Misplaced Pages

#802197

71-487: Late in the year 1999 through early 2000, with funding from the Japan Science and Technology Corporation (JST), Hiroaki Kitano and John C. Doyle assembled a small team of researchers to work on developing better software infrastructure for computational modeling in systems biology . Hamid Bolouri was the leader of the development team, which consisted of Andrew Finney, Herbert Sauro, and Michael Hucka. Bolouri identified

142-487: A PhD in computer science from Kyoto University in 1991. His PhD thesis in machine translation was titled "Speech-to-speech translation: a massively parallel memory-based approach". His work includes a broad spectrum of publications in artificial intelligence and interactomics. From 1988 to 1994, Kitano was a visiting researcher at the Center for Machine Translation at Carnegie Mellon University . At Sony, Kitano started

213-410: A labeled , directed multigraph . This makes an RDF data model better suited to certain kinds of knowledge representation than other relational or ontological models. As RDFS , OWL and SHACL demonstrate, one can build additional ontology languages upon RDF. The initial RDF design, intended to "build a vendor-neutral and operating system- independent system of metadata", derived from

284-452: A Group Director of the Laboratory for Disease Systems Modeling at and RIKEN Center for Integrative Medical Sciences; and a professor at Okinawa Institute of Science and Technology (OIST). Kitano is known for developing AIBO , and the robotic world cup tournament known as Robocup . Kitano graduated from International Christian University with a B.A. in physics in 1984. He received

355-579: A URI could represent absolutely anything. However, there is broad agreement that a bare URI (without a # symbol) which returns a 300-level coded response when used in an HTTP GET request should be treated as denoting the internet resource that it succeeds in accessing. Therefore, producers and consumers of RDF statements must agree on the semantics of resource identifiers. Such agreement is not inherent to RDF itself, although there are some controlled vocabularies in common use, such as Dublin Core Metadata, which

426-875: A contribution to the Systems Biology Markup Language (SBML). Kitano has served as a scientific advisor for a number of companies, including Alstom , Segway Japan and Mitsubishi Chemical Holdings . He was awarded the IJCAI Computers and Thought Award in 1993 and the Nature Award for Creative Mentoring in Science in 2009. He was elected a Fellow of the Association for the Advancement of Artificial Intelligence in 2021. Resource Description Framework The Resource Description Framework ( RDF )

497-617: A facility to use nested annotations within SBML's annotation format (an annotation format that is based on a subset of RDF ). SBML is sometimes incorrectly assumed to be limited in scope only to biochemical network models because the original publications and early software focused on this domain. In reality, although the central features of SBML are indeed oriented towards representing chemical reaction-like processes that act on entities, this same formalism serves analogously for many other types of processes; moreover, SBML has language features supporting

568-478: A new modular base for continued expansion of SBML's features and capabilities going into the future. SBML Level 2 Version 5 was published in 2015. This revision included a number of textual (but not structural) changes in response to user feedback, thereby addressing the list of errata collected over many years for the SBML Level ;2 Version 4 specification. In addition, Version 5 introduced

639-424: A node for the subject, (2) an arc from subject to object, representing a predicate, and (3) a node for the object. Each of these parts can be identified by a Uniform Resource Identifier (URI). An object can also be a literal value. This simple, flexible data model has a lot of expressive power to represent complex situations, relationships, and other things of interest, while also being appropriately abstract. RDF

710-529: A simple enzyme-kinetics model: As of February 2020, nearly 300 software systems advertise support for SBML. A current list is available in the form of the SBML Software Guide , hosted at SBML.org. SBML has been and continues to be developed by the community of people making software platforms for systems biology, through active email discussion lists and biannual workshops. The meetings are often held in conjunction with other biology conferences, especially

781-450: A single scope identifier to be associated with a statement that has not been assigned a URI, itself. Likewise named graphs in which a set of triples is named by a URI can represent context without the need to reify the triples. The predominant query language for RDF graphs is SPARQL . SPARQL is an SQL -like language, and a recommendation of the W3C as of January 15, 2008. The following

SECTION 10

#1732872146803

852-459: A small and large scale. This SBML package makes use of standard components from the SBML Level 3 core specification, including species and reactions, and extends them with additional attributes and structures to allow modelers to define such things as flux bounds and optimization functions. The Qualitative Models or " qual " package for SBML Level 3 was released in May 2013. This package supports

