Copyright>; > xhv:stylesheet <http://www.w3.org/StyleSheets/TR/W3C-REC> . > > <#web-service-output-graph-preference> bibo:affirmedBy <http://www.w3.org/2010/02/rdfa/meetings/2010-07-01#resolution_1> . > > <#T-IRI-reference> a bibo:Chapter . > > <#a-description-of-rdfa-in-rdf-terms> a bibo:Chapter . > > <#a_acks> a bibo:Chapter . > > <#a_history> a bibo:Chapter; > bibo:chapter <#major-differences-with-rdfa-syntax-1.0> . > > <#abstract> a bibo:Chapter; > bibo:chapter <#how-to-read-this-document> . > > <#accessing-the-processor-graph> a bibo:Chapter; > bibo:issue [ a bibo:Issue; > bibo:affirmedBy <http://www.w3.org/2010/02/rdfa/meetings/2010-07-01#resolution_1>], > [ a bibo:Issue] . > > <#attribute_roles> a bibo:Chapter . > > <#chaining-with--property-and--typeof> a bibo:Chapter . > > <#changing-the-evaluation-context> a bibo:Chapter; > bibo:chapter <#setting-the-current-subject> . > > <#compact-uri-expressions> a bibo:Chapter . > > <#conformance> a bibo:Chapter; > bibo:chapter <#processorconf>, > <#hostlangconf>, > <#xmlrdfaconformance> . > > <#determining-the-subject-with-neither--about-nor--typeof> a bibo:Chapter; > bibo:chapter <#inheriting-subject-from--resource>, > <#inheriting-an-anonymous-subject> . > > <#evaluation-context> a bibo:Chapter . > > <#examples> a bibo:Chapter . > > <#general-use-of-curies-in-attributes> a bibo:Chapter . > > <#graphs> a bibo:Chapter . > > <#hostlangconf> a bibo:Chapter . > > <#how-to-read-this-document> a bibo:Chapter . > > <#incomplete-triples> a bibo:Chapter . > > <#informative-references> a bibo:Chapter . > > <#inheriting-an-anonymous-subject> a bibo:Chapter . > > <#inheriting-subject-from--resource> a bibo:Chapter . > > <#iri-object-resolution> a bibo:Chapter; > bibo:chapter <#using--resource-to-set-the-object>, > <#using--href-or--src-to-set-the-subject>, > <#incomplete-triples> . > > <#language-tags> a bibo:Chapter . > > <#list-generation> a bibo:Chapter . > > <#major-differences-with-rdfa-syntax-1.0> a bibo:Chapter . > > <#markup-fragments-and-rdfa> a bibo:Chapter . > > <#normative-references> a bibo:Chapter . > > <#object-resolution> a bibo:Chapter; > bibo:chapter <#object-resolution-for-the--property-attribute>, > <#iri-object-resolution> . > > <#object-resolution-for-the--property-attribute> a bibo:Chapter; > bibo:chapter <#plain-literals-1>, > <#typed-literals-1>, > <#s-xml-literals> . > > <#overview> a bibo:Chapter . > > <#plain-literals> a bibo:Chapter . > > <#plain-literals-1> a bibo:Chapter; > bibo:chapter <#language-tags> . > > <#processor-graph-reporting> a bibo:Chapter . > > <#processor-graph-terms> a bibo:Chapter . > > <#processor-status> a bibo:Chapter; > bibo:chapter <#accessing-the-processor-graph>, > <#processor-graph-terms>; > bibo:issue [ a bibo:Issue; > bibo:affirmedBy <http://www.w3.org/2010/02/rdfa/meetings/2010-07-15#resolution_1>] . > > <#processorconf> a bibo:Chapter . > > <#rdfa-attributes> a bibo:Chapter . > > <#references> a bibo:Chapter; > bibo:chapter <#normative-references>, > <#informative-references> . > > <#s-xml-literals> a bibo:Chapter . > > <#s_Completing_Incomplete_Triples> a bibo:Chapter . > > <#s_Syntax_overview> a bibo:Chapter; > bibo:chapter <#rdfa-attributes>, > <#examples> . > > <#s_blankNodes> a bibo:Chapter; > bibo:issue [ a bibo:Issue; > bibo:affirmedBy <http://www.w3.org/2010/02/rdfa/meetings/2010-10-21#resolution_3>] . > > <#s_chaining> a bibo:Chapter . > > <#s_curieprocessing> a bibo:Chapter; > bibo:chapter <#scoping-of-prefix-mappings>, > <#general-use-of-curies-in-attributes>, > <#s_terms>, > <#use-of-curies-in-specific-attributes>, > <#s_blankNodes>; > bibo:issue [ a bibo:Issue; > bibo:affirmedBy <http://www.w3.org/2010/02/rdfa/meetings/2010-07-01#resolution_3>], > [ a bibo:Issue; > bibo:affirmedBy <http://www.w3.org/2010/02/rdfa/meetings/2010-05-20#resolution_2>] . > > <#s_curies> a bibo:Chapter; > bibo:chapter <#why-curies-and-not-qnames> . > > <#s_datatypes> a bibo:Chapter; > bibo:chapter <#xml-schema-definition>, > <#xml-dtd-definition> . > > <#s_expansion_control> a bibo:Chapter; > bibo:chapter <#s_vocab_guidelines> . > > <#s_initialcontexts> a bibo:Chapter; > bibo:issue [ a bibo:Issue; > bibo:affirmedBy <http://www.w3.org/2010/02/rdfa/meetings/2010-10-21#resolution_2>], > [ a bibo:Issue; > bibo:affirmedBy <http://www.w3.org/2010/02/rdfa/meetings/2010-10-21#resolution_2>] . > > <#s_model> a bibo:Chapter; > bibo:chapter <#overview>, > <#evaluation-context>, > <#s_chaining>, > <#s_curieprocessing>, > <#s_sequence>, > <#processor-status>, > <#vocabulary-expansion> . > > <#s_motivation> a bibo:Chapter . > > <#s_rdfaindetail> a bibo:Chapter; > bibo:chapter <#changing-the-evaluation-context>, > <#s_Completing_Incomplete_Triples>, > <#object-resolution>, > <#list-generation> . > > <#s_rdfterminology> a bibo:Chapter; > bibo:chapter <#statements>, > <#triples>, > <#T-IRI-reference>, > <#plain-literals>, > <#typed-literals>, > <#turtle>, > <#graphs>, > <#compact-uri-expressions>, > <#markup-fragments-and-rdfa>, > <#a-description-of-rdfa-in-rdf-terms> . > > <#s_sequence> a bibo:Chapter; > bibo:issue [ a bibo:Issue; > bibo:affirmedBy <http://www.w3.org/2010/02/rdfa/meetings/2010-07-22#resolution_2>], > [ a bibo:Issue; > bibo:affirmedBy <http://www.w3.org/2010/02/rdfa/meetings/2010-07-22#resolution_2>], > [ a bibo:Issue; > bibo:affirmedBy <http://www.w3.org/2010/02/rdfa/meetings/2010-07-22#resolution_2>], > [ a bibo:Issue; > bibo:affirmedBy <http://www.w3.org/2010/02/rdfa/meetings/2011-01-13#ISSUE__2d_62__3a____40_prefix_processing_order>, > <http://www.w3.org/2010/02/rdfa/meetings/2011-02-14#resolution_3>, > <http://www.w3.org/2010/02/rdfa/meetings/2010-05-13#resolution_1>], > [ a bibo:Issue; > bibo:affirmedBy <http://www.w3.org/2010/02/rdfa/meetings/2010-05-13#resolution_3>], > [ a bibo:Issue; > bibo:affirmedBy <http://www.w3.org/2010/02/rdfa/meetings/2011-11-10#resolution_2>], > [ a bibo:Issue; > bibo:affirmedBy <http://www.w3.org/2010/02/rdfa/meetings/2011-11-10#resolution_2>], > [ a bibo:Issue; > bibo:affirmedBy <http://www.w3.org/2010/02/rdfa/meetings/2011-11-10#resolution_2>], > [ a bibo:Issue; > bibo:affirmedBy <http://www.w3.org/2010/02/rdfa/meetings/2011-11-10#resolution_2>], > [ a bibo:Issue; > bibo:affirmedBy <http://www.w3.org/2010/02/rdfa/meetings/2011-11-10#resolution_2>], > [ a bibo:Issue; > bibo:affirmedBy <http://www.w3.org/2010/02/rdfa/meetings/2010-06-17#resolution_2>; > bibo:issue [ a bibo:Issue; > bibo:affirmedBy <http://www.w3.org/2010/02/rdfa/meetings/2011-01-13#ISSUE__2d_60__3a__XMLLiteral_context_preservation>]], > [ a bibo:Issue; > bibo:affirmedBy <http://www.w3.org/2010/02/rdfa/meetings/2011-11-10#resolution_2>], > [ a bibo:Issue; > bibo:affirmedBy <http://www.w3.org/2010/02/rdfa/meetings/2011-11-10#resolution_2>], > [ a bibo:Issue; > bibo:affirmedBy <http://www.w3.org/2010/02/rdfa/meetings/2011-11-10#resolution_2>], > [ a bibo:Issue; > bibo:affirmedBy <http://www.w3.org/2010/02/rdfa/meetings/2010-05-13#resolution_2>] . > > <#s_syntax> a bibo:Chapter; > bibo:chapter <#attribute_roles>, > <#white_space> . > > <#s_terms> a bibo:Chapter . > > <#s_vocab_entailment> a bibo:Chapter . > > <#s_vocab_expansion> a bibo:Chapter; > bibo:chapter <#s_vocab_expansion_details>, > <#s_expansion_control> . > > <#s_vocab_expansion_details> a bibo:Chapter; > bibo:chapter <#s_vocab_entailment> . > > <#s_vocab_guidelines> a bibo:Chapter . > > <#scoping-of-prefix-mappings> a bibo:Chapter . > > <#setting-the-current-subject> a bibo:Chapter; > bibo:chapter <#the-current-document>, > <#using--about>, > <#typing-resources-with--typeof>, > <#determining-the-subject-with-neither--about-nor--typeof> . > > <#sotd> a bibo:Chapter . > > <#statements> a bibo:Chapter . > > <#term-prefix-definitions-vocabulary> a bibo:Chapter . > > <#the-current-document> a bibo:Chapter . > > <#toc> a bibo:Chapter . > > <#triples> a bibo:Chapter . > > <#turtle> a bibo:Chapter . > > <#typed-literals> a bibo:Chapter . > > <#typed-literals-1> a bibo:Chapter . > > <#typing-resources-with--typeof> a bibo:Chapter; > bibo:chapter <#chaining-with--property-and--typeof> . > > <#use-of-curies-in-specific-attributes> a bibo:Chapter . > > <#using--about> a bibo:Chapter . > > <#using--href-or--src-to-set-the-subject> a bibo:Chapter . > > <#using--resource-to-set-the-object> a bibo:Chapter . > > <#vocabulary> a bibo:Chapter; > bibo:chapter <#term-prefix-definitions-vocabulary>, > <#processor-graph-reporting>, > <#vocabulary-relationship> . > > <#vocabulary-expansion> a bibo:Chapter . > > <#vocabulary-relationship> a bibo:Chapter . > > <#white_space> a bibo:Chapter; > bibo:issue [ a bibo:Issue; > bibo:affirmedBy <http://www.w3.org/2010/02/rdfa/meetings/2010-05-20#resolution_1>] . > > <#why-curies-and-not-qnames> a bibo:Chapter . > > <#xml-dtd-definition> a bibo:Chapter . > > <#xml-schema-definition> a bibo:Chapter . > > <#xmlrdfaconformance> a bibo:Chapter . > > > Gregg > > [1] http://www.w3.org/TR/rdfa-core/ > >>> Gregg >>> >>>>> Anyone could fill out this form, though typically it would be the staff >>>>> contact's responsibility; once submitted, the publication request goes >>>>> into the DB, and emails to the appropriate people and lists (chairs >>>>> list, domain lead, staff contacts, marcomm, webreq, etc.) are sent out >>>>> automagically. >>>>> >>>>> In addition, it's queued up in a list/tool (maybe team-only, but with a >>>>> public view) that lets the domain lead and/or director click a checkbox >>>>> to approve the publication if necessary; this would also generate the >>>>> correct emails. This list would include crucial status information, to >>>>> make it easier to track what stages have been done for the publication, >>>>> and what is blocking, making it consistent and easy to review and >>>>> approve without hunting through email lists. >>>>> >>>>> Some odd cases would need to be done by regular email, of course, but >>>>> the vast majority of spec publications would be handled by this. >>>> >>>> That needs some reflection. In practice, we've seen people asking for >>>> exceptions (whether they are legitimate or not is another question :-). >>>> The system must take that into account, it's not that easy, >>>> unless we enforce the rule "no exception, follow the process". >>>> >>>>> >>>>> This would be an optional tool, though staff contacts would be >>>>> encouraged to use it; if the pub requests came through email, the staff >>>>> contact or webmaster could just make sure they are filed in this system >>>>> correctly. >>>> >>>> Someone once suggested to have a transition period (something like a >>>> year) so that existing specs can be migrated, then it would become the >>>> norm. The Webmaster's time would be more useful helping for these >>>> migrations rather than having to deal with the exceptions forever. >>>> >>>>> >>>>> This would empower WG participants, and could free up some of the more >>>>> tedious time from staff contacts. >>>> >>>> +1 oh and Webmaster's time as well, let's not forget it :-) >>>> >>>>> >>>>> This may already have been suggested elsewhere or elsewhen (I thought of >>>>> it years ago), but I think it'd be useful. >>>>> >>>>> Anyone like this idea? >>>> >>>> /me likes >>>> >>>> Alexandre. >>>> >>>>> >>>>> Regards- >>>>> -Doug >>>>> >>>>> >>>> >>>> >>> >>> >> > >
Received on Thursday, 20 June 2013 17:18:45 UTC