The LOD2 Consortium partners bring the essential know-how and software, which is necessary to build the LOD2 Stack. In particular, we have considered existing state-of-the-art software components developed by the LOD2 members which are briefly introduced in the following paragraphs. All contributed software is freely available under an Open Source license. A webinar serie is organised around the LOD2 stack. This is a convenient way to get in touch with the LOD2 Stack.
Technology Stack
Technology Stack
LOD2 Technology Stack Projects
OntoWiki
OntoWiki is a tool providing support for agile, distributed knowledge engineering scenarios. It facilitates the visual presentation of a knowledge base as an information map, with different views on instance data. It enables intuitive authoring of semantic content, with an inline editing mode for editing RDF content, similar to WYSIWIG for text documents.
PoolParty
PoolParty is a thesaurus management system and a SKOS editor for the Semantic Web including text mining and linked data capabilities. The system helps to build and maintain multilingual thesauri providing an easy-to-use interface. PoolParty server provides semantic services to integrate semantic search or recommender systems into systems like CMS, DMS, CRM or Wikis.
Sig.ma
Sig.ma is a tool to explore and leverage the Web of Data. At any time, information in Sigma is likely to come from multiple, unrelated Websites – potentially any website that embeds information in RDF, RDFa or Microformats (standards for the Web of Data). Sig.ma is a semantic web browser as well as an embeddable widget and also provides a Semantic Web API.
Comprehensive Knowledge Archive Network (CKAN)
CKAN is a registry or catalogue system for datasets or other "knowledge" resources. CKAN aims to make it easy to find, share and reuse open content and data, especially in ways that are machine automatable.
D2R Server
D2R Server is a tool for publishing relational databases on the Semantic Web. It enables RDF and HTML browsers to navigate the content of the database, and allows applications to query the database using the SPARQL query language.
DBpedia Extraction
DBpedia is a community effort to extract structured information from Wikipedia and to make this information available on the Web. It currently already contains a tremendous amount of valuable knowledge extracted from Wikipedia. The DBpedia knowledge base will be used for evaluation LOD2’s interlinking, fusing, aggregation and visualization components. The DBpedia multi-domain ontology will be used as background-knowledge for the LOD2 applications (WP7, WP8 and WP9), and as an alignment and annotation ontology for LOD in general.
DL-Learner
DL-Learner is a tool for supervised Machine Learning in OWL and Description Logics. It can learn concepts in Description Logics (DLs) from user-provided examples. Equivalently, it can be used to learn classes in OWL ontologies from selected objects. It extends Inductive Logic Programming to Descriptions Logics and the Semantic Web. The goal of DL-Learner is to provide a DL/OWL-based machine learning tool to solve supervised learning tasks and support knowledge engineers in constructing knowledge and learning about the data they created.
MonetDB
MonetDB is an open-source high-performance database system that allows to store relational, XML and RDF data, downloadable from monetdb.cwi.nl. While being well-known for its columnar architecture and CPU-cache optimizing algorithms, the crucial aspect leveraged in the scope of this project is its unique run-time query optimization framework which provides a unique environment to crack the recursive-correlated-self-join queries caused by semantic web queries to triple stores.
SemMF
SemMF is a flexible framework for calculating semantic similarity between objects that are represented as arbitrary RDF graphs. The framework allows taxonomic and non-taxonomic concept matching techniques to be applied to selected object properties. Moreover, new concept matchers are easily integrated into SemMF by implementing a simple interface, thus making it applicable in a wide range of different use case scenarios
Silk Framework
The Silk Linking Framework supports data publishers in setting explicit RDF links between data items within different data sources. Using the declarative Silk - Link Specification Language (Silk-LSL), developers can specify which types of RDF links should be discovered between data sources as well as which conditions data items must fulfil in order to be interlinked. These link conditions may combine various similarity metrics and can take the graph around a data item into account, which is addressed using an RDF path language.
Sindice
Sindice is a state of the art infrastructure to process, consolidate and query the Web of Data. Sindice collates these billions of pieces of metadata into an coherent umbrella of functionalities and services.
Sparallax
Sparallax is a faceted browsing interface for SPARQL endpoints, based on Freebase Parallax. This demonstrator showcases the benefits of intelligent browsing of Semantic Web data and represents a good starting point for LOD2 interfaces developed in WP 5.
Triplify
Triplify provides a building block for the “semantification” of Web applications. As a plugin for Web applications, it reveals the semantic structures encoded in relational databases by making database content available as RDF, JSON or Linked Data. Triplify makes Web applications easier mashable and lays the foundation for next-generation, semantics-based Web searches.
OpenLink Virtuoso
Virtuoso is a knowledge store and virtualization platform that transparently integrates Data, Services, and Business Processes across the enterprise. Its product architecture enables it to deliver traditionally distinct server functionality within a single system offering along the following lines: Data Management & Integration (SQL, XML and EII), Application Integration (Web Services & SOA), Process Management & Integration (BPEL), Distributed Collaborative Applications. The open-source data integration server and the highly efficient and scalable RDF triple store implementation in Virtuoso will be the basis for the knowledge store component in the LOD2 Stack.
WIQA
The Web Information Quality Assessment Framework is a set of software components that empowers information consumers to employ a wide range of different information quality assessment policies to filter information from the Web. Information providers on the Web have different levels of knowledge, different views of the world and different intensions. Thus, provided information may be wrong, biased, inconsistent or outdated. Before information from the Web is used to accomplish a specific task, its quality should be assessed according to task-specific criteria.