923-422: A software tool to interpret the model and translate the SBML form into whatever internal form the tool actually uses. A software package can read an SBML model description and translate it into its own internal format for model analysis. For example, a package might provide the ability to simulate the model by constructing differential equations and then perform numerical time integration on the equations to explore

994-450: A specification was formally released in August, 2013. The SBML Level 3 Layout package provides a specification for how to represent a reaction network in a graphical form. It is thus better tailored to the task than the use of an arbitrary drawing or graph. The SBML Level 3 package only deals with the information necessary to define the position and other aspects of a graph's layout;

1065-539: A statement can be associated with a context, named by a URI, in order to assert an "is true in" relationship. As another example, it is sometimes convenient to group statements by their source, which can be identified by a URI, such as the URI of a particular RDF/XML document. Then, when updates are made to the source, corresponding statements can be changed in the model, as well. Implementation of scopes does not necessarily require fully reified statements. Some implementations allow

1136-448: A type of database called a triplestore . The subject of an RDF statement is either a uniform resource identifier (URI) or a blank node , both of which denote resources . Resources indicated by blank nodes are called anonymous resources. They are not directly identifiable from the RDF statement. The predicate is a URI which also indicates a resource, representing a relationship. The object

1207-489: A universal language for quantitative models. SBML's purpose is to serve as a lingua franca —an exchange format used by different present-day software tools to communicate the essential aspects of a computational model. SBML can encode models consisting of entities (called species in SBML) acted upon by processes (called reactions ). An important principle is that models are decomposed into explicitly-labeled constituent elements,

1278-433: Is SHACL (Shapes Constraint Language). SHACL specification is divided in two parts: SHACL Core and SHACL-SPARQL. SHACL Core consists of a list of built-in constraints such as cardinality, range of values and many others. SHACL-SPARQL describes SPARQL-based constraints and an extension mechanism to declare new constraint components. Other non-standard ways to describe and validate RDF graphs include: The following example

1349-411: Is a URI, blank node or a Unicode string literal . As of RDF 1.1 resources are identified by Internationalized Resource Identifiers (IRIs); IRI are a generalization of URI. In Semantic Web applications, and in relatively popular applications of RDF like RSS and FOAF (Friend of a Friend), resources tend to be represented by URIs that intentionally denote, and can be used to access, actual data on

1420-469: Is a method to describe and exchange graph data. It was originally designed as a data model for metadata by the World Wide Web Consortium (W3C). It provides a variety of syntax notations and data serialization formats, of which the most widely used is Turtle (Terse RDF Triple Language). RDF is a directed graph composed of triple statements. An RDF graph statement is represented by: (1)

1491-477: Is a specification and associated Python tooling to interconvert SBML and the shorthand notation. The format was developed by the UK Newcastle systems biology group sometime before 2006. Its aim was to enable modelers to more rapidly create models without having to either write raw XML or use GUI tools. Two Python tools are provided, mod2sbml.py and sbml2mod.py. The libSBML package for Python is required to assist in

SECTION 20

#1732872146803

1562-615: Is also available via the Tellurium package. More recently, a JavaScript/WASM version has been generated which allows the Antimony language to be used on the web. The website tool makesbml uses the Javascript version. Antimony supports SBML Level 3, version 2. Antimony also supports the following SBML packages: Hierarchical Model Composition, Flux Balance Constraints, and Distributions. The following example illustrates Antimony being used to describe

1633-595: Is an example of a SPARQL query to show country capitals in Africa, using a fictional ontology: Other non-standard ways to query RDF graphs include: SHACL Advanced Features specification (W3C Working Group Note), the most recent version of which is maintained by the SHACL Community Group defines support for SHACL Rules, used for data transformations, inferences and mappings of RDF based on SHACL shapes. The predominant language for describing and validating RDF graphs

1704-511: Is annotated and linked to relevant data resources such as publications, databases of compounds and pathways, controlled vocabularies, and more. With annotations, a model becomes more than simply a rendition of a mathematical construct—it becomes a semantically-enriched framework for communicating knowledge. SBML is defined in Levels : upward-compatible specifications that add features and expressive power. Software tools that do not need or cannot support

