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=Nepomuk=
=Semantic Search=


El objetivo de esta página no es explicar de forma exhaustiva la tecnología de Nepomuk y cada detalle, sino dar una visión general, algunos ejemplos, compartir lo que hay detrás de él y enlazar a información relevante en la web.
The aim of this page is not to fully explain KDE's Semantic Search technology and every detail, but to give a short overview, some examples, share the vision behind it and link to relevant information on the web.
 
== Baloo is the next generation of semantic search ==
 
From KDE Applications 4.13 onwards, the '[https://community.kde.org/Baloo Baloo]' file indexing and file search framework replaces Nepomuk. Read [http://dot.kde.org/2014/02/24/kdes-next-generation-semantic-search details on the changes for Applications 4.13 here]. Semantic Search no longer uses a single, big database, but separate, specialized databases for each type of data. The new search databases are in <tt>$HOME/.local/share/baloo</tt>. If you upgraded to KDE Applications 4.13 from an earlier KDE release, you can delete <tt>$KDEHOME/share/apps/nepomuk</tt>.


==Breve explicación==
==Breve explicación==


Como menciona el [[Special:myLanguage/Glossary#Nepomuk|Glosario]], Nepomuk trata la clasificación, organización y presentación de datos. No es una aplicación sino un componente que puede ser utilizado por los desarrolladores dentro de sus aplicaciones
As the [[Special:myLanguage/Glossary#Nepomuk|Glossary]] mentions, Semantic Search is about classification, organisation and presentation of data. It is not an application, but a component which can be used by developers within applications.


<span class="mw-translate-fuzzy">
=== Try out in Dolphin ===
=== Pruébalo ===
For example, the [[Special:myLanguage/Dolphin|Dolphin]] file manager makes use of Search. In KDE Applications versions prior to 4.13 Semantic Search must be enabled from <menuchoice>System settings -> Desktop search</menuchoice>. The information sidebar of Dolphin (<menuchoice>Control -> Panels -> Information</menuchoice>, or press <keycap>F11</keycap>) presents information extracted by Search about the selected file, and also allows you to assign tags, ratings and comments to files. This information is then stored and indexed by Search. You can then search for metadata using the navigation bar in Dolphin. Click to <menuchoice>Find</menuchoice>, or press <keycap>Ctrl+F</keycap>, and search for file names or file contents.
Por ejemplo, [[Special:myLanguage/Dolphin|Dolphin]] hace uso de Nepomuk. Para lo siguiente Nepomuk y Strigi deben estar activados en <menuchoice>System settings -> Búsqueda de Escritorio</menuchoice>. La barra lateral de información de Dolphin te permite asignar etiquetas, valoraciones y comentarios a los archivos. Esta información es almacenada en Nepomuk e indexada por Strigi. Puedes buscar por metadatos utilizando la barra de navegación de Dolphin. Escribe "nepomuksearch:/" seguido de los términos de búsqueda.
</span>


<!-- info about nepomuksearch:/ deleted per its developer: "Actually nepomuksearch:/ is an internal thing and should not be entered by the user." its developer -->
<!-- info about nepomuksearch:/ deleted per its developer: "Actually nepomuksearch:/ is an internal thing and should not be entered by the user." its developer -->
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==Funcionalidades==
==Funcionalidades==


Nepomuk ofrece varias 'capas' de funcionalidad para las aplicaciones. La primera y más simple de ellas es el etiquetado manual, valoraciones y comentarios, como se usan en Dolphin. Esto te ayudará a encontrar tus archivos más rápido, pero también supone mucho trabajo.
KDE's Semantic Search offers several 'layers' of functionality to applications. The first and most simple of those is manual tagging, rating and commenting, as used in Dolphin. This helps you to find your files faster, but is also a lot of work.


<span class="mw-translate-fuzzy">
To make finding files containing text easier, Search offers a second functionality: indexing the text of files. You can find files by entering some words which you know are in there, or just (part of) their title.
Para facilitar la búsqueda de archivos que contengan cierto texto, Nepomuk ofrece una segunda funcionalidad: indexación del texto de los archivos. Utiliza una tecnología llamada [[Special:myLanguage/Glossary#Strigi|Strigi]] para ésto. Puedes buscar archivos introduciendo algunas palabras que sepas que están ahí o,  simplemente, parte de su título.
</span>


La tercera capa es muy compleja, y es la razón de que Nepomuk fuera concebido como un proyecto de investigación de varias compañías y universidades de la Unión Europea. Aquí encontrarás palabras difíciles como 'escritorio semántico' y 'ontologías'. Básicamente, se trata de contextos y relaciones.
The third layer is a very complex one, and the reason why the underlying technology, Nepomuk, was conceived as a research project of several companies and universities in the European union. This is where you will find difficult words like 'semantic desktop' and 'ontologies'. Basically, it is about context and relationships.


