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edumatters: retracting claims about a maintained flag.


1 msdemlei 3956 \documentclass{ivoa}
2     \input tthdefs
3 marco.merot@gmail.com 2311
4 msdemlei 3956 \usepackage{todonotes}
5     \usepackage{listings}
6 msdemlei 3960 \lstloadlanguages{XML,sh,SQL}
7 msdemlei 3956 \lstset{flexiblecolumns=true,tagstyle=\ttfamily, showstringspaces=False}
8 volute@g-vo.org 2412
9 msdemlei 3956 \ivoagroup{Edu IG}
10 marco.merot@gmail.com 2311
11 msdemlei 3956 \author{Molinaro, M.}
12     \author{Demleitner, M.}
13     \author{Ramella, M.}
14     \author{Iafrate, G.}
15 volute@g-vo.org 2302
16 msdemlei 3956 \editor{Molinaro, M.}
17    
18 msdemlei 3959 \SVN$Rev$
19     \SVN$Date$
20     \SVN$URL$
21    
22 msdemlei 3956 \previousversion{First published version}
23    
24    
25     \title{Educational Resources in the Virtual Observatory}
26    
27     \begin{document}
28    
29     \begin{abstract}
30    
31 volute@g-vo.org 2410 The goal of this IVOA Note is to introduce and explain practices followed
32     and requirements found while creating and
33     deploying astrophysical resources
34 msdemlei 3957 dedicated to educational purposes ranging from pre-school outreach
35     material to courseware intended for active researchers
36     within the standard VO framework.
37 marco.merot@gmail.com 2307 Issues, proposed solutions and desirables are here reported to be
38     possibly taken into account in future modifications of relevant
39     standards.
40    
41 volute@g-vo.org 2410
42 marco.merot@gmail.com 2307
43 msdemlei 3956 \end{abstract}
44 volute@g-vo.org 2304
45 msdemlei 3956
46     \section{Introduction}
47    
48 marco.merot@gmail.com 2307 Advances in technology and communications are creating new and exciting
49 volute@g-vo.org 2410 opportunities for teachers to bring astronomy into their
50     classrooms. As the VO makes science-grade data publicly available and
51     classroom sets of (suitably) networked PCs are now standard in schools,
52 msdemlei 3957 exciting projects come within reach of teachers. In order to make things
53     happen, it is important to disseminate material to help teachers
54 volute@g-vo.org 2410 tap into these resources. These include documented step-by-step
55 marco.merot@gmail.com 2429 tutorials, use cases explaining how to perform basic astrophysical research
56 volute@g-vo.org 2410 using VO tools and resources, and similar exist in various formats and
57     have been translated in different languages.
58    
59 msdemlei 3957 At the same time, the VO as used in research is a complex tool,
60     introducing many novel techniques. To enable university level students
61     and active researchers to fully exploit the VO's capabilities, course
62     materials and worked-out use-cases have been found an efficient means of
63     developing the necessary skills far beyond interactive course situations
64     like ``VO Days''. Efficient ways for interested users to locate such
65     material as well as for VO operators to curate it are highly desirable.
66 msdemlei 3956
67     New opportunities also come on the observational side.
68 volute@g-vo.org 2410 There is a growing availability of remotely controlled
69 marco.merot@gmail.com 2307 telescopes dedicated to education in many countries world-wide, from the
70 msdemlei 3957 Bradford Robotic Telescope\footnote{\url{http://www.telescope.org}} on Mount
71     Teide, Tenerife
72 msdemlei 3956 to the radio telescopes of the Radio Physics
73 msdemlei 3957 Lab\footnote{\url{http://www.ncra.tifr.res.in/rpl}}, IUCAA, Pune.