1775-410: Is based on the idea of making statements about resources (in particular web resources) in expressions of the form subject – predicate – object , known as triples . The subject denotes the resource; the predicate denotes traits or aspects of the resource, and expresses a relationship between the subject and the object . For example, one way to represent the notion "The sky has

1846-534: Is being undertaken such that specifications are reviewed and implementations attempted during the development process. Once a specification is stable and there are two implementations that support it, the package is considered accepted. The packages detailed above have all reached the acceptance stage. The table below gives a brief summary of packages that are currently in the development phase. A model definition in SBML Levels 2 and 3 consists of lists of one or more of

1917-598: Is considered valid.) Version 4 was finalized after the SBML Forum meeting held in Gothenburg , Sweden, as a satellite workshop of ICSB 2008 in the fall of 2008. SBML Level 3 Version 1 Core was published in final form in 2010, after prolonged discussion and revision by the SBML Editors and the SBML community. It contains numerous significant changes in syntax and constructs from Level 2 Version 4, but also represents

1988-575: Is done in software development and other engineering fields. The specification was the culmination of years of discussion by a wide number of people. The Flux Balance Constraints package (nicknamed " fbc ") was first released in February, 2013. Import revisions were introduced as part of Version 2, released in September, 2015. The " fbc " package provides support for constraint-based modeling, frequently used to analyze and study biological networks on both

2059-515: Is partially mapped to a URI space for use in RDF. The intent of publishing RDF-based ontologies on the Web is often to establish, or circumscribe, the intended meanings of the resource identifiers used to express data in RDF. For example, the URI: http://www.w3.org/TR/2004/REC-owl-guide-20040210/wine#Merlot is intended by its owners to refer to the class of all Merlot red wines by vintner (i.e., instances of

2130-401: Is rather a URI reference , containing the '#' character and ending with a fragment identifier . The body of knowledge modeled by a collection of statements may be subjected to reification , in which each statement (that is each triple subject-predicate-object altogether) is assigned a URI and treated as a resource about which additional statements can be made, as in " Jane says that John

2201-521: Is some resource or literal. More statements about the original statement may also exist, depending on the application's needs. Borrowing from concepts available in logic (and as illustrated in graphical notations such as conceptual graphs and topic maps ), some RDF model implementations acknowledge that it is sometimes useful to group statements according to different criteria, called situations , contexts , or scopes , as discussed in articles by RDF specification co-editor Graham Klyne . For example,

SBML - Misplaced Pages Continue

2272-478: Is taken from the W3C website describing a resource with statements "there is a Person identified by http://www.w3.org/People/EM/contact#me, whose name is Eric Miller, whose email address is e.miller123(at)example (changed for security purposes), and whose title is Dr." The resource "http://www.w3.org/People/EM/contact#me" is the subject. The objects are: The subject is a URI. The predicates also have URIs. For example,

2343-431: Is the author of document X". Reification is sometimes important in order to deduce a level of confidence or degree of usefulness for each statement. In a reified RDF database, each original statement, being a resource, itself, most likely has at least three additional statements made about it: one to assert that its subject is some resource, one to assert that its predicate is some resource, and one to assert that its object

2414-482: Is used as a foundation for RDF Schema , where it is extended. Several common serialization formats are in use, including: RDF/XML is sometimes misleadingly called simply RDF because it was introduced among the other W3C specifications defining RDF and it was historically the first W3C standard RDF serialization format. However, it is important to distinguish the RDF/XML format from the abstract RDF model itself. Although

2485-516: The Specifications page of SBML.org. Development of SBML Level 3 has been proceeding in a modular fashion. The Core specification is a complete format that can be used alone. Additional Level 3 packages can be layered on to this core to provide additional, optional features. The Hierarchical Model Composition package, known as " comp ", was released in November 2012. This package provides

2556-525: The University of Hertfordshire , UK. By this time, far more people were involved than the original group of SBML collaborators and the continued evolution of SBML became a larger community effort, with many new tools having been enhanced to support SBML. The workshop participants in 2002 collectively decided to revise the form of SBML in Level ;2. The first draft of the Level 2 Version 1 specification

2627-546: The University of Michigan . In 1999, the W3C published the first recommended RDF specification, the Model and Syntax Specification ("RDF M&S"). This described RDF's data model and an XML serialization. Two persistent misunderstandings about RDF developed at this time: firstly, due to the MCF influence and the RDF "Resource Description" initialism, the idea that RDF was specifically for use in representing metadata; secondly that RDF