=== Indexing files ===
=== Indexing files ===


Strigi does not index every file on the hard drive. Its default configuration in most Linux distributions excludes some common patterns for backup files and configuration directories, and it only indexes certain directories in your home folder. You can change this in <menuchoice>System Settings -> Desktop Search -> Desktop Query -> Customize index folders… -> Folders to index</menuchoice>.
Search does not index every file on the hard drive. Its default configuration in most Linux distributions excludes some common patterns for backup files and configuration directories. You can change this in <menuchoice>System Settings -> Desktop Search</menuchoice>. Add folders to be excluded. If you want to turn off indexing of files entirely, just add your home folder there.
 
Note that Strigi as of KDE 4.7 does not follow symbolic links ({{bug|208602}}). Up to KDE 4.9, even if the user selects folders under the symbolic link for indexing ({{bug|287593}}), content will not been indexed. The specific bug has been fixed. Thus, the user will be able to see the symbolic links, but she/he will not be allowed to mark any of them for indexing. (A symbolic link is a file that "points" to another file or directory; Dolphin displays symbolic links in ''italic''.) You must find the path to the actual directory (in '''Dolphin''', select the file, choose <menuchoice>Properties -> General -> Points to</menuchoice>) and tell Strigi to index that.


In '''System Settings''' you can also control whether Strigi indexes files on removable media such as USB drives and CD-ROMs.
In '''System Settings''' you can also control whether Search indexes files on removable media such as USB drives and CD-ROMs. In KDE Applications 4.13 this is not available, removable media are not indexed. Future versions are planned to reintroduce this functionality.


==Ejemplos==
==Ejemplos==


Déjame que te explique lo que ofrece Nepomuk con dos ejemplos.
Let me try to explain what Semantic Search offers using two examples. These features are not available fully yet - the base is there but application developers need to integrate this in their applications.


===Relaciones===
===Relaciones===
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Digamos que has recibido una foto de un amigo tuyo, hace dos semanas, y la guardaste en algún lugar en tu ordenador. ¿Cómo encuentras ese archivo ahora? A menos que sepas la ubicación, no tiene buena pinta.
Digamos que has recibido una foto de un amigo tuyo, hace dos semanas, y la guardaste en algún lugar en tu ordenador. ¿Cómo encuentras ese archivo ahora? A menos que sepas la ubicación, no tiene buena pinta.


Nepomuk tiene como objetivo ayudarte. Tú sabes que este archivo vino de ese amigo tuyo, pero tu equipo no. Nepomuk, sin embargo, puede recordar esta relación, ¡de forma que al buscar el nombre de tu amigo aparezca la foto!
Now Semantic Search aims to help you. You know this file came from that friend of yours, your computer does not know. Search, however, can remember this relationship. Searching on the name of your friend will therefore pop up the photo!


Otra posible relación es entre una página web de la que has copiado texto y el documento en el que lo has pegado, o dos imágenes mostrando el mismo coche. Estas relaciones a veces pueden ser extraídas de los propios archivos (puedes analizar fotografías y ver quien o qué aparece en ella) o proporcionadas por las aplicaciones involucradas (como en el ejemplo sobre correo electrónico anterior). Esta parte de Nepomuk está todavía bajo un fuerte desarrollo, y necesita integración con las aplicaciones, por lo que puede tardar unos cuantos años hasta que de verdad brille.
Another potential relationship is between a web page you copied text from and the document you pasted it into, or two images showing the same car. Such relations can sometimes be extracted from the files themselves (you could analyze photos and see who or what is on there) or supplied by the applications involved (as in the above email example). This part of Search is still under heavy development, and needs integration in applications, so you can expect it to take a few more years to really shine.


En conjunto, esta parte de Nepomuk trata de hacer búsquedas inteligentes. Piensa acerca de cómo Google intenta ser inteligente con tus búsquedas: cuando buscas por un hotel y el nombre de una ciudad, muestra sobre los resultados un mapa que muestra hoteles en la ciudad mencionada. Incluso puede sugerirte un mejor nombre en caso de que hayas cometido un error ortográfico. Google también trata de poner la información mas relevante al principio de la lista de resultados, utilizando complejos cálculos sobre relaciones (enlaces) entre páginas web. Nepomuk será capaz de ofrecer este tipo de resultados inteligentes y ordenarlos según relevancia utilizando la información sobre relaciones.
All in all, this part of Semantic Search is about making search smart. Think about how Google tries to be smart with your searches: when you search for a hotel and a city name, it shows above the website results a google map showing hotels in the city you mentioned! It might even suggest a better name in case you made a spelling mistake. Google also tries to put the most relevant information on top of the list of results, using complex calculations on relationships (links) between websites. Semantic Search will be able to offer such smart results and order them on relevancy using relationship information.


