Browsing by Subject "Newt"

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    ItemOpen Access
    Efficient querying of SBGN maps stored in a graph database
    (2019-02) Karaca, Mustafa Enes
    Graph visualization is an important research area that endeavors to make graphs more understandable and easier to analyze. In various domains, graph visualization techniques and standards are developed to effectively analyze underlying graph based data. Systems Biology Graphical Notation (SBGN) is a standard language for modeling biological processes and pathways through graph visualization. Information about SBGN maps can be stored in XML based SBGNML files. libSBGN is a Java/C++ library for reading, writing SBGN-ML and manipulating SBGN maps in an object-oriented manner. Graph databases store data in terms of a graph structure consisting nodes and their relationships. Performing a computation on graph data stored in a graph database by traversals is more e cient than accessing tabled data in relational databases through costly join operations. Neo4j is a prominent graph database that provides a proprietary language named Cypher for querying stored graph data. Neo4j allows writing user defined procedures in Java as plugins to improve capabilities of Neo4j with third party Java libraries. With this thesis, we enable modeling SBGN maps in Neo4j graph database with support for compound structures. Using this SBGN data model in Neo4j, we developed graph based user defined procedures in Java using libSBGN as a plugin to Neo4j. These procedures were used to implement graph query algorithms, such as neighborhood, common stream, and paths between, along with helper functions such as populating a database from an SBGN map and loading an SBGN map from a graph database. These user defined procedures are designed to produce or consume SBGN-ML; hence, they can be used by any visualization tool which can import/export SBGN-ML text. Newt, a web based editor for viewing and diting SBGN maps, is such a tool making use of these procedures and hosting a local Neo4j instance by providing a web service to execute Cypher statements.
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    ItemOpen Access
    Semantic validation of biological maps in SBGN
    (2019-09) Çalış, Umut Utku
    Graph visualization is a research field where relational information is graphically represented in the form of graphs or networks. It is applicable in numerous areas from computer network systems, to biology, to software engineering. In such areas, graph visualization techniques provide effective visual analysis of graph based data. Systems Biology Graphical Notation (SBGN) facilitates a standard model for representing biological entities and their interactions by using graph visualization. SBGN-ML is an XML based format for keeping information about SBGN maps. libSBGN enables writing and reading SBGN-ML files in an easy manner and is meant to bring syntactic and semantic validation to SBGN maps. It is currently available in Java/C++ (libSBGN) and JavaScript (libSBGN.js) programming languages with varying support for aforementioned. libSBGN enables important syntactic and semantic correctness concepts for manipulating SBGN maps and converting SBGN-ML files into several other formats. Syntactic validation of SBGN-ML files involves using a simple XML Schema Definition (XSD) file. This validation checks whether files are in correct form or not. However, this XSD file does not enable checking against semantic rules. For semantic validation of such files, the Schematron language was developed providing higher level semantic rule controls. With this thesis, we first enabled high level semantic validation (schematron validation) of SBGN maps in libSBGN.js, which uses XSLT and transformation of process description maps in SBGN-ML files. By using Schematron rules which are written in XPath syntax and enabling human-readable messages of validation errors and source of errors, we developed an XSLT stylesheet. We obtained validation result report by transforming SBGN-ML files using this XSLT stylesheet. In the JavaScript version of libSBGN library, we used a web based XSLT processor for transformation; hence, this library is now available for providing schematron validation in any SBGN related software. Furthermore, we added schematron validation checks to Newt, a web based SBGN pathway editor, using the updated libSBGN.js library. With this addition, Newt is now able to show validation results not only in a human-readable message text for the current map but also highlights the invalid map objects graphically, and, where appropriate, suggests a way to fix the problem automatically.