<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">I don't think that these are OAI-PMH data transport issues, but application issues that arise from the interpretation and usage of metadata from heterogenous data providers.<div><br class="webkit-block-placeholder"></div><div>Managing duplicates: while it makes life inconvenient for your service users, it is not something that can in general be controlled by independent data providers. I'm afraid that your service must have the ability to reconcile duplicate (or near duplicate) items.</div><div><br></div><div>Controlled vocabularies for types: you will need to make a recommendation and try to gain support among the OAI data providers. I am not sure that the selection that you propose will work in practice. Is a PDF a text if it has embedded images? Is an image a text if it is an OCR scan?</div><div><br class="webkit-block-placeholder"></div><div>Enforced publication dates: what do you enforce if the item has never been officially published?</div><div>--</div><div>Les Carr</div><div><br class="webkit-block-placeholder"></div><div><br class="webkit-block-placeholder"></div><div><div></div><div><div><div>On 5 Dec 2007, at 09:40, Frederic MERCEUR wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"> <div bgcolor="#ffffff" text="#000000"> <small><font face="Helvetica, Arial, sans-serif">Hello, <br> <br> Further to the previous email I sent about the <a href="http://www.ifremer.fr/docelec/doc/2007/acte-3238.pdf">document</a> we redacted to assess the main difficulties met during the first year of management of our <a href="http://www.ifremer.fr/avano/">Avano</a> harvester, I would like to focus, in this email, on just 3 problems linked to the OAI-PMH protocol, Dublin Core or to repositories implementation. I would like to focus particularly on these 3 problems because I guess they should not be so difficult to fix. <br> <br> <br> <big><b>Managing duplicates </b></big><br> <br> Too many duplicates in a result list in Harvesters list can affect the user’s comfort. This is not the main problem harvesters are facing today, but this should increase in the coming years. Today, at least two phenomenons can generate duplicates in the harvesters’ databases: <br> </font></small> <ul> <li><small><font face="Helvetica, Arial, sans-serif">Several research organisations or universities can record the same electronic resource in their own institutional repository. If Avano harvests those repositories, it will get descriptive index files of the same topic stored in several places. This can happen if, for example, a publication is written in collaboration with several institutions. If so, this publication may be archived on the server of each institution. Considering the current low auto-archiving rate, especially in life sciences, this phenomenon is not the main cause of the production of duplicates.</font></small></li> <li><small><font face="Helvetica, Arial, sans-serif">Projects for national or thematic aggregators can pose problem. In some countries, projects of merged institutional repositories can agregate records from a selection of repositories in a centralised database before displaying them again in OAI-PMH on their own server. As a consequence, records referenced on those servers are displayed twice in OAI-PMH: via the institutional repository and via the centralised database. If the manager of an harvester does not know about the architecture of those national or thematic projects, he may record the two different servers and generate duplicates in his harvester’s result lists. </font></small></li> </ul> <small><font face="Helvetica, Arial, sans-serif"><i>To help harvesters administrator to avoid recording repositories generating duplicates, could we imagine adding to the description of the repository information about the involvement of the said repository in a national or thematic agregation system that would reexpose the records in OAI-PMH from a different server? <br> </i><br> <br> <big><b>Managing Type and Date field</b></big><br> <br> As far as I understand, in order to comply with the OAI-PMH protocol, repositories have to expose their data in the non-qualified Dublin Core DTD. In this DTD all fields are optional. Those fields are also non-qualified, meaning, for example, that they do not have to correspond to an enclosed value list. This optional and non-formalised information trait raises several issues, especially for the Type field. <br> <br> Indeed, even if the Dublin Core DTD recommends storing the Type information by using standardised text strings, few repositories take this into consideration and still present the information as free text (ex: publication, artjournal, text, article are used to describe an article). Some harvesters, including Avano, offer their users to limit their search to one or several types of resources. To set up this filter, harvesters try to standardise the Type field using a system based on key-word recognition in this character string. This standardising is therefore imperfect and the filter system may exclude resources from the result list when a user narrows his search to one or several types of specific data. Some informations contained in this Type field cannot be standardised.