LIMES
LIMES is a link discovery framework for the Web of Data. It implements time-efficient approaches for large-scale link discovery based on the characteristics of metric spaces. It is easily configurable via a web interface. It can also be downloaded as standalone tool for carrying out link discovery locally. In addition the Colanut GUI implements mechanisms for the automatic suggestion of link configurations.
Testimonials
Dr. Mateja Verlič (Zemanta d.o.o., R&D)
We read a lot about people doing important things, however this time we – LOD2 partners – are the ones changing the history of Web by revolutionizing information use and reuse, contributing to semantic data standards and pushing the limits of almost every WWW-related aspect (sc… read
Dr. Jens Lehmann (Universität Leipzig, Research Group Leader)
The size and number of Semantic Web knowledge bases published as Linked Open Data has been growing tremendously over the past years. The LOD2 project will be a key factor for sustaining this momentum. More importantly, the quality of knowledge bases and the scalability of methods accessing… read
Jindřich Mynarz (University of Economics, Czech Republic)
Apart from being legally open, linked open data is an open technology. Due to its non-exclusive, non-proprietary, well-formalized, and standards-based nature, linked open data supports a wide spectrum of uses. It does not exclude any application from using it and thus it is open to be mixe… read
Dr. Mladen Stanojevic (Institute Mihajlo Pupin, Serbia)
The richness of any semantic model and the usability of represented data is dependent on the links between them. LOD2 is an important step in this direction that will enable an efficient exploration and processing of vast quantity of open data on the Web.
readMun Yong Yi (Korea Advanced Institute of Science and Technology (KAIST))
Data becomes more meaningful and powerful as they are linked and integrated. As I learn more about what LOD can do, I am convinced that it will not only change the future of the Internet but also the quality of human life. I am glad that I am participating in this project, which will defin… read
Orri Erling (OpenLink Software, Virtuoso Program Manager)
Value from information increasingly depends on integration. RDF is a great model for this. LOD2 will make RDF a cost competitive alternative in the database space, without compromising ad hoc flexibility and expressive power. read
Vojtech Svatek (University of Economics, Czech Republic)
As researcher in ontological engineering, I am excited to see LOD2 provide tools that make the generation of semantically structured data easy and thus widespread. I believe that ontological research is deemed to build upon the world views already expressed by means of simpl… read
Andreas Blumauer (Semantic Web Company, CEO)
15 years ago we all were excited when we published HTML for the first time and it didn't take a long time until all of us were "on the internet". Now we are starting to publish data on the web. Based on semantic web technologies professional data management will be possible in distributed … read
Kingsley Idehen (OpenLink Software, CEO)
Three years ago, OpenLink Software enthusiastically contributed the prowess of Virtuoso to the grassroots effort that lead to DBpedia and the Linked Open Data cloud that coalesced around it. Today, we are both honored and enthusiastic about Virtuoso's critical infrastructure role in this n… read
Bastiaan Deblieck (TenForce, Partner and Business Development Manager)
An internet of data opens up tremendous opportunities for our corporate and government customers. We intend to be on the forefront of this evolution. read
Christian Dirschl (Wolters Kluwer, Content Architect)
Linked (Open) Data will change the existing publishing paradigms! Creating high quality content for professional usage will remain an important factor in future publishing, but additional access points and new usage environments will equally define its success. read
Dr. Giovanni Tummarello (National University of Ireland, Galway, Research Unit Leader)
Semantic Markups on the Web could drive information reuse to enable scenarios and applications which we can now only dream of. The idea is extraordinarely compelling, but we know now it won't simply realize itself. The LOD2 project is now a great opportunity for inspired and coordinated re… read
Gregory Grefenstette (Exalead, Chief Science Officer)
Enterpise search is all about providing correct, complete, and appropriate information to the employee and decision maker. LOD2 promises to not only allow internal company information to be linked up to the growing amount of Open Data on the web, but to also provide the mechanisms for val… read
Hugh Williams (OpenLink Software)
It is exciting to see the LOD2 project finally kick off in its quest to take the Linked Open Data cloud to the next level of scalability, performance and integration for the exploitation of the Web as a viable platform for enterprise level data and information integration. read
Martin Kaltenböck (Semantic Web Company, CFO)
Linked (Open) Data technologies offer a new way of data integration for the enterprise! Smooth interoperability between internal data sets can reduce costs as well as the enrichment of these data sets by external data can support new market intelligence paradigms for a better decision making. read
Dr. Peter Boncz (Centrum Wiskunde & Informatica)
The publishing of ever more datasets by e.g. governments adds value for many key applications including business intelligence, which will drive the Linked Open Data (LOD) paradigm going forward. In the LOD2 project, CWI is working to increase the scalability and performance of querying int… read
Dr. Sören Auer (Universität Leipzig, LOD2 coordinator)
The Linked Data paradigm is a simple and efficient way for integration of heterogeneous information on the Web. Ultimately, we will, for example, be able to search for a new appartment and a close-by available spot in child care in one go. read
Tassilo Pellegrini (Semantic Web Company, R&D)
Semantic interoperability changes the technological and economic nature of metadata opening up exciting opportunities for value creation in various comercial and non-commercial areas. Linked Data is the blueprint for this new ecosystem and it will change the way we think about and use the web today. read
Wouter Dewanckel (TenForce, WP Project Leader)
It is an honor to take part in this challenging integration project to create solutions that can generate business value out of emerging technologies. read