===Contexto===
===Contexto===


Estas relaciones no solo pueden ayudarte a buscar archivos, sino que también tienen influencia en las aplicaciones y en la información que presentan. ¡Ten en cuenta que esta forma de usar Nepomuk es más una visión que una realidad! Muchos de los componentes están en su sitio, pero no han sido integrados en las aplicaciones ni en el escritorio en su conjunto.
These relationships can not only help you while searching for files, but also have an influence on applications and what information they present. Note that this way of using Search is still more a vision than reality! Many of the components are in place, but it is not yet integrated in applications and the desktop as a whole.


Aquí tienes un ejemplo de como llevar la información contextual a tu escritorio puede ayudarte a trabajar de forma más eficiente.
Aquí tienes un ejemplo de como llevar la información contextual a tu escritorio puede ayudarte a trabajar de forma más eficiente.
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Sería bueno poder organizar todo un poco mejor ¿verdad?
Sería bueno poder organizar todo un poco mejor ¿verdad?


Aparecen las '[[Special:myLanguage/Glossary#Actividades|actividades]]'. Estas han sido introducidas en [[Special:myLanguage/Plasma|Plasma]], y actualmente ofrecen distintos 'escritorios'. Son similares a los escritorios virtuales, pero donde lo que cambia es el escritorio en si, no las aplicaciones. Diferentes elementos gráficos, fondo de pantalla y cosas así. Por supuesto, desde KDE 4.3, cada escritorio virtual puede tener su propia actividad, con los dos en sincronía.
Enter '[[Special:myLanguage/Glossary#Activities|activities]]'. These have been introduced in [[Special:myLanguage/Plasma|Plasma]], and currently offer different 'desktops'. They are a bit like virtual desktops, except that the desktop itself changes, not the set of applications. Different widgets, background, things like that. Of course, since Plasma 4.3, each virtual desktop can have its own activity, bringing the two in sync.


Si las aplicaciones y el escritorio estuvieran al tanto de las actividades, podrías crear una actividad para cada una de las tareas en las que trabajes regularmente. Por tanto, si normalmente cambias a una hoja de cálculo con precios, puedes crear una actividad para eso: pon un elemento de Vista de Carpeta (o varios) en el escritorio, añade una calculadora y un elemento de tareas pendientes para seguir la pista de lo que aún debes cambiar. ¡Quizás incluso un elemento de carpetas de correo electrónico mostrando los correos con preguntas relacionadas con esa hoja de cálculo!
Si las aplicaciones y el escritorio estuvieran al tanto de las actividades, podrías crear una actividad para cada una de las tareas en las que trabajes regularmente. Por tanto, si normalmente cambias a una hoja de cálculo con precios, puedes crear una actividad para eso: pon un elemento de Vista de Carpeta (o varios) en el escritorio, añade una calculadora y un elemento de tareas pendientes para seguir la pista de lo que aún debes cambiar. ¡Quizás incluso un elemento de carpetas de correo electrónico mostrando los correos con preguntas relacionadas con esa hoja de cálculo!
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Por supuesto, lo anterior es sobre todo relevante para la gente que trabaja con su ordenador en una oficina o en casa. Un jugador o un usuario casual probablemente no utilizarán estas actividades.
Por supuesto, lo anterior es sobre todo relevante para la gente que trabaja con su ordenador en una oficina o en casa. Un jugador o un usuario casual probablemente no utilizarán estas actividades.


Ten en cuenta que el escenario descrito arriba está todavía a años luz de la realidad. Gran parte de la infraestructura para esto en KDE está en su sitio pero todavía hay mucho que hacer.
The scenario described above is already partially implemented in the Activities but much work is still left.


==Frequently Asked Questions==
==Frequently Asked Questions==
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;What is the Nepomuk Semantic Desktop, and the Strigi Desktop File Indexer?
;What is the Nepomuk Semantic Desktop, and the Strigi Desktop File Indexer?


:The Nepomuk Semantic Desktop is the foundation of the all the other modules of the Nepomuk infrastructure. It provides a way to organize, annotate and build relationships among the data (not only file name and content, but for example which applications used a certain file, or how it is tagged). A number of KDE applications and workspaces use this basic infrastructure to deliver features such as email tagging ([[Special:myLanguage/KMail|KMail]]) or activity setup (Plasma).  
: Nepomuk and Strigi are technologies part of what delivers the abilities of the Semantic Search in KDE. Both are not used directly in the latest generation of KDE's Semantic Search ([http://dot.kde.org/2014/02/24/kdes-next-generation-semantic-search details]), however their successors share much of their code and concepts. Semantic Search provides a way to organize, annotate and build relationships among the data (not only file name and content, but for example which applications used a certain file, or how it is tagged). A number of KDE applications and workspaces use this basic infrastructure to deliver features such as email tagging ([[Special:myLanguage/KMail|KMail]]) or activity setup (Plasma).  