74     In some cases, educational telescopes are
75 marco.merot@gmail.com 2307 linked into a network with the aim of guaranteeing the best observing conditions,
76     including deep sky observations during regular daytime school hours, and
77     the best instrument for the particular program of interest. Examples
78 msdemlei 3956 of these networks are
79     iTelescope.net\footnote{\url{http://www.itelescope.net}} and
80     EuHOU-MW\footnote{\url{http://euhou.obspm.fr/public}}.
81    
82    
83    
84 marco.merot@gmail.com 2307 As telescopes enter classrooms more frequently, interest is growing for a
85     public archive of observations and hence for publishing and curation tools,
86     together with the basic applications needed to retrieve, display
87     and analyze data. The VO already includes most of the technology needed
88     to satisfy the requests of educational observatories. In fact, since several
89     years, VO, and in particular the European project EuroVO, is devoting part
90 msdemlei 3956 of its resources to
91     education\footnote{\url{http://wwwas.oats.inaf.it/aidawp5}}. It is
92 marco.merot@gmail.com 2307 therefore a natural decision for VO to tackle the problem of publishing
93     educational data in VO archives.
94 volute@g-vo.org 2410
95 msdemlei 3956
96     Resource registration for both educational data services and documents
97 marco.merot@gmail.com 2429 is the most appropriate approach toward making educational resources
98     available within the VO. While
99     technically this may seem trivial, keeping too technical
100 volute@g-vo.org 2410 research services out of the the resources devoted to education will
101 marco.merot@gmail.com 2429 require some effort, that will also be needed in order to avoid contaminating
102 msdemlei 3956 VO professional research with obviously inadequate material.
103 volute@g-vo.org 2410
104 msdemlei 3956 In the next section we discuss the idea of educational resources curation, then
105     we work out the use cases and needs for
106 marco.merot@gmail.com 2429 registration of tutorials and documents. Finally, we discuss the idea of introducing language
107     internationalization in the resources.
108 volute@g-vo.org 2304
109 msdemlei 3956
110    
111     \section{A Curated Registry for Education}
112    
113     \label{sect:curreg}
114    
115    
116 volute@g-vo.org 2410 From a technical point of view the registration of educational services
117     does not require extensions
118 msdemlei 3956 to the existing for VOResource standard \citep{2008ivoa.spec.0222P}.
119 volute@g-vo.org 2410 The only real need for investigating changes to what already exists is due to a
120 marco.merot@gmail.com 2307 use case's distinction between resources to be used in teaching and dissemination
121     versus all the research driven resources that exist in the VO.
122 msdemlei 3956
123    
124    
125 marco.merot@gmail.com 2429 For simplicity here we will distinguish these two groups of resources as
126 msdemlei 3956 \emph{educational}
127     and
128     \emph{professional}
129     but without any intent of putting them
130 marco.merot@gmail.com 2307 on different levels of importance.
131    
132    
133 msdemlei 3956
134     \subsection{Educational vs. Professional Resources}
135    
136     \label{sect:eduvspro}
137    
138    
139     On the one side, teachers and educators may find it difficult to filter out
140     from all VO resources those that are suitable for their tutorials and
141     examples. On the other side, educational resources should not be retrieved
142     by a standard professional query.
143     Given that it is not a matter of data quality, but only a distinction upon
144     the resources' scope, nevertheless this duality leads to an issue about the
145     proper way to tag resources for educational usage.
146    
147    
148    
149     In the next subsection we propose a possible tagging solution, based upon
150     the existing
151     \vorent{ContentLevel}
152     element of VOResource, but requiring a small change
153     to it. The subsequent subsection describes the idea of a
154     curated registry for educational resources and the reasons for it to exist.
155    
156    
157    
158     \subsection{ContentLevel granularity issue}
159    
160     \label{sect:contentlvl}
161    
162 msdemlei 3957 VOResource already has the
163 msdemlei 3956 \vorent{ContentLevel}
164     element
165     allowing data publishers to optionally identify their resources as being
166     suitable for one or more of the following audiences:
167    
168    
169     \begin{itemize}
170    
171     \item General{}
172    
173     \item Elementary Education{}
174    
175     \item Middle School Education{}
176    
177     \item Secondary Education{}
178    
179     \item Community College{}
180    
181     \item University{}
182    
183     \item Research{}
184    
185     \item Amateur{}
186    
187     \item Informal Education{}
188    
189     \end{itemize}
190    
191     This element turns out to be misused by many publishers, presumably because
192     it is not really clear what the subtle differences between the available
193     possibilities are; also, to require a fairly substantial enumeration to
194     convey ``for school use'' seems, in retrospect, not likely to promote
195     widespread adoption. We hence propose to simplify the content model
196     to:
197    
198    
199     \begin{itemize}
200    
201     \item General{}
202    
203     \item Research{}
204    
205     \item Amateur{}
206    
207     \end{itemize}
208    
209     We expect this to reach two goals:
210    
211     \begin{itemize}
212    
213     \item to make publishers to better describe (on the average)
214     their resources{}
215    
216     \item to providing a tagging solution that suits a first filtering
217     on the resources at client level{}
218    
219     \end{itemize}
220    
221     Of course, the chance to
222     add an
223     \emph{Educational}
224     value option to this shrinked list, or even
225     substitute it to the
226     \emph{General}
227     one, would be a valuable change.
