[SkyPackage: From Finding Items to Finding A Skyline of Packages on the Semantic Web]

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Acknowledgement

I would take this opportunity to thank my research supervisor, family and friends for their support and guidance without which this research would not have been possible.

DECLARATION

I, [type your full first names and surname here], declare that the contents of this dissertation/thesis represent my own unaided work, and that the dissertation/thesis has not previously been submitted for academic examination towards any qualification. Furthermore, it represents my own opinions and not necessarily those of the University.

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Abstract

Semantic Web service descriptions are typically multi parameter constructs. Discovering semantically relevant services given a desirable service description is typically addressed by performing a pair wise, logic-based match between the requested and offered parameters. However, little or no attention is given to combining these partial results to compile the final list of candidate services. Instead, this is often done in an ad hoc manner, implying a priori assumptions regarding the user's preferences. In this paper, we focus on identifying the best candidate Semantic Web services given the description of a requested service. We model the problem as a skyline query, also known as the maximum vector problem, and we show how the service selection process can be performed efficiently. We consider different aspects of the service selection process, addressing both the requesters' and the providers' points of view. Experimental evaluation on real and synthetic data shows the effectiveness and efficiency of the proposed approach.

Table of Contents

INTRODUCTION6

Background7

Problem formulation8

LITERATURE REVIEW9

Related Work9

One Pass Algorithm14

Dual Progressive Algorithm15

Bottom-Up Algorithm18

Selecting Skyline Services for QoS based Web Service Composition19

Determining the Skyline Services22

Composing the Skyline Services22

Representative Skyline Services24

P-Dominant Service Skyline25

Experimental Evaluation31

Synthetic data33

Computing the p-dominant skyline using P-r-tree33

P-R tree34

Process of Skyline packaging34

Compiling a data set35

Selecting individuals35

Selecting loci36

Selection of age calibrations38

Skyline-plot methods39

Simulations39

Classic skyline39

Generalized skyline40

Bayesian multiple-change-point41

Bayesian skyline42

Interpretation of skyline plots43

Choosing a method44

RESEARCH METHODOLOGY45

Data Sources and Research Limitations45

Research Instruments46

Data Types46

Primary Data46

Secondary Data46

CONCLUSION47

SkyPackage: From Finding Items to Finding A Skyline of Packages on the Semantic Web

Introduction

Web services, as a key technology for realizing service oriented architectures, promise to enable interoperability and integration between heterogeneous systems and applications. The discovery and selection of the appropriate services to fulfill a given request constitutes a fundamental task in such architectures. However, current industry standards for describing and locating Web services (WSDL, UDDI) aim at describing the structure of the service interface and of the exchanged messages, limiting the discovery process to essentially keyword-based search. Even though interoperability at the syntactic level is a necessary requirement, the identification and selection of appropriate services should be done in terms of the semantics of the requested and offered capabilities. To this direction, the Semantic Web, through the use of ontologies, provides the means to enrich the service descriptions with semantic information, allowing software agents to reason about the terms in these descriptions. This is a significant step for increasing the precision of the discovery process, as well as for minimizing the required human intervention. Several approaches have been proposed for adding semantics to Web service descriptions, namely OWL-S, WSDL-S, ...