:On the other hand, the Strigi Desktop File Indexer is a system to index files so that they can be added to the main Nepomuk repository, a convenient way to use them within Nepomuk without adding any file manually. Also, applications such as [[Special:myLanguage/Dolphin|Dolphin]] can then search for files basing on content, name, or other meta-data (e.g. tags) associated to indexed files. Such an indexer can also index non-text files, such as PDFs, by accessing the meta-data contained in these files (author, publication information, etc.). Some KDE components ship additional "analyzers" for more file types. Nepomuk can be fully functional without the use of the File Indexer, which is an additional (and optional) component.
:The file indexing allows applications such as [[Special:myLanguage/Dolphin|Dolphin]] to search for files based on content, name, or other meta-data (e.g. tags) associated to indexed files. Such an indexer can also index non-text files, such as PDFs, by accessing the meta-data contained in these files (author, publication information, etc.). Some KDE components ship additional "analyzers" for more file types.


; Why do we need both Akonadi and Nepomuk?  Aren't they doing the same thing?
; Why do we need both Akonadi and Semantic Search?  Aren't they doing the same thing?


:There is often a good deal of confusion about Akonadi and Nepomuk. [http://cmollekopf.wordpress.com/2013/02/13/kontact-nepomuk-integration-why-data-from-akonadi-is-indexed-in-nepomuk/ Why data from Akonadi is indexed in Nepomuk] explains exactly why we have both, and what their roles are.  Don't miss the additional information from [http://en.opensuse.org/User:Wstephenson Will Stephenson] in the Comments section.
: In short, Akonadi provides a cache of PIM data like calendar items, contacts and email, which is used by applications like KMail and Korganizer but also the calendar build in Plasma. Semantic Search plugs in Akonadi to provide search functionality. How Baloo offers search is actually up to the application. In case of KDE PIM, Xapian is used to provide indexing and search.


;How can I disable the semantic desktop?
;How can I disable the semantic desktop?


:Most of the times, the easiest way is to disable file indexing, which is usually, among the Nepomuk components, the heavier in resource usage (although many optimizations were included in the 4.7 release which has reduced resource usage). This is done by unchecking <menuchoice>Enable Nepomuk File Indexer</menuchoice> in the [[Special:myLanguage/System_Settings/Search_Desktop|Desktop Search]] section of [[Special:myLanguage/System Settings|System Settings]]. In case you want to turn off all semantic features, uncheck <menuchoice>Enable Nepomuk Semantic Desktop</menuchoice>. Notice that this will turn off search in [[Special:myLanguage/Dolphin|Dolphin]] as well.
: File indexing can be disabled by adding the users' home folder to the <menuchoice>System Settings -> Desktop Search -> Do not search in these locations list</menuchoice>. The other functionality is part of the applications that use it and thus can't be disabled without crippling these applications. For example, to not have any search in KMail you'll have to simply remove KMail...
 
In versions of the KDE Applications before 4.13, Semantic Search would have components running separate from applications. This functionality could be disabled by unchecking <menuchoice>Enable Nepomuk File Indexer</menuchoice> in the [[Special:myLanguage/System_Settings/Search_Desktop|Desktop Search]] section of [[Special:myLanguage/System Settings|System Settings]]. In case you want to turn off all semantic features, uncheck <menuchoice>Enable Nepomuk Semantic Desktop</menuchoice>. Notice that this will turn off search in [[Special:myLanguage/Dolphin|Dolphin]] as well.
 
:Notice that with the latter option some programs who use Semantic Search for meta-data will offer reduced functionality: for example [[Special:myLanguage/KMail|KMail]] will not be able to tag mail, or Plasma activities will not offer additional features such as icons, or program data information.
 
;Baloo/Semantic Search is eating 100% CPU! What do I do?


:Notice that with the latter option some programs who use Nepomuk for meta-data will offer reduced functionality: for example [[Special:myLanguage/KMail|KMail]] will not be able to tag mail, or Plasma activities will not offer additional features such as icons, or program data information.  
:Just wait. Certain files are very hard or even impossible to Index. At the moment, this includes for example text files of over 50 megabyte. When Search finds these, it will try for a fixed time. When it fails, it will try to find out what file is broken and disable indexing it in the future. As it indexes files in batches of about 40, it has to find the problematic file by indexing that bunch in parts: first half/second half, index problematic half in pieces again, until the file is found. This can take up to 30 minutes of heavy cpu usage. Unfortunately, while Baloo will not start to index a new batch of 40 files while on battery power, it continues to determine the broken file while on battery. This behaviour has been fixed in in KDE Applications 4.13.1 (it will stop indexing immediately when the power cord is unplugged) and the time the search for each file can take has been reduced to about 10 minutes. The Semantic Search team is working on improving the indexing tools to handle more difficult files.


;Why do I have nepomukservicestub processes even though I've disabled Nepomuk?
;Why do I have nepomukservicestub processes even though I've disabled Nepomuk?
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:It may be a bug. Please file a [http://bugs.kde.org bug report] with a complete description of your problem and the steps to trigger it.
:It may be a bug. Please file a [http://bugs.kde.org bug report] with a complete description of your problem and the steps to trigger it.


:File indexing of PDF/some other file types doesn't work.
;File indexing of PDF/some other file types doesn't work.


