Classification and automatic indexing in a persistent object environment

The goal of this project is to study classification and automatic indexing for multimedia data in the context of digital libraries. The general objectives are: (1) to propose methods for digital media classification and indexing and (2) to implement them effectively by using a persistent environment provided by object-oriented database systems

Content Repository in Object Oriented data model

The need for creating content repository stores for e-learning systems grows as the number of available materials increases. Moreover, along with the number of courses, the problem of describing them in a unified form appears. While there are standards used for strict classification of elearning content, the store model still seems to be based on preservative relational databases approach.In this paper we introduce an idea to represent the e-learning content management information in the well organized object-oriented form based on a prospective object-oriented database

Typesafe Dynamic Classification

Object-oriented systems rely on classification of objects as a basic principle. This classification can depend on the type of the object, or its state. Many systems, including almost all object-oriented programming languages, only support classification by type, making classes independent of state changes. Many application domains, however, use taxonomies based on classification by state. Views in database systems can achieve this kind of classification but object-oriented database systems do not accept these views as classes. The problem with classification by state is the need to reclassify objects after updates, and to maintain the type-safety in the presence of references to reclassified objects: if an object drops out of a class that a reference to it expects, then the reference is left ill-typed. Role models which allow explicit reclassification face the same problem. For SQL3, classification by state was considered but dropped in favour of mutability, substitutability, and static type checking; all four properties were considered incompatible but are not completely. Our proposal to handle the reclassification problem uses a powerful relationship mechanism instead of simple references. Relationships are multi-directional, thus allowing to find objects related to the reclassified one. We then either remove the link between the objects, or roll back the change that caused the reclassification. We also present an approach with less overhead that employs dynamic type checking. While the first approach allows to use views and role classes in the application schema, the second handles them for local variables in methods. We therefore combine both, which permits us to use view and role classes almost arbitrarily. This enables the important use of views in the schema to help maintaining consistency, as known from relational database systems. Finally, we discuss the combination of classification by properties, known as subclassing by constraining, and classification by type

Should EU Land Use and Land Cover Data be managed with a NoSQL Document Store?

Land cover (LC) is a scientific landscape classification based on physical properties of earth materials. This information is usually retrieved through remote sensing techniques (e.g. forest cover, urban, clay content, among others). In contrast, Land use (LU) is defined from an anthropocentric point of view. It describes how a specific area is used (e.g. it is usual to indicate whether a territory supports an intensive, extensive use or it is unused). Both geospatial layers are essential inputs in many socio-economic and environmental studies. The INSPIRE directive provides technical data specifications for harmonization and sharing of voluminous LU/ LC datasets across all countries of the EU. The INSPIRE initiative proposes Object-Oriented Modelling as a data modelling methodology. However, the most used Geographic Information Systems (GIS) are built upon relational databases. This may jeopardize LU/LC data usability, since GIS practitioners will eventually face the object-relational impedance mismatch. In this paper, the authors introduce the SIOSE database (Spanish Land Cover and Land Use Information System), which was the first implementation of an object-oriented land cover and Land-use datamodel, in line with the recommendation of the INSPIRE Directive, separating both themes. SIOSE data can be downloaded as relational database files, where information describing each single LU/LC object is divided among several related tables, so database queries can be complex and time consuming. The authors show these technical complexities through a computational experience, comparing SQL and NoSQL databases for querying spatial data downloaded from SIOSE. Finally, the authors conclude that NoSQL geodatabases deserve to be further explored because they could scale for LU/LC data, both horizontally and vertically, better than relational geodatabases, improving usability and making the most of the EU harmonization efforts

Object-Oriented Software Representation of Polymer Materials Information in Engineering Design

The software application POISE, Polymer Objects in a Smalltalk™ Environment, integrates knowledge representation, user interfaces, and data management; a system of tools for the materials domain expert involved in design. Engineering design solutions initially build from generalisations. POISE represents multiple levels of generalisations from classifications of polymer information. The class-instance paradigm classifies software objects. An object’s behaviour is an exclusive function of its class. Polymer’s behaviours are a function of multiple orthogonal factors, like chemistry and processing, therefore multiple orthogonal classes must represent polymers. Taxonomy only represents one of these factors. The Enhancer mechanism resolves this conflict between classification and representation. Polymer classification is not well established, with new materials evolving. The software compensates by evolving the classification schema. Guided with a specialised interface tool, the domain expert updates the schema by adding new polymer families and re-classifying existing classes. Through analysing the generalisations in the classification, the domain expert can develop an appropriate classification. This analysis relies on the engineering properties differentiating the principal material qualities. Standard properties do not distinguish specific structural differences in polymer materials, necessitating new properties. Material properties distinguish materials in the domain whereas the classes describe the properties of polymer objects. Domain experts add new properties to the polymer classes to distinguish polymer objects. Properties are independent objects that partially describe the class template; Partial Template Objects. Persistence of personal design information and management of shared data requires dichotomous database management. Shared data requires multi-user access, and consequently transaction management. Transaction management in object-oriented systems often holds resources for a long duration. Transaction declaration hinders transparent access to storage, and corrupts the representation. For single-user design information, transactions are implicit with access. Database proxies provide transparent per-object transaction management to persistent design information. The WorkBase is an object-storage utility that utilises Enhancers as proxies