228    
229    
230    
231     This change in the already existing standard will require only
232     a small effort to update already registered resources because nearly 97\% of
233     them currently have \vorent{ContentLevel} set to
234     \emph{research}, about 2\% of them have
235     no \vorent{ContentLevel} defined at all and only the remaining have a different value
236     (or set of values) set for this element (Appendix \ref{app:clcurrval} details better these
237     figures).
238    
239    
240     Until the change in VOResource can be performed, it
241     can work as a ``best practice'' recommendation, possibly even at a
242     registry level, where registries can map existing
243     \vorent{ContentLevel} values
244     of
245     \emph{University}
246     to
247     \emph{Research}
248     and
249     everything else except
250     \emph{Amateur}
251     to
252     \emph{General}.
253     .
254    
255    
256     \subsection{Curating the Edu Registry}
257    
258     \label{sect:edureg}
259    
260    
261     Even in the case of the simplified
262     \vorent{ContentLevel}
263     tagging system
264     a curated registry for educational VO resources will be useful for
265     educators in order to let their students work with a registry without having to
266     worry about confusing material or overwhelming data sizes. A good example
267     for this is the educational version of the Aladin sky atlas that has a
268     built in, curated set of resources suitable for educational level
269     tutorials.
270    
271    
272    
273     Curation will require some effort in managing and keeping up to date
274     such a registry but, most important, it is subjected to some restrictions coming from
275     the IVOA resource registry architecture.
276    
277    
278    
279 msdemlei 3957 If such a registry were a standard publishing registry as laid down in
280     Registry Interfaces
281     \citep{2009ivoa.spec.1104B},
282 msdemlei 3956 its resources would be harvested by the full registries: this means
283     that any dedicated educational resource would end up in the full VO
284     set of resources. For reasons mentioned above, this is not
285     desirable.
286    
287    
288     If it were to be a full registry, it will harvest itself all the existing
289     resources, and not all of them will fit, or be suitable for, the educational
290     scope the registry has to be preserved for.
291    
292    
293    
294 msdemlei 3957 We need a resource (the curated, in Registry Interfaces
295 msdemlei 3956 parlance, local, registry) capable of:
296    
297     \begin{itemize}
298    
299     \item
300     \emph{selectively}
301     harvesting the existing VO resources
302 msdemlei 3957 (e.g., from a full registry);{}
303 msdemlei 3956
304     \item register its own educational resources without being directly
305 msdemlei 3957 harvested by full registries (e.g., this could be done using a
306 marco.merot@gmail.com 2307 sibling publishing registry dedicated to host those educational
307 msdemlei 3956 resources that are to be harvested by the standard full registries.{}
308    
309     \end{itemize}
310    
311     This solution, also presented in Fig. 1, will not touch the existing architecture
312     while giving flexibility for the emerging educational resources to
313     be curated.