:PDF indexing is a known issue and it's being tracked in {{bug|231936}}. If you have issues with other files, open a bug, preferably adding a sample file that shows the problem.
:PDF indexing is a known issue and it's being tracked in {{bug|231936}}. If you have issues with other files, open a bug, preferably adding a sample file that shows the problem.


:The program nepomukservicestub crashes at startup.
;The program nepomukservicestub crashes at startup.


:A large number of fixes for crashes has been fixed for the 4.7.2 release of the KDE Workspaces and Applications. If you encounter more, please file bugs report with detailed instructions on how to reproduce the problem, as sometimes the developers are unable to trigger them in their test setups.
:A large number of fixes for crashes has been fixed for the 4.7.2 release of the KDE Workspaces and Applications. If you encounter more, please file bugs report with detailed instructions on how to reproduce the problem, as sometimes the developers are unable to trigger them in their test setups.


:The virtuoso-t process hangs at 100% CPU.
;The virtuoso-t process hangs at 100% CPU.
 
:Virtuoso-t is a key component of the old Semantic Search infrastructure and in some occasions the commands sent by the other components end up taking too much time (hence showing the effect of 100% CPU).


:Virtuoso-t is a key component of the Nepomuk infrastructure and in some occasions the commands sent by the other components end up taking too much time (hence showing the effect of 100% CPU). Sebastian Trüg (the lead developer of Nepomuk) has fixed most of these problems in 4.7.1 or newer.
Virtuoso is no longer used by Semantic Search starting the Applications 4.13 release.


:Sometimes Nepomuk consumes too much RAM.
;Sometimes Nepomuk consumes too much RAM.


:Many of these problems have been fixed, in other cases however the developers are unable to reproduce the issues correctly. In this case, providing examples and test cases to [http://bugs.kde.org/ bug reports] increase the chances to get these bugs fixed.
:Many of these problems have been fixed, in other cases however the developers are unable to reproduce the issues correctly. In this case, providing examples and test cases to [http://bugs.kde.org/ bug reports] increase the chances to get these bugs fixed.


:Nepomuk re-indexes files at startup.
;Search accesses the disk too much on startup.:
 
:This bug has been fixed in 4.7.0 versions. Now Nepomuk just "scans" for changes, without indexing anything.
 
;Nepomuk accesses the disk too much on startup.:
 
:In 4.7 and newer this problem has been lessened thanks to a throttling mechanism implemented in the file indexer.


;My Nepomuk database has been corrupted. How do I clean it?
:A throttling mechanism implemented in the file indexer, versions after KDE SC 4.8 should no longer have this issue.


:In the extreme case your database is really corrupted and all other attempts have failed, you can delete the <tt>$KDEHOME/share/apps/nepomuk</tt> directory (where <tt>$KDEHOME</tt> is usually <tt>.kde</tt> or <tt>.kde4</tt>) while Nepomuk is not running. The database will be cleared, but you will also lose existing information such as tags, ratings and comments.
;My Search database has been corrupted. How do I clean it?


[[Category:System]]
:In the extreme case your database is really corrupted and all other attempts have failed, you can delete the <tt>$KDEHOME/share/apps/nepomuk</tt> directory (where <tt>$KDEHOME</tt> is usually <tt>.kde</tt> or <tt>.kde4</tt> in your home directory) while Nepomuk is not running. The database will be cleared, but you will also lose existing information such as tags, ratings and comments.


== Advanced troubleshooting ==
== Advanced troubleshooting ==
If Nepomuk has trouble indexing a file, in a terminal try running
{{Input|1=nepomukindexer ''/path/to/file''}}
and see if there's any useful output. If the file cannot be indexed, the indexer will print an error, but you will only see that error if you have debug messages for Nepomuk enabled (kdebugdialog). If the error is reproducible, please file a bug and upload the file along with the error.
[http://kdeatopensuse.wordpress.com/2011/11/09/debugging-nepomukvirtuosos-cpu-usage/ This blog post] explains how to turn on debugging output from the [[Glossary#Nepomuk|Nepomuk]] service. It also shows how to debug the CPU usage of '''Nepomuk''' and its storage backend.
[http://vhanda.in/blog/2012/02/virtuoso-going-crazy-/ This blog post] explains how to extract useful information for bug reports about the CPU usage of the '''Virtuoso''' backend.


==Compartir y privacidad==  
==Compartir y privacidad==  
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Este problema está siendo considerado y es un tema importante de investigación por parte de los investigadores de Nepomuk. Por el momento, estas preocupaciones sobre la privacidad, combinadas con retos técnicos, son la razón de que la información de Nepomuk sea privada. Ten la seguridad de que el equipo de Nepomuk hace todo lo posible para respetar tu privacidad.
Este problema está siendo considerado y es un tema importante de investigación por parte de los investigadores de Nepomuk. Por el momento, estas preocupaciones sobre la privacidad, combinadas con retos técnicos, son la razón de que la información de Nepomuk sea privada. Ten la seguridad de que el equipo de Nepomuk hace todo lo posible para respetar tu privacidad.