<br> <br> Even more problematic is the fact that some repositories do not fill in this field. As an example, in September 2007, out of the 107.000 records available in Avano, more than 26.000 did not have a Type field. All of those records are automatically barred from the search space if a user limits is search to one or several selected types. <br> <br> <i>Could it be possible to imagine getting a new normalised and mandatory information about the type of the digital object (text, image, video….) so harvesters could offer an reliable option to filter one or several types ob objects from the end-user search.<br> </i><br> The publication date is also problematic for harvester. For example, In September 2007, out of the 107.000 records available in Avano, about 15.000 did not have a publication date. When a record does not have a publication date or when it cannot be standardised, it is automatically located at the end of the list if the user wants the results to be sorted by date. In the same way, when a user limits his search to a specific period of time (see fig. 9), those files are barred from the search even if they correspond to the specified search. <br> <br> But I guess this problem with the publication date will be more difficult to fix because it is difficult to define it as mandatory. <br> <br> <br> <b><big>Records without free access to the digital object</big></b><br> <br> As far as I understand, the OAI-PMH protocol defines only the sharing process of bibliographical records contained in a group of repositories. As a consequence, some repositories mix records without links to the digital object together with records providing free access to the resource. Others provide records with paying access (ex : BePress) or records with restricted access, for example, for university staff. <br> <br> In my opinion, this is the major problem harvesters have to face today. There is no indication in the Dublin Core DTD showing the harvesters the degree of accessibility of the objects described in the records. As a consequence, harvesters cannot pass on this information to their users or provide them with the ability to filter empty records or records offering paying access to the resource. <br> <br> It is my opinion that hiding records with free full text among records with inaccessible full text is not helpful. For lack of time and/or interest, scientists are reluctant to join the Open Access movement and the archiving rate of free access publications stays very low, especially in life sciences. Free and immediate access to documentation is, without doubt, the best way to convince the scientists of the interest of the Open Access movement. And drowning a minority of records providing free access publications in an ocean of records without link to the full text and/or records offering paying access to the documents may not be the best way to promote the Open Access movement. <br> <br> Again, those records without free access to the full text would not be a problem for the harvesters if the Dublin Core DTD enabled to signify the harvesters the degree of accessibility of the objects described in the records. Harvesters could then provide their users with the possibility of filtering the records without free access to the digital object. But it is still not the case. <br> <br> <i>Could we then imagine that, in a possible future version of the OAI-PMH, each record will have to provide a normalised and mandatory information about the degree of accessibility of the digital object (free, paying, impossible, restricted,...)? This will help harvesters so much to provide a better service to theirs end-users. <br> </i><br> <br> What do you think?<br> <br> Kind regards,<br> Fred<br> </font></small><br> <div class="moz-signature">-- <br> <font face="Arial" size="2">Fred Merceur<br> Ifremer / Bibliothèque La Pérouse<br> <a class="moz-txt-link-abbreviated" href="mailto:frederic.merceur@ifremer.fr">frederic.merceur@ifremer.fr</a><br> Tél : 02-98-49-88-69<br> Fax : 02-98-49-88-84<br> <a href="http://www.ifremer.fr/blp/">Bibliothèque La Pérouse</a><br> <a href="http://www.ifremer.fr/docelec/">Archimer, Ifremer's Institutional Repository</a><br> <a href="http://www.ifremer.fr/avano/">Avano, a marine and aquatic OAI harvester</a><br> </font></div> </div> _______________________________________________<br>OAI-implementers mailing list<br>List information, archives, preferences and to unsubscribe:<br><a href="http://www.openarchives.org/mailman/listinfo/oai-implementers">http://www.openarchives.org/mailman/listinfo/oai-implementers</a><br><br></blockquote></div><br></div></div></body></html>