314    
315    
316    
317     \begin{figure}
318    
319     \includegraphics[width=0.9\textwidth]{curation.png}
320     \caption{Graphic illustration
321 marco.merot@gmail.com 2415 of the connecting interfaces between full registries and the educational
322 msdemlei 3956 curated one. The
323     \emph{auxiliary}
324     publishing is the only automatic token
325     from the edu part.}
326     \label{fig:curation}
327     \end{figure}
328 marco.merot@gmail.com 2307
329 msdemlei 3956 \section{Registering Texts}
330 volute@g-vo.org 2304
331 msdemlei 3956 \label{sect:regext}
332    
333     Educational material is not only about services – text-like material
334 marco.merot@gmail.com 2429 like tutorials, worked-out use cases, or textbook-like material are at
335 volute@g-vo.org 2304 least as important. Within the VO community, there is a large body of
336 marco.merot@gmail.com 2429 educational material for a wide variety of audiences ranging from pre-school to
337 marco.merot@gmail.com 2415 researchers:
338 volute@g-vo.org 2304
339 msdemlei 3956 \begin{itemize}
340    
341 msdemlei 4010 \item EURO-VO AIDA WP5 -- \url{http://wwwas.oats.inaf.it/aidawp5/eng_download.html}
342 msdemlei 3956
343 msdemlei 4010 \item EURO-VO Scientific Tutorials -- \url{http://www.euro-vo.org/?q=science/scientific-tutorials}
344 msdemlei 3956
345 msdemlei 4010 \item GAVO tutorials --
346     \url{http://www.g-vo.org/pmwiki/Documents/Tutorials}
347 msdemlei 3956
348 msdemlei 4010 \item CDS tutorials -- \url{http://cdsweb.u-strasbg.fr/tutorials/}
349 msdemlei 3956 \end{itemize}
350    
351    
352     To date, such material has been collected informally by the various
353 marco.merot@gmail.com 2429 projects on plain web pages. It is, in consequence, hard to find, with
354 msdemlei 4010 knowledge of its existence often passed on antecdotically. In order to improve upon
355 marco.merot@gmail.com 2429 this situation, we
356 msdemlei 4010 propose to keep record of educational material in the VO Registry.
357 volute@g-vo.org 2304
358 msdemlei 3956 The VO already has a registry extension for standards, which of
359 msdemlei 3957 course are also text-like, StandardsRegExt \citep{2012ivoa.spec.0508H}. This extension,
360 volute@g-vo.org 2412 however, focuses on metadata important for standards – e.g.,
361     vocabularies and status – that is not pertinent for educational
362 volute@g-vo.org 2304 material. Conversely, it is not concerned with document language (which
363     can safely be assumed to be English for standards), and it disregards
364 msdemlei 3957 the issue of locating formatted and source versions, which for educational
365 msdemlei 4010 material is important.
366 volute@g-vo.org 2304
367 msdemlei 4010 Therefore, we believe text-like material should be described in a
368     registry extension of its own: DocRegExt.
369 volute@g-vo.org 2410
370 msdemlei 4010
371 msdemlei 3956 \subsection{Use Cases}
372 volute@g-vo.org 2304
373 msdemlei 3956 \label{sect:regext-usecases}
374 volute@g-vo.org 2304
375 msdemlei 3956 The design of DocRegExt has been guided by the desire to fulfill the
376 msdemlei 3958 following discovery cases:
377 msdemlei 3956
378    
379     \begin{itemize}
380    
381     \item Is there a tutorial covering discovering intermediate mass black
382     holes? (Standard VOResource is sufficient){}
383    
384     \item Is there a tutorial covering working with X-Ray data? (Standard
385     VOResource is sufficient){}
386    
387 msdemlei 4010 \item Is there a tutorial dealing with planets suitable for school use?
388 msdemlei 3956 (Standard VOResource is sufficient){}
389    
390 msdemlei 4010 \item Is there a tutorial dealing with planets suitable for school use in
391 msdemlei 3956 Italian? (That requires the declaration of the document language){}
392    
393     \item What are the subjects of maintained (in the sense of: probably
394 volute@g-vo.org 2304 working in the VO as found by the students) tutorials?
395     (The active flag of standard VOResource is
396     unsuitable here since even outdated resources will still be accessible;
397 msdemlei 4011 we have to get a better idea of how a tutorial would transition into
398     unmaintained before this use case can actually be supported)
399 msdemlei 3956
400     \item Are there tutorials using redshifts? (This is solved by allowing
401     table metadata in DocRegExt){}
402    
403     \item Where can I find an editable version of tutorial ivo://auth/tut1?