<span class="mw-translate-fuzzy">
== External links ==
:''Más información'':
 
::[http://en.wikipedia.org/wiki/Semantic_desktop Wikipedia (Inglés) - Semantic Desktop]
The new Search technology (post KDE Applications 4.13):
::[http://es.wikipedia.org/wiki/NEPOMUK  Wikipedia - NEPOMUK]  
* [http://dot.kde.org/2014/02/24/kdes-next-generation-semantic-search user information article on the dot]
::[http://nepomuk.semanticdesktop.org/xwiki/bin/view/Main1/ Página web de NEPOMUK]
* [http://community.kde.org/Baloo Developer information on community.kde.org]
::[http://nepomuk.kde.org/discover/user Sitio en KDE de NEPOMUK]
* [http://en.wikipedia.org/wiki/Semantic_desktop Wikipedia - Semantic Desktop]  
::[http://dot.kde.org/2009/12/10/exploring-new-nepomuk-features-mandriva-linux-2010 Artículo que explica Nepomuk en el DOT]
</span>


The old Search technology:
* [http://techbase.kde.org/Projects/Nepomuk Nepomuk pages for developers on KDE TechBase]
* [http://techbase.kde.org/Projects/Nepomuk Nepomuk pages for developers on KDE TechBase]
* [http://nepomuk.kde.org/discover/user NEPOMUK KDE site]
* [http://nepomuk.kde.org/discover/user NEPOMUK KDE site]
* [http://en.wikipedia.org/wiki/Semantic_desktop Wikipedia - Semantic Desktop]
* [http://en.wikipedia.org/wiki/NEPOMUK_(framework)  Wikipedia - NEPOMUK Framework]  
* [http://en.wikipedia.org/wiki/NEPOMUK_(framework)  Wikipedia - NEPOMUK Framework]  
* [http://nepomuk.semanticdesktop.org/nepomuk/ NEPOMUK website]
* [http://nepomuk.semanticdesktop.org/nepomuk/ NEPOMUK website]
* [http://dot.kde.org/2009/12/10/exploring-new-nepomuk-features-mandriva-linux-2010 article explaining Nepomuk on the DOT]
* [http://dot.kde.org/2009/12/10/exploring-new-nepomuk-features-mandriva-linux-2010 article explaining Nepomuk on the DOT]
* [http://kdenepomukmanual.wordpress.com Getting started user manual]


[[Category:Sistema/es]]
[[Category:Sistema/es]]

Latest revision as of 05:10, 9 May 2018

Semantic Search

The aim of this page is not to fully explain KDE's Semantic Search technology and every detail, but to give a short overview, some examples, share the vision behind it and link to relevant information on the web.

Baloo is the next generation of semantic search

From KDE Applications 4.13 onwards, the 'Baloo' file indexing and file search framework replaces Nepomuk. Read details on the changes for Applications 4.13 here. Semantic Search no longer uses a single, big database, but separate, specialized databases for each type of data. The new search databases are in $HOME/.local/share/baloo. If you upgraded to KDE Applications 4.13 from an earlier KDE release, you can delete $KDEHOME/share/apps/nepomuk.

Breve explicación

As the Glossary mentions, Semantic Search is about classification, organisation and presentation of data. It is not an application, but a component which can be used by developers within applications.

Try out in Dolphin

For example, the Dolphin file manager makes use of Search. In KDE Applications versions prior to 4.13 Semantic Search must be enabled from System settings -> Desktop search. The information sidebar of Dolphin (Control -> Panels -> Information, or press F11) presents information extracted by Search about the selected file, and also allows you to assign tags, ratings and comments to files. This information is then stored and indexed by Search. You can then search for metadata using the navigation bar in Dolphin. Click to Find, or press Ctrl+F, and search for file names or file contents.


Funcionalidades

KDE's Semantic Search offers several 'layers' of functionality to applications. The first and most simple of those is manual tagging, rating and commenting, as used in Dolphin. This helps you to find your files faster, but is also a lot of work.

To make finding files containing text easier, Search offers a second functionality: indexing the text of files. You can find files by entering some words which you know are in there, or just (part of) their title.

The third layer is a very complex one, and the reason why the underlying technology, Nepomuk, was conceived as a research project of several companies and universities in the European union. This is where you will find difficult words like 'semantic desktop' and 'ontologies'. Basically, it is about context and relationships.

Indexing files

Search does not index every file on the hard drive. Its default configuration in most Linux distributions excludes some common patterns for backup files and configuration directories. You can change this in System Settings -> Desktop Search. Add folders to be excluded. If you want to turn off indexing of files entirely, just add your home folder there.

In System Settings you can also control whether Search indexes files on removable media such as USB drives and CD-ROMs. In KDE Applications 4.13 this is not available, removable media are not indexed. Future versions are planned to reintroduce this functionality.

