Research And Application Of Marine Ecology Ontology Modeling

The 21st century is the century of ocean. Ocean provides abundant food and mineral resources for human beings. It is the basis for human survival and development. Ocean is a large thermal reservoir to accommodate the heat. The efficiency of ocean carbon cycle to global climate change has far-reaching impact. Humans began to explore the seas and oceans very early and gained the accumulation of knowledge, data and information. Since the British "Challenger" International Exploration of the Sea between 1872 and 1876 to create a true sense of the oceanographic research, there have been more and more of marine scientific research institutions, more and more advanced observation equipments, and more and more observation methods. So far, a variety of marine research institutions store a large number of marine data and information, which is important to guide further exploration about ocean.However, the data storage formats of these research institutions are not always consistent. That hinders the sharing of data. Marine metadata can solve this problem, by achieving inter-operability of marine data.But some of the research data and information has polysemy, synonyms, unclear terminology and so on. Metadata is not well to deal with these semantics. Therefore, we must find a new way to realize the semantic understanding.Ontology as a formal, explicit specification of a shared conceptualization captures the knowledge of related fields, and provides common understanding in the domain. It can represent concepts and the relationships among them. Semantic within ontology has advantages in many fields and has a wide range of applications, especially in the information retrieval. In these applications, usually a lightweight ontology is sufficient.However, the marine ecosystem is a very complex system, and the current ontology building method can hardly describe the semantic relationships of various biological factors and non-biological factors and the interaction among them. Meanwhile, the ocean is full of roles, such as predator and prey, producers and consumers. In addition, some entities can play multiple roles. For example, phytoplankton in photosynthesis acts as agent of main chemical reactions, but in the bacterial decomposition plays a role of the object of decomposition. So, to build a more comprising ontology with deep semantics, it is necessary to deal with roles.Role theory of Hozo can exactly describe these complex relationships. Mizoguchi Lab of Osaka University put forward the role theory referencing other researches, and base on the role theory, they developed a powerful visual ontology editing tool named Hozo. This research is also based on the role theory, and Hozo is used to build marine ecology ontology.This research work has two parts. Firstly, by using the role theory, we establish a model of marine ecology ontology, and model the core concepts of this ontology with Hozo. Secondly, based on this ontology, an optimized information retrieval system named OASIS is developed. Experiments show that the system improves the retrieval results of traditional search engines.The main content and organization of this paper are as follows:Chapter 1 describes the research background, research significance, and historical overview of the application of ontology in marine field.Chapter 2 describes the definition, classification, description language, construction methods and tools of ontology. The most recently researches on ontology are also described.Chapter 3 introduces the theory of role modeling which constitutes the basis of Hozo, an ontology editor. The architecture of Hozo and some related concepts are also presented.Chapter 4 introduces the basic knowledge of marine ecosystems, and then describes the marine ecological factors and their impacts in the marine environment by using Hozo development tools and role theory.In chapter 5, a marine ecosystem construction model based on ontology engineering is proposed subsequently. The process of the construction of the marine ecosystem ontology and some techniques used in the construction are also presented.Chapter 6 describes the structure and the optimization strategy of the information retrieval system OASIS. By using the ontology constructed in chapter 5, some experiments are conducted upon traditional search engine and OASIS. Experiments show that the OASIS system improves the precision of the search result in marine field. By using a parallel processing framework named JPPF, we make the OASIS system do retrieval tasks in a distributed parallel way. The acceleration of ontology parsing and searching is analyzed. Chapter 7 concludes this thesis by summarizing the results, problems and deficiencies about this paper. Some future works are also discussed.