404 volute@g-vo.org 2304 (This is solved by allowing multiple access URLs with different content
405 msdemlei 3956 types, which should be sufficient to allow answering the question){}
406    
407     \item Are there translations of tutorial ivo://auth/tut2? (This is covered
408 volute@g-vo.org 2304 by the recommendations on declaring relationships between text-like
409 msdemlei 3956 resources){}
410    
411     \item Is there material using service ivo://auth/svc1? (Again, declaring
412     relationships covers this use case){}
413    
414     \item Is there material about something visible tonight? (In principle,
415 msdemlei 3957 allowing the coverage element withing DocRegExt resources enables this
416     use case, although as of this writing, the Registry infrastructure does
417     not support spatial discovery).
418 msdemlei 3956
419 msdemlei 3957 \item I found this VO tutorial somewhere on the net (``on a mirror''). Is it
420 volute@g-vo.org 2410 the latest version? If not, where can I find an update? (Unless the
421 msdemlei 3956 title of the text changed, standard VOResource should suffice){}
422 volute@g-vo.org 2304
423 msdemlei 3956 \end{itemize}
424    
425 msdemlei 3958 An important additional use case is enabling an attractive, browsable
426 msdemlei 4010 list of registred educational material. A first attempt at such a
427 msdemlei 3958 service is GAVO's VO Text Treasures (VOTT)
428     service\footnote{\url{http://dc.g-vo.org/VOTT}}. It was found that one
429     requirement resulting from this use case is direct access to formatted
430     material in order to enable thumbnail generation.
431    
432 msdemlei 3956 On the use cases of locating editable forms of such texts – which
433 volute@g-vo.org 2412 has been found to be necessary fairly regularly – we note in passing
434 volute@g-vo.org 2410 that representing source-product relationships is in principle in the
435 msdemlei 3957 domain of provenance and thus not in the Registry's main scope. However, in
436 volute@g-vo.org 2410 the case discussed here the relation is so simple and its representation
437 msdemlei 3956 so useful that we propose to include it in a DocRegExt.
438 volute@g-vo.org 2410
439 msdemlei 3956 \subsection{A Document Registry Extension}
440 volute@g-vo.org 2412
441 msdemlei 4010 %% NOTE: When you change the schema, make Markus run a
442     %% make install-schema
443     %% to update the current "canonical" schema location.
444    
445 msdemlei 3956 \label{sect:regext-ext}
446 volute@g-vo.org 2412
447 msdemlei 3960 To satisfy the requirements derived above, we have designed a registry extension with
448 msdemlei 4010 two definitions.
449     To avoid unnecessary incompatibilities when migrating to a proper IVOA
450     standard, we use the namespace URI
451    
452     $$\hbox{\nolinkurl{http://www.ivoa.net/xml/DocRegExt-1.xsd}}$$
453    
454     for DocRegExt even while the schema cannot actually retrieved from
455     there. The canonical schema location until the extension is endorsed by
456     the IVOA is \url{http://docs.g-vo.org/xml/DocRegExt-1.xsd}.
457    
458     The recommended schema prefix for DocRegExt is \texttt{doc}.
459    
460     To let authors define comprehensive metadata, the schema
461     re-uses the \vorent{vs:CatalogService} type
462 msdemlei 3960 from VODataService 1.1 \citep{2010ivoa.spec.1202P} to construct
463 msdemlei 4010 the \vorent{doc:Document} resource type.
464 volute@g-vo.org 2412
465 msdemlei 3958 While the schema does not limit what kinds of capabilities a
466     \vorent{doc:Document} record has -- it is conceivable that tailored
467 msdemlei 3960 services are communicated in this way --, access to actual files is
468     enabled using \vorent{doc:Edition}-typed capabilities. It may be
469 msdemlei 3958 argued that this use of VOResource capabilities stretches their
470     semantics a bit. We argue, however, that these documents can well be
471     understood as parameterless service endpoints. Using capabilities
472     furthermore allows a complete representation of the metadata in RegTAP
473     without any extra tables (cf.~sect.~\ref{sect:docregext-regtap}).