2698-656: The 2nd Workshop on Software Platforms for Systems Biology, held in Tokyo , Japan, in November 2000 as a satellite workshop of the ICSB 2000 conference. After further revisions, discussions and software implementations, the Caltech team issued a specification for SBML Level 1, Version 1 in March 2001. SBML Level 2 was conceived at the 5th Workshop on Software Platforms for Systems Biology, held in July 2002, at

2769-488: The BIOSIM simulator. Like SBML-shorthand, Antimony provides a simplified text representation of SBML. It uses a minimum of punctuation characters which renders the text easier to read and understand. It also allows users to add comments. Antimony is implemented using C/C++ and Bison as the grammar parser. However, the distribution also includes Python bindings which can be installed using pip to make it easy to use from Python. It

2840-499: The International Conference on Systems Biology (ICSB). The community effort is coordinated by an elected editorial board made up of five members. Each editor is elected for a 3-year non-renewable term. Tools such as an online model validator as well as open-source libraries for incorporating SBML into software programmed in the C , C++ , Java , Python , Mathematica , MATLAB and other languages are developed partly by

2911-467: The RDF/XML format is still in use, other RDF serializations are now preferred by many RDF users, both because they are more human-friendly, and because some RDF graphs are not representable in RDF/XML due to restrictions on the syntax of XML QNames . With a little effort, virtually any arbitrary XML may also be interpreted as RDF using GRDDL (pronounced 'griddle'), Gleaning Resource Descriptions from Dialects of Languages. RDF triples may be stored in

SBML - Misplaced Pages Continue

2982-586: The SBML Team and partly by the broader SBML community. SBML is an official IETF MIME type, specified by RFC 3823. Hiroaki Kitano Hiroaki Kitano ( 北野 宏明 , born 1961 in Tokyo ) is a Japanese scientist . He is the head of the Systems Biology Institute (SBI); Senior Executive Vice President and Chief Technology Officer of Sony Group Corporation, Chief Executive Officer of Sony Research Inc. and Sony Computer Science Laboratories, Inc.;

3053-474: The SBML community. 2007 also saw the election of two more SBML Editors as part of the introduction of the modern SBML Editor organization in the context of the SBML development process. SBML Level 2 Version 4 was published in 2008 after certain changes in Level 2 were requested by popular demand. (For example, an electronic vote by the SBML community in late 2007 indicated a majority preferred not to require strict unit consistency before an SBML model

3124-645: The URI for each predicate: In addition, the subject has a type (with URI http://www.w3.org/1999/02/22-rdf-syntax-ns#type), which is person (with URI http://www.w3.org/2000/10/swap/pim/contact#Person). Therefore, the following "subject, predicate, object" RDF triples can be expressed: In standard N-Triples format, this RDF can be written as: Equivalently, it can be written in standard Turtle (syntax) format as: Or, it can be written in RDF/XML format as: Certain concepts in RDF are taken from logic and linguistics , where subject-predicate and subject-predicate-object structures have meanings similar to, yet distinct from,

3195-670: The W3C's Platform for Internet Content Selection (PICS), an early web content labelling system, but the project was also shaped by ideas from Dublin Core , and from the Meta Content Framework (MCF), which had been developed during 1995 to 1997 by Ramanathan V. Guha at Apple and Tim Bray at Netscape . A first public draft of RDF appeared in October 1997, issued by a W3C working group that included representatives from IBM , Microsoft , Netscape , Nokia , Reuters , SoftQuad , and

3266-492: The World Wide Web. But RDF, in general, is not limited to the description of Internet-based resources. In fact, the URI that names a resource does not have to be dereferenceable at all. For example, a URI that begins with "http:" and is used as the subject of an RDF statement does not necessarily have to represent a resource that is accessible via HTTP , nor does it need to represent a tangible, network-accessible resource — such

3337-430: The ability to include models as submodels inside another model. The goal is to support the ability of modelers and software tools to do such things as (1) decompose larger models into smaller ones, as a way to manage complexity; (2) incorporate multiple instances of a given model within one or more enclosing models, to avoid literal duplication of repeated elements; and (3) create libraries of reusable, tested models, much as

