Contact at or 8097636691
Responsive Ads Here

Wednesday, 31 January 2018

Bootstrapping Ontologies for Web Services(2012)

Bootstrapping Ontologies for Web Services(2012)

Ontologies have become the de-facto modeling tool of choice, employed in many applications and prominently in the semantic web. Nevertheless, ontology construction remains a daunting task. Ontological bootstrapping, which aims at automatically generating concepts and their relations in a given domain, is a promising technique for ontology construction. Bootstrapping an ontology based on a set of predefined textual sources, such as web services, must address the problem of multiple, largely unrelated concepts. In this paper, we propose an ontology bootstrapping process for web services. We exploit the advantage that web services usually consist of both WSDL and free text descriptors. The WSDL descriptor is evaluated using two methods, namely Term Frequency/Inverse Document Frequency (TF/IDF) and web context generation. Our proposed ontology bootstrapping process integrates the results of both methods and applies a third method to validate the concepts using the service free text descriptor, thereby offering a more accurate definition of ontologies. We extensively validated our bootstrapping method using a large repository of real-world web services and verified the results against existing ontologies. The experimental results indicate high precision. Furthermore, the recall versus precision comparison of the results when each method is separately implemented presents the advantage of our integrated bootstrapping approach.
Ontology creation and evolution and in particular on schema matching. Many heuristics were proposed for the automatic matching of schema and several theoretical models were proposed to represent various aspects of the matching process such as representation of mappings between Ontologies. However, all the methodologies described require comparison between existing Ontologies.
·        Previous work on ontology bootstrapping focused on either a limited domain or expanding an existing ontology.
·        UDDI registries have some major flaws. In particular, UDDI registries either are publicly available and contain many obsolete entries or require registration that limits access. In either case, a registry only stores a limited description of the available services.
The ontology bootstrapping process is based on analyzing a Web service using three different methods, where each method represents a different perspective of viewing the Web service. As a result, the process provides a more accurate definition of the ontology and yields better results. In particular, the Term Frequency/ Inverse Document Frequency (TF/IDF) method analyzes the Web service from an internal point of view, i.e., what concept in the text best describes the WSDL document content. The Web Context Extraction method describes the WSDL document from an external point of view, i.e., what most common concept represents the answers to the Web search queries based on the WSDL content. Finally, the Free Text Description Verification method is used to resolve inconsistencies with the current ontology.
The web service ontology bootstrapping process proposed in this paper is based on the advantage that a web service can be separated into two types of descriptions:
1) The Web Service Description Language (WSDL) describing “how” the service should be used and
2) A textual description of the web service in free text describing “what” the service does. This advantage allows bootstrapping the ontology based on WSDL and verifying the process based on the web service free text descriptor.
·        Data Extraction
·        Token Extraction
·        Term Frequency/IDF Analysis
·        Web context extraction
·        Ontology Evolution
Data Extraction:
In this module we develop the data extraction process using Whois. Whois is a Web service that allows domain details to be identified by based on the domain name .It maintains a web services related with operations and services.
Token Extraction:
In this module we develop the token extraction process using WSDL (Web Service Description Language). WSDL document with the token list bolded. The extracted token list serves as a baseline. These tokens are extracted from the WSDL document of a Web service Whois. The service is used as an initial step in our example in building the ontology. Additional services will be used later to illustrate the process of expanding the ontology.
Term Frequency/IDF Analysis:
Term Frequency/Inverse Document Frequency analysis is made in this module. TF/IDF is applied here to the WSDL descriptors. By building an independent corpus for each document, irrelevant terms are more distinct and can be thrown away with a higher confidence. To formally define TF/IDF, we start by defining frequency as the number of occurrences of the token within the document descriptor.
Web context extraction:
In this module, we develop the web context extraction process. Where, the Web pages clustering algorithm is based on the concise all pairs profiling (CAPP) clustering method. This method approximates profiling of large classifications. It compares all classes’ pair wise and then minimizes the total number of features required to guarantee that each pair of classes is contrasted by at least one feature.
Ontology Evolution:
Ontology evolution is the last module where, the descriptor is further validated using the textual service descriptor. The analysis is based on the advantage that a Web service can be separated into two descriptions: the WSDL description and a textual description of the Web service in free text. The WSDL descriptor is analyzed to extract the context descriptors and possible concepts as described.
•         System                 : Pentium IV 2.4 GHz.
•         Hard Disk            : 40 GB.
•         Floppy Drive       : 1.44 Mb.
•         Monitor                : 15 VGA Colour.
•         Mouse                  : Logitech.
•         Ram                     : 512 Mb.
•         Operating system           : - Windows XP.
•         Coding Language :  J2EE
•         Data Base             :  MYSQL

No comments:

Post a Comment