474 volute@g-vo.org 2412
475 msdemlei 3958 The resource-level reference URL in \vorent{doc:Document} records should
476     be some sort of landing page with an abstract of the text and links to
477     the full texts and perhaps the document source(s). When using the
478     versioned repository (sect.~\ref{sect:svn-repo}), this could be the
479     top-level README file within the VCS. For simple documents, it is
480     acceptable to use the English-language document itself as
481     \vorent{referenceURL}; documents only available in non-English should
482     provide a landing page with an English-language abstract, though.
483 volute@g-vo.org 2412
484 msdemlei 3960 The \vorent{facility} and \vorent{instrument} items should only be set
485     if the text in question actually exploits particular properties of the
486     concrete instrument. A \vorent{tableset} can be given for the central
487     table-like structures a text deals with and facilitates discovery by
488     physics via the UCDs given in the tableset.
489    
490 msdemlei 3956 Document-typed resource records should define relations to other
491 msdemlei 3960 general resources (e.g., applications, services,\dots)
492 msdemlei 3958 they use. VOResource 1.1 provides a vocabulary of possible
493 msdemlei 3960 relationships. Document records should preferably use \emph{Cites} and
494 msdemlei 3958 in particular declare relationships to tools. If these are not
495     registred, use the name of their binary name as the name of the related
496     resource; this will very typically be lowercase-only.
497 volute@g-vo.org 2412
498 msdemlei 3960 Each \vorent{Edition}-typed capability should
499     correspond to a translation of the document. It
500 msdemlei 3958 is recommended to list the English-language version first if it exists.
501 volute@g-vo.org 2412
502 msdemlei 3960 The following description of the \vorent{doc:Edition} capability
503     is generated from the schema file.
504 msdemlei 3958
505 msdemlei 3960 % GENERATED: !schemadoc DocRegExt-1.xsd Edition
506     \begin{generated}
507     \begingroup
508     \renewcommand*\descriptionlabel[1]{%
509     \hbox to 5.5em{\emph{#1}\hfil}}\vspace{2ex}\noindent\textbf{\xmlel{doc:Edition} Type Schema Documentation}
510    
511     \noindent{\small
512 msdemlei 4010 An “edition” (typically: translation) of the document.
513 msdemlei 3960 \par}
514    
515     \noindent{\small
516     Although for a while, multiple editions of the document in one language
517 msdemlei 4010 may be given (corresponding perhaps to two “major” versions), in
518 msdemlei 3960 general, only the latest version of the document per language should be
519     given.
520    
521     At least one vr:WebBrowser-typed interface with
522     role="rendered" must be present. The access URL of the interface
523     points to a rendered version of the edition (preferably in PDF,
524     but HTML is acceptable, too).
525    
526     Editors are strongly encourated to also provide an
527     interface with role="source", the accessURL of which should point
528     to an editable version of the document, a version controlled
529     repository, or the like.
530     \par}
531    
532     \vspace{1ex}\noindent\textbf{\xmlel{doc:Edition} Type Schema Definition}
533    
534     \begin{lstlisting}[language=XML,basicstyle=\footnotesize]
535     <xs:complexType name="Edition" >
536     <xs:complexContent >
537     <xs:extension base="vr:Capability" >
538     <xs:sequence >
539     <xs:element name="language" type="xs:token" minOccurs="1"
540     maxOccurs="1" />
541     <xs:element name="locTitle" type="xs:token" minOccurs="0"
542     maxOccurs="1" />
543     </xs:sequence>
544     </xs:extension>
545     </xs:complexContent>
546     </xs:complexType>
547     \end{lstlisting}
548    
549     \vspace{0.5ex}\noindent\textbf{\xmlel{doc:Edition} Extension Metadata Elements}
550    
551     \begingroup\small\begin{bigdescription}\item[Element \xmlel{language}]
552     \begin{description}
553     \item[Type] string: \xmlel{xs:token}
554     \item[Meaning]
555     The language this document is (mainly) written in,
556     as an RFC 3066 language code.
557    
558     \item[Occurrence] required
559     \item[Comment]
560     The country codes must be given in all lowercase. This
561     results in strings like en-us, de-de, or es-mx.
562    
563     This language is also the language for locTitle,
564     irrespective or that element's xml:lang setting.