3408-445: The above URI each represent the class of all wine produced by a single vintner), a definition which is expressed by the OWL ontology — itself an RDF document — in which it occurs. Without careful analysis of the definition, one might erroneously conclude that an instance of the above URI was something physical, instead of a type of wine. Note that this is not a 'bare' resource identifier, but

3479-399: The additional details necessary to complete the graph—namely, how the visual aspects are meant to be rendered— are the purview of the separate SBML Level 3 package called Rendering (nicknamed " render "). As of November 2015, a draft specification for the " render " package is available, but it has not yet been officially finalized. Development of SBML Level 3 packages

3550-492: The color blue" in RDF is as the triple: a subject denoting "the sky", a predicate denoting "has the color", and an object denoting "blue". Therefore, RDF uses subject instead of object (or entity ) in contrast to the typical approach of an entity–attribute–value model in object-oriented design : entity (sky), attribute (color), and value (blue). RDF is an abstract model with several serialization formats (being essentially specialized file formats ). In addition

3621-454: The complexity of higher Levels can go on using lower Levels; tools that can read higher Levels are assured of also being able to interpret models defined in the lower Levels. Thus new Levels do not supersede previous ones. However, each Level can have multiple Versions within it, and new Versions of a Level do supersede old Versions of that same Level. There are currently three Levels of SBML defined. The current Versions within those Levels are

SECTION 50

#1732872146803

3692-569: The conversion. Currently, SBML-shorthand supports SBML Level 3, version 1. The following code is an example of SBML-shorthand being used to describe the simple enzyme-substrate mechanism. Antimony is based on an earlier DSL implemented in the Jarnac modeling application. That, in turn, was based on the SCAMP modeling application which ultimately drew inspiration from the DSL language developed by David Garfinkel for

3763-469: The creation of a portable file format for metabolic network models in the BioThermoKinetics (BTK) group. The same groups who attended the first Caltech workshop met again on April 28–29, 2000, at the first of a newly created meeting series called Workshop on Software Platforms for Systems Biology . It became clear during the second workshop that a common model representation format was needed to enable

3834-406: The development of SBML Level 2 Version 2, issued in September 2006. By this time, the team of SBML Editors (who reconcile proposals for changes and write a coherent final specification document) had changed and now consisted of Andrew Finney, Michael Hucka and Nicolas Le Novère. SBML Level 2 Version 3 was published in 2007 after countless contributions by and discussions with

3905-601: The development of the AIBO robotic pet. This research was developed further as the QRIO , a bipedal humanoid robot. The research behind AIBO and QRIO led to Kitano founding the RoboCup annual international robotics competition in 1997. The goal of RoboCup is to create a team of autonomous robotic footballers that would be able to beat the best team in the world, by 2050. Kitano has made significant contributions to Systems biology , including

3976-407: The direct expression of mathematical formulas and discontinuous events separate from reaction processes, allowing SBML to represent much more than solely biochemical reactions. Evidence for SBML's ability to be used for more than merely descriptions of biochemistry can be seen in the variety of models available from BioModels Database . SBML has three main purposes: SBML is not an attempt to define

4047-494: The exchange of models between software tools as part of any functioning interoperability framework, and the workshop attendees decided the format should be encoded in XML . The Caltech ERATO team developed a proposal for this XML-based format and circulated the draft definition to the attendees of the 2nd Workshop on Software Platforms for Systems Biology in August 2000. This draft underwent extensive discussion over mailing lists and during

4118-505: The following components: SBML is primarily a format for the exchange of systems biology models between software modeling tools or for archiving models in repositories such as BiGG , BioModels , or JWS Online . Since SBML is encoded in XML and in particular uses MathML for representing mathematics, the format is not human-readable. As a result, other groups have developed human-readable formats that can be converted to and from SBML. SBML shorthand

4189-456: The following: Open-source software infrastructure such as libSBML and JSBML allows developers to support all Levels of SBML their software with a minimum amount of effort. The SBML Team maintains a public issue tracker where readers may report errors or other issues in the SBML specification documents. Reported issues are eventually put on the list of official errata associated with each specification release. The lists of errata are documented on

4260-480: The model's dynamic behavior. Or, alternatively, a package might construct a discrete stochastic representation of the model and use a Monte Carlo simulation method such as the Gillespie algorithm . SBML allows models of arbitrary complexity to be represented. Each type of component in a model is described using a specific type of data structure that organizes the relevant information. The data structures determine how