Ejemplos

Let me try to explain what Semantic Search offers using two examples. These features are not available fully yet - the base is there but application developers need to integrate this in their applications.

Relaciones

Digamos que has recibido una foto de un amigo tuyo, hace dos semanas, y la guardaste en algún lugar en tu ordenador. ¿Cómo encuentras ese archivo ahora? A menos que sepas la ubicación, no tiene buena pinta.

Now Semantic Search aims to help you. You know this file came from that friend of yours, your computer does not know. Search, however, can remember this relationship. Searching on the name of your friend will therefore pop up the photo!

Another potential relationship is between a web page you copied text from and the document you pasted it into, or two images showing the same car. Such relations can sometimes be extracted from the files themselves (you could analyze photos and see who or what is on there) or supplied by the applications involved (as in the above email example). This part of Search is still under heavy development, and needs integration in applications, so you can expect it to take a few more years to really shine.

All in all, this part of Semantic Search is about making search smart. Think about how Google tries to be smart with your searches: when you search for a hotel and a city name, it shows above the website results a google map showing hotels in the city you mentioned! It might even suggest a better name in case you made a spelling mistake. Google also tries to put the most relevant information on top of the list of results, using complex calculations on relationships (links) between websites. Semantic Search will be able to offer such smart results and order them on relevancy using relationship information.

Contexto

These relationships can not only help you while searching for files, but also have an influence on applications and what information they present. Note that this way of using Search is still more a vision than reality! Many of the components are in place, but it is not yet integrated in applications and the desktop as a whole.

Aquí tienes un ejemplo de como llevar la información contextual a tu escritorio puede ayudarte a trabajar de forma más eficiente.

Digamos que estás trabajando en terminar algunas notas que has tomado después de una reunión. Suena el teléfono y alguien te pide que si puedes buscar la hoja de cálculo con precios y adaptarla a un cliente. Después de algunas interrupciones más descubres que tu escritorio está lleno de archivos y ventanas...

Sería bueno poder organizar todo un poco mejor ¿verdad?

Enter 'activities'. These have been introduced in Plasma, and currently offer different 'desktops'. They are a bit like virtual desktops, except that the desktop itself changes, not the set of applications. Different widgets, background, things like that. Of course, since Plasma 4.3, each virtual desktop can have its own activity, bringing the two in sync.

Si las aplicaciones y el escritorio estuvieran al tanto de las actividades, podrías crear una actividad para cada una de las tareas en las que trabajes regularmente. Por tanto, si normalmente cambias a una hoja de cálculo con precios, puedes crear una actividad para eso: pon un elemento de Vista de Carpeta (o varios) en el escritorio, añade una calculadora y un elemento de tareas pendientes para seguir la pista de lo que aún debes cambiar. ¡Quizás incluso un elemento de carpetas de correo electrónico mostrando los correos con preguntas relacionadas con esa hoja de cálculo!

Tan pronto como alguien haga una pregunta sobre precios, cambias a estas actividad, y ya puedes trabajar con tu aplicación de hojas de cálculo. ¡Es consciente de tu actividad por lo que te muestra hojas de cálculo de precios recientes, no la reciente lista del inventario en la que estás trabajando en otra actividad! Kopete, la aplicación de chat, muestra a tus colegas que lo saben todo sobre los precios, puesto que son las personas con las que siempre hablas cuando trabajas en esta actividad.

Cuando acabes, vuelves a la otra actividad y una vez más todas las aplicaciones ajustarán su comportamiento a lo que estés haciendo.

Los beneficios de esta forma de trabajo basada en actividades van más allá de lo que puedas esperar en un principio. No solo te ayuda a encontrar tus archivos y contactos, también a conmutar tareas por sí mismo. El cerebro humano no es muy bueno con multitareas - a la mayoría de la gente le lleva unos minutos coger velocidad después de cambiar de tarea. El cambio de 'entorno' agiliza esto, incluso si está solo en la pantalla. ¡Compáralo con alegrarte de hacer las maletas para tus vacaciones!

Por supuesto, lo anterior es sobre todo relevante para la gente que trabaja con su ordenador en una oficina o en casa. Un jugador o un usuario casual probablemente no utilizarán estas actividades.

The scenario described above is already partially implemented in the Activities but much work is still left.

Frequently Asked Questions

The following is taken from a KDE forums post. Please feel free to add/remove/modify details if you have the time!