565    
566    
567     \end{description}
568     \item[Element \xmlel{locTitle}]
569     \begin{description}
570     \item[Type] string: \xmlel{xs:token}
571     \item[Meaning]
572     \item[Occurrence] optional
573    
574     \end{description}
575    
576    
577     \end{bigdescription}\endgroup
578    
579     \endgroup
580     \end{generated}
581    
582 msdemlei 3958 % /GENERATED
583    
584     \subsection{DocRegExt in RegTAP}
585     \label{sect:docregext-regtap}
586    
587 msdemlei 3956 In the relational registry \citep{2014ivoa.spec.1208D}, DocRegExt is
588 msdemlei 3960 straightforwardly represented in the standard VOResource tables. in
589     particular, to find all titles and access urls for documents, one would
590     write:
591 volute@g-vo.org 2412
592 msdemlei 3960 \begin{lstlisting}[language=SQL]
593     SELECT res_title, access_url FROM
594     rr.resource
595     NATURAL JOIN rr.interface
596     WHERE
597     res_type='doc:document'
598     and intf_role='rendered'
599     \end{lstlisting}
600 volute@g-vo.org 2412
601 msdemlei 3960 The \vorent{language} and \vorent{locTitle} elements from the
602     \vorent{doc:Edition} capability extension are mapped into
603     \verb|res_details| with the following \verb|detail_xpath|s:
604    
605 msdemlei 3956 \begin{itemize}
606 volute@g-vo.org 2412
607 msdemlei 3958 \item \texttt{/capability/language} -- the document language as an RFC
608     3066 language code.
609 msdemlei 3960 \item \texttt{/capability/locTitle} -- the title in the national
610     languate.
611     \end{itemize}
612 msdemlei 3956
613 msdemlei 3960 The downside of not defining an extra table for the documents is that
614     the query patterns in RegTAP are somewhat clumsy. For instance, to list
615     the English and Italian titles of all texts available in Italian, one
616     has to carefully join two subqueries to \verb|res_details|:
617 msdemlei 3956
618 msdemlei 3960 \begin{lstlisting}[language=SQL]
619     SELECT res_title, loctitle FROM
620     rr.resource
621     NATURAL JOIN (
622     SELECT ivoid, loctitle FROM (
623     SELECT ivoid, cap_index, detail_value as loctitle
624     FROM rr.res_detail
625     WHERE detail_xpath='/capability/locTitle') AS titles
626     NATURAL JOIN (
627     SELECT ivoid, cap_index
628     FROM rr.res_detail
629     WHERE
630     detail_xpath='/capability/language'
631     AND detail_value LIKE 'it_%') AS italiancaps
632     ) as loctitles
633     WHERE
634     res_type='doc:document'
635     \end{lstlisting}
636 msdemlei 3956
637    
638 msdemlei 4010 Here is a (slightly abridged) example record\todo{Update this to the new
639     schema}:
640 msdemlei 3960
641 msdemlei 3958 \lstinputlisting[language=XML,basicstyle=\footnotesize]{m1distance-example.xml}
642 marco.merot@gmail.com 2415
643 msdemlei 3956 \subsection{A versioned repository for tutorials}
644    
645     \label{sect:svn-repo}
646    
647 msdemlei 3957 Registering text document as VO resources allows searching for tutorials
648     and similar
649     material through standard registry interfaces, but keeping
650 marco.merot@gmail.com 2425 tutorials up to date, in their master form and also in their translated
651 msdemlei 4010 versions, is an obviously important management issue not really
652     addressed by the Registry.
653    
654     For tracking changes and versions, the standard tool is a version
655     control system. Therefore,
656     a versioned repository (using subversion as the version control system)
657 msdemlei 3956 has been set up at GAVO data
658 msdemlei 4010 center\footnote{\url{http://svn.ari.uni-heidelberg.de/svn/edu/}}.
659     It collects part of the
660     already existing VO tutorials with the goal of preserving them and
661     letting users
662 msdemlei 3957 update and translate them.