4331-620: The need for a framework to enable interoperability and sharing between the different simulation software systems for biology in existence during the late 1990s, and he organized an informal workshop in December 1999 at the California Institute of Technology to discuss the matter. In attendance at that workshop were the groups responsible for the development of DBSolve, E-Cell, Gepasi, Jarnac, StochSim, and The Virtual Cell. Separately, earlier in 1999, some members of these groups also had discussed

SECTION 60

#1732872146803

4402-458: The nodes are the reachable states and the edges are the state transitions. The SBML layout package originated as a set of annotation conventions usable in SBML Level 2. It was introduced at the SBML Forum in St. Louis in 2004. Ralph Gauges wrote the specification and provided an implementation that was widely used. This original definition was reformulated as an SBML Level 3 package, and

4473-740: The particular encoding for resources or triples can vary from format to format. This mechanism for describing resources is a major component in the W3C's Semantic Web activity: an evolutionary stage of the World Wide Web in which automated software can store, exchange, and use machine-readable information distributed throughout the Web, in turn enabling users to deal with the information with greater efficiency and certainty . RDF's simple data model and ability to model disparate, abstract concepts has also led to its increasing use in knowledge management applications unrelated to Semantic Web activity. A collection of RDF statements intrinsically represents

4544-430: The representation of models where an in-depth knowledge of the biochemical reactions and their kinetics is missing and a qualitative approach must be used. Examples of phenomena that have been modeled in this way include gene regulatory networks and signaling pathways, basing the model structure on the definition of regulatory or influence graphs. The definition and use of some components of this class of models differ from

4615-472: The resulting model is encoded in XML. In addition to the elements above, another important feature of SBML is that every entity can have machine-readable annotations attached to it. These annotations can be used to express relationships between the entities in a given model and entities in external resources such as databases. A good example of the value of this is in BioModels Database, where every model

4686-414: The set of which resembles a verbose rendition of chemical reaction equations (if the model uses reactions) together with optional explicit equations (again, if the model uses these); the SBML representation deliberately does not cast the model directly into a set of differential equations or other specific interpretation of the model. This explicit, modeling-framework-agnostic decomposition makes it easier for

4757-459: The way that species and reactions are defined and used in core SBML models. For example, qualitative models typically associate discrete levels of activities with entity pools; consequently, the processes involving them cannot be described as reactions per se, but rather as transitions between states. These systems can be viewed as reactive systems whose dynamics are represented by means of state transition graphs (or other Kripke structures ) in which

4828-470: Was adopted as a W3C recommendation in 1999. The RDF 1.0 specification was published in 2004, and the RDF 1.1 specification in 2014. SPARQL is a standard query language for RDF graphs. RDF Schema (RDFS), Web Ontology Language (OWL) and SHACL (Shapes Constraint Language) are ontology languages that are used to describe RDF data. The RDF data model is similar to classical conceptual modeling approaches (such as entity–relationship or class diagrams ). It

4899-709: Was an XML format rather than a data model, and only the RDF/XML serialisation being XML-based. RDF saw little take-up in this period, but there was significant work done in Bristol , around ILRT at Bristol University and HP Labs , and in Boston at MIT . RSS 1.0 and FOAF became exemplar applications for RDF in this period. The recommendation of 1999 was replaced in 2004 by a set of six specifications: "The RDF Primer", "RDF Concepts and Abstract", "RDF/XML Syntax Specification (revised)", "RDF Semantics", "RDF Vocabulary Description Language 1.0", and "The RDF Test Cases". This series

4970-450: Was released in August 2002, and the final set of features was finalized in May 2003 at the 7th Workshop on Software Platforms for Systems Biology in Ft. Lauderdale , Florida. The next iteration of SBML took two years in part because software developers requested time to absorb and understand the larger and more complex SBML Level 2. The inevitable discovery of limitations and errors led to

5041-413: Was superseded in 2014 by the following six "RDF 1.1" documents: "RDF 1.1 Primer", "RDF 1.1 Concepts and Abstract Syntax", "RDF 1.1 XML Syntax", "RDF 1.1 Semantics", "RDF Schema 1.1", and "RDF 1.1 Test Cases". The vocabulary defined by the RDF specification is as follows: rdf:Statement , rdf:subject , rdf:predicate , rdf:object are used for reification (see below ). This vocabulary

#802197