Grand tour of concepts for object-orientation from a database point of view

Over the last few years, object-orientation has gained more and more importance within several disciplines of computer science (e.g. programming languages, knowledge engineering, and database systems). Numerous papers have defined one or another of its underlying concepts (sometimes in quite different ways), and some systems have been developed following those heterogeneous definitions. Nevertheless, papers investigating the dependencies and degrees of freedom of these concepts are rarely found. For this reason, the goal of this paper is not to add yet another definition of object-oriented concepts, but to identify existing relationships among these basic concepts that allow one to cover and classify various conceivable combinations of these conceptual building blocks. Dependencies, orthogonalities, and relations among concepts like object identity, encapsulation, classification, generalization, inheritance, etc. are revealed, showing numerous ways to compose different shades of object-orientation. This leads to alternatives encountered when constructing object-oriented systems, which are illustrated by classifying some well-known systems and prototypes from different areas. However, it is not our purpose to analyze the relative importance of these concepts. Instead, we investigate the concepts from a neutral point of view, presenting (but not evaluating) several degrees of object-orientation

Towards a Canonical Method to Solve Patterns of Ontology Modeling Issues (9 Month Report)

This report presents a brief description of the different activities carried out in the field of ontology engineering. It identifies a lack of guidelines on how to address modeling issues during the ontology conceptualization phase, in the current methodologies to build ontologies from scratch. It describes an example scenario of an ontology modeling task and it proposes a possible solution inspired by folksonomy based systems and faceted classification. This is followed by a study of the difficulties found to adapt the IEEE Learning Object Metadata (LOM) standard to model an ontology fit for purpose in a specific university curricula domain. It also gives an example of a prototype for a potential next generation semantic web application and a brief summary of the main viewpoints that will characterize such applications. Finally it outlines possible paths of further research to address ontology modeling issues and it suggests looking at various sources for possible solutions (schemes of folksonomy and faceted classification, design principles of object-oriented and relational database applications, and ontology evaluation)

Information Retrieval: A Comparative Study of Textual Indexing using an Oriented Object Database (DB4O) and the Inverted File

The Growth in the volume of text data such as books and articles in libraries for centuries has imposed to establish effective mechanisms to locate them. Early techniques such as abstraction, indexing and the use of classification categories have marked the birth of a new field of research called "Information Retrieval". Information Retrieval (IR) can be defined as the task of defining models and systems whose purpose is to facilitate access to a set of documents in electronic form (corpus) to allow a user to find the relevant ones for him, that is to say, the contents which matches with the information needs of the user. Most of the models of information retrieval use a specific data structure to index a corpus which is called "inverted file" or "reverse index". This inverted file collects information on all terms over the corpus documents specifying the identifiers of documents that contain the term in question, the frequency of each term in the documents of the corpus, the positions of the occurrences of the word. In this paper we use an oriented object database (db4o) instead of the inverted file, that is to say, instead to search a term in the inverted file, we will search it in the db4o database. The purpose of this work is to make a comparative study to see if the oriented object databases may be competing for the inverse index in terms of access speed and resource consumption using a large volume of data

A Collection Model for Data Management in Object-Oriented Systems

This thesis addresses the question of how to provide data management services in object-oriented systems with reliable persistent object stores. It proposes an object data model, called the collection model, which serves as a foundation for the construction of such services. The collection model is general in that it is independent of any particular implementation platform. In part, this independence is achieved through the separation of the data model from the underlying type model. There are two components of the collection model - a structural model, BROOM, and an operational model based on an algebra of collections. The structural model is semantically rich and exhibits properties of both the entity-relationship and semantic data models. Hoary collections are used to represent entity categories and binary collections to represent relationships between entities. Classification structures are based on the notion of a. collection family which represents various forms of conceptual dependencies among the collections of a. family. The requirements for supporting the various forms of evolution in object-oriented database systems are presented. An extension to the collection model is proposed to support object evolution whereby objects can migrate within classification structures. Two existing realisations of the collection model are described. One is a. prototype, single-user system implemented in Prolog. The other forms the basis of the Object Data. Management Services of the Comandos platform for distributed, object-oriented applications. A general approach to object data model design, specification and realisation is advocated. In particular, a metacircular description of the collection model is used as an intermediate form of data model specification. This metacircular description is then transformed into a formal specification in the Z language