663 msdemlei 3956
664 msdemlei 4010 The repository has an internal structure designed to enable:
665    
666 msdemlei 3956 \begin{itemize}
667    
668     \item different national languages (master language set to english){}
669    
670     \item translation vs. master language updates{}
671    
672     \item licensing, in order to clarify how and whether a tutorial can be changed or re-used{}
673    
674     \item additional materials used by tutorials{}
675    
676     \item access roles to allow everyone to access tutorials but prevent untrusted updates or additions to it{}
677    
678     \end{itemize}
679    
680 msdemlei 3957 Details of this structure are discussed in a \texttt{README} file at the
681     root of the
682     repository\footnote{\url{http://svn.ari.uni-heidelberg.de/svn/edu/README}}.
683 marco.merot@gmail.com 2429 The repository is intended to work as a space for cooperative
684     VO tutorials development.
685 volute@g-vo.org 2412
686 marco.merot@gmail.com 2425
687 volute@g-vo.org 2304
688 msdemlei 3956
689     \appendix
690    
691     \section{ContentLevel values summary}
692    
693     \label{app:clcurrval}
694    
695    
696 marco.merot@gmail.com 2311 This appendix reports some statistics on the usage of the ContentLevel
697 msdemlei 3956 element in \citep{2008ivoa.spec.0222P} as of 2014-01-30, taken from the
698 marco.merot@gmail.com 2408 GAVO RegTAP endpoint http://dc.g-vo.org/tap .
699     There are 14392 useful resources (excluding authorities, standards and
700     similar) that expose 26 different values as their ContentLevel.
701 msdemlei 3956 In table \ref{tab:cldist} these values are reported in order of count.
702    
703    
704    
705     \begin{table}
706     \begin{tabular}{lp{12cm}}
707     \sptablerule
708     \textbf{count}&
709     \textbf{content\_level string}\\
710     \sptablerule
711     13937&research\\
712     290&\\
713     41&university research\\
714     40&general university research amateur\\
715     24&university\\
716     14&university research amateur\\
717     7&general\\
718     5&research general\\
719     4&general research\\
720     3&secondary education community college university research amateur\\
721     3&research university community college\\
722     3&elementary education middle school education secondary education\\
723     3&general university research\\
724     2&research university\\
725     2&research amateur university community college\\
726     2&general informal education\\
727     2&general elementary education middle school education secondary education community college university research amateur informal education\\
728     1&university community college research\\
729     1&general university research amateur informal education\\
730     1&elementary education middle school education secondary education community college university research\\
731     1&general secondary education university research\\
732     1&university research general informal education\\
733     1&research university amateur\\
734     1&elementary education middle school education secondary education community college university research amateur\\
735     1&elementary education middle school education secondary education community college university research amateur informal education\\
736     1&university research amateur informal education\\
737     1&general university research informal education\\
738     \end{tabular}
739     \caption{Empirical distribution of \vorent{ContentLevel}s declared by VO
740     resources.}
741     \label{tab:cldist}
742     \end{table}
743    
744    
745    
746 marco.merot@gmail.com 2311 This table can be easily updated from the same endpoint (or an analogue
747     one) using the following ADQL query:
748 msdemlei 3956
749     \begin{verbatim}
750 marco.merot@gmail.com 2311 SELECT
751     count(*) as cnt, content_level
752     FROM
753     rr.resource
754     WHERE
755 msdemlei 3957 res_type not in ('vstd:servicestandard', 'vg:authority',
756     'vstd:standard', 'va:application', 'vr:organization')
757 marco.merot@gmail.com 2311 GROUP BY content_level
758     ORDER BY cnt DESC
759 msdemlei 3956 \end{verbatim}
760 volute@g-vo.org 2412
761 msdemlei 3956 The table shows that only about 1\% of the ContentLevel values use
762     something different and more complex than
763     \emph{research}, when
764     the element is not empty. Morever, of this 1\% (165 resources),
765     61 include the \emph{general} value (roughly 37\% of them),
766     29 (17\%) state that are devoted to some
767     \emph{education} level only,
768     while 148 (90\%) state that are also devoted to some
769     \emph{education} level (up to
770     \emph{university}).
771 volute@g-vo.org 2412
772 msdemlei 3956 \bibliography{ivoatex/ivoabib,ivoatex/docrepo}
773    
774     \end{document}

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