What is the Nepomuk Semantic Desktop, and the Strigi Desktop File Indexer?
Nepomuk and Strigi are technologies part of what delivers the abilities of the Semantic Search in KDE. Both are not used directly in the latest generation of KDE's Semantic Search (details), however their successors share much of their code and concepts. Semantic Search provides a way to organize, annotate and build relationships among the data (not only file name and content, but for example which applications used a certain file, or how it is tagged). A number of KDE applications and workspaces use this basic infrastructure to deliver features such as email tagging (KMail) or activity setup (Plasma).
The file indexing allows applications such as Dolphin to search for files based on content, name, or other meta-data (e.g. tags) associated to indexed files. Such an indexer can also index non-text files, such as PDFs, by accessing the meta-data contained in these files (author, publication information, etc.). Some KDE components ship additional "analyzers" for more file types.
Why do we need both Akonadi and Semantic Search? Aren't they doing the same thing?
In short, Akonadi provides a cache of PIM data like calendar items, contacts and email, which is used by applications like KMail and Korganizer but also the calendar build in Plasma. Semantic Search plugs in Akonadi to provide search functionality. How Baloo offers search is actually up to the application. In case of KDE PIM, Xapian is used to provide indexing and search.
How can I disable the semantic desktop?
File indexing can be disabled by adding the users' home folder to the System Settings -> Desktop Search -> Do not search in these locations list. The other functionality is part of the applications that use it and thus can't be disabled without crippling these applications. For example, to not have any search in KMail you'll have to simply remove KMail...

In versions of the KDE Applications before 4.13, Semantic Search would have components running separate from applications. This functionality could be disabled by unchecking Enable Nepomuk File Indexer in the Desktop Search section of System Settings. In case you want to turn off all semantic features, uncheck Enable Nepomuk Semantic Desktop. Notice that this will turn off search in Dolphin as well.

Notice that with the latter option some programs who use Semantic Search for meta-data will offer reduced functionality: for example KMail will not be able to tag mail, or Plasma activities will not offer additional features such as icons, or program data information.
Baloo/Semantic Search is eating 100% CPU! What do I do?
Just wait. Certain files are very hard or even impossible to Index. At the moment, this includes for example text files of over 50 megabyte. When Search finds these, it will try for a fixed time. When it fails, it will try to find out what file is broken and disable indexing it in the future. As it indexes files in batches of about 40, it has to find the problematic file by indexing that bunch in parts: first half/second half, index problematic half in pieces again, until the file is found. This can take up to 30 minutes of heavy cpu usage. Unfortunately, while Baloo will not start to index a new batch of 40 files while on battery power, it continues to determine the broken file while on battery. This behaviour has been fixed in in KDE Applications 4.13.1 (it will stop indexing immediately when the power cord is unplugged) and the time the search for each file can take has been reduced to about 10 minutes. The Semantic Search team is working on improving the indexing tools to handle more difficult files.
Why do I have nepomukservicestub processes even though I've disabled Nepomuk?
It may be a bug. Please file a bug report with a complete description of your problem and the steps to trigger it.
File indexing of PDF/some other file types doesn't work.
PDF indexing is a known issue and it's being tracked in bug #231936. If you have issues with other files, open a bug, preferably adding a sample file that shows the problem.
The program nepomukservicestub crashes at startup.
A large number of fixes for crashes has been fixed for the 4.7.2 release of the KDE Workspaces and Applications. If you encounter more, please file bugs report with detailed instructions on how to reproduce the problem, as sometimes the developers are unable to trigger them in their test setups.
The virtuoso-t process hangs at 100% CPU.
Virtuoso-t is a key component of the old Semantic Search infrastructure and in some occasions the commands sent by the other components end up taking too much time (hence showing the effect of 100% CPU).

Virtuoso is no longer used by Semantic Search starting the Applications 4.13 release.

Sometimes Nepomuk consumes too much RAM.
Many of these problems have been fixed, in other cases however the developers are unable to reproduce the issues correctly. In this case, providing examples and test cases to bug reports increase the chances to get these bugs fixed.
Search accesses the disk too much on startup.
A throttling mechanism implemented in the file indexer, versions after KDE SC 4.8 should no longer have this issue.
My Search database has been corrupted. How do I clean it?
In the extreme case your database is really corrupted and all other attempts have failed, you can delete the $KDEHOME/share/apps/nepomuk directory (where $KDEHOME is usually .kde or .kde4 in your home directory) while Nepomuk is not running. The database will be cleared, but you will also lose existing information such as tags, ratings and comments.

Advanced troubleshooting

Compartir y privacidad

Solo quiero añadir una cosa más antes de indicar otras fuentes de información: intercambio de los datos de Nepomuk. Sería genial si tus etiquetas, puntuaciones y comentarios pudieran ser compartidos con otros cuando les envías los archivos. Sin embargo, si has etiquetado a un contacto con alguna etiqueta embarazosa ('aburrido en la cama') y le envías esa información de contacto personal a un amigo en común es probable que no quieras enviarle también esa etiqueta...

Este problema está siendo considerado y es un tema importante de investigación por parte de los investigadores de Nepomuk. Por el momento, estas preocupaciones sobre la privacidad, combinadas con retos técnicos, son la razón de que la información de Nepomuk sea privada. Ten la seguridad de que el equipo de Nepomuk hace todo lo posible para respetar tu privacidad.

External links

The new Search technology (post KDE Applications 4.13):

The old Search technology: