The Semantic Web in Federated Information Systems: A Space Physics Case Study

This paper presents a new theoretical contribution that provides a middle-of-the-road approach to formal ontologies in federated information systems. NASA’s space physics domain, like many other domains, is relatively unfamiliar with the emerging Semantic Web. This work offers a new framework that garners the benefits of formal logic yet shields participants and users from the details of the technology. Moreover, the results of a case study involving the utilization of the Semantic Web within NASA’s space physics domain are presented. A real-world search and retrieval system, relying on relational database technology, is compared against a near identical system that incorporates a formal ontology. The efficiency, efficacy, and implementation details of the Semantic Web are compared against the established relational database technology

Integration ontology for distributed database

In this work we will study the problem of the design of the "Integration Model for Distributed Database System". We particularly design the canonical model through the ontological handling of the information. The ontology is designed in a way that allows the description of a database like a set of representative terms of its different components. In this ontology, the definitions use classes, relations, functions, among other things, of databases, to describe their components, operations and restrictions, as well as, the process of integration. These databases can be Relational, Fuzzy, Intelligent and Multimedia1st International Workshop on Advanced Software Engineering: Expanding the Frontiers of Software Technology - Session 2: Software ModelingRed de Universidades con Carreras en Informática (RedUNCI

Integration ontology for distributed database

In this work we will study the problem of the design of the "Integration Model for Distributed Database System". We particularly design the canonical model through the ontological handling of the information. The ontology is designed in a way that allows the description of a database like a set of representative terms of its different components. In this ontology, the definitions use classes, relations, functions, among other things, of databases, to describe their components, operations and restrictions, as well as, the process of integration. These databases can be Relational, Fuzzy, Intelligent and Multimedia1st International Workshop on Advanced Software Engineering: Expanding the Frontiers of Software Technology - Session 2: Software ModelingRed de Universidades con Carreras en Informática (RedUNCI

INTRODUCTION OF CENTRAL USER MANAGEMENT IN A LARGE UNIVERSITY HOSPITAL - A CASE STUDY

The department “organization and information technology” (OIT) of the Faculty of Medicine of the “Ludwig-Maximilians-Universität München” introduced a system to centrally manage user accounts and security during the last two years. The initial state was that we had several user directories for different services, resulting in high operating expense. We describe the aims, the concepts, the techniques, the realization and the difficulties we had introducing a central user directory. The new central user directory covers not only authentication, but also authorization in the connected subsystems. The following subsystems are connected: Windows logon, Email and Calendaring, various intranet services like medical documentation system, diagnostic findings of clinical chemistry or radiology, remote access to Email and Calendaring via a firewall, RADIUS and last but not least logging on to SAP, which is our ERP (enterprise resource planning system)

System level airborne avionics prognostics for maintenance, repair and overhaul

The aim of this study is to propose an alternative approach in prognostics for airborne avionics system in order to enhance maintenance process and aircraft availability. The objectives are to analyse the dependency of avionic systems for fault propagation behaviour degradation, research and develop methods to predict the remaining useful life of avionics Line Replaceable Units (LRU), research and develop methods to evaluate and predict the degradation performances of avionic systems, and lastly to develop software simulation systems to evaluate methods developed. One of the many stakeholders in the aircraft lifecycle includes the Maintenance, Repair and Overhaul (MRO) industry. The predictable logistics process to some degree as an outcome of IVHM gives benefit to the MRO industry. In this thesis, a new integrated numerical methodology called ‘System Level Airborne Avionic Prognostics’ or SLAAP is developed; looking at a top level solution in prognostics. Overall, this research consists of two main elements. One is to thoroughly understand and analyse data that could be utilised. Secondly, is to apply the developed methodology using the enhanced prognostic methodology. Readily available fault tree data is used to analyse the dependencies of each component within the LRUs, and performance were simulated using the linear Markov Model to estimate the time to failure. A hybrid approach prognostics model is then integrated with the prognostics measures that include environmental factors that contribute to the failure of a system, such as temperature. This research attempts to use data that is closest to the data available in the maintenance repair and overhaul industry. Based on a case study on Enhanced Ground Proximity Warning System (EGPWS), the prognostics methodology developed showed a sufficiently close approximation to the Mean Time Before Failure (MTBF) data supplied by the Original Equipment Manufacturer (OEM). This validation gives confidence that the proposed methodology will achieve its objectives and it should be further developed for use in the systems design process

An object query language for multimedia federations

The Fischlar system provides a large centralised repository of multimedia files. As expansion is difficult in centralised systems and as different user groups have a requirement to define their own schemas, the EGTV (Efficient Global Transactions for Video) project was established to examine how the distribution of this database could be managed. The federated database approach is advocated where global schema is designed in a top-down approach, while all multimedia and textual data is stored in object-oriented (O-O) and object-relational (0-R) compliant databases. This thesis investigates queries and updates on large multimedia collections organised in the database federation. The goal of this research is to provide a generic query language capable of interrogating global and local multimedia database schemas. Therefore, a new query language EQL is defined to facilitate the querying of object-oriented and objectrelational database schemas in a database and platform independent manner, and acts as a canonical language for database federations. A new canonical language was required as the existing query language standards (SQL: 1999 and OQL) axe generally incompatible and translation between them is not trivial. EQL is supported with a formally defined object algebra and specified semantics for query evaluation. The ability to capture and store metadata of multiple database schemas is essential when constructing and querying a federated schema. Therefore we also present a new platform independent metamodel for specifying multimedia schemas stored in both object-oriented and object-relational databases. This metadata information is later used for the construction of a global schemas, and during the evaluation of local and global queries. Another important feature of any federated system is the ability to unambiguously define database schemas. The schema definition language for an EGTV database federation must be capable of specifying both object-oriented and object-relational schemas in the database independent format. As XML represents a standard for encoding and distributing data across various platforms, a language based upon XML has been developed as a part of our research. The ODLx (Object Definition Language XML) language specifies a set of XMLbased structures for defining complex database schemas capable of representing different multimedia types. The language is fully integrated with the EGTV metamodel through which ODLx schemas can be mapped to 0-0 and 0-R databases

System level airborne avionics prognostics for maintenance, repair and overhaul

The aim of this study is to propose an alternative approach in prognostics for airborne avionics system in order to enhance maintenance process and aircraft availability. The objectives are to analyse the dependency of avionic systems for fault propagation behaviour degradation, research and develop methods to predict the remaining useful life of avionics Line Replaceable Units (LRU), research and develop methods to evaluate and predict the degradation performances of avionic systems, and lastly to develop software simulation systems to evaluate methods developed. One of the many stakeholders in the aircraft lifecycle includes the Maintenance, Repair and Overhaul (MRO) industry. The predictable logistics process to some degree as an outcome of IVHM gives benefit to the MRO industry. In this thesis, a new integrated numerical methodology called ‘System Level Airborne Avionic Prognostics’ or SLAAP is developed; looking at a top level solution in prognostics. Overall, this research consists of two main elements. One is to thoroughly understand and analyse data that could be utilised. Secondly, is to apply the developed methodology using the enhanced prognostic methodology. Readily available fault tree data is used to analyse the dependencies of each component within the LRUs, and performance were simulated using the linear Markov Model to estimate the time to failure. A hybrid approach prognostics model is then integrated with the prognostics measures that include environmental factors that contribute to the failure of a system, such as temperature. This research attempts to use data that is closest to the data available in the maintenance repair and overhaul industry. Based on a case study on Enhanced Ground Proximity Warning System (EGPWS), the prognostics methodology developed showed a sufficiently close approximation to the Mean Time Before Failure (MTBF) data supplied by the Original Equipment Manufacturer (OEM). This validation gives confidence that the proposed methodology will achieve its objectives and it should be further developed for use in the systems design process

The mediated data integration (MeDInt) : An approach to the integration of database and legacy systems

The information required for decision making by executives in organizations is normally scattered across disparate data sources including databases and legacy systems. To gain a competitive advantage, it is extremely important for executives to be able to obtain one unique view of information in an accurate and timely manner. To do this, it is necessary to interoperate multiple data sources, which differ structurally and semantically. Particular problems occur when applying traditional integration approaches, for example, the global schema needs to be recreated when the component schema has been modified. This research investigates the following heterogeneities between heterogeneous data sources: Data Model Heterogeneities, Schematic Heterogeneities and Semantic Heterogeneities. The problems of existing integration approaches are reviewed and solved by introducing and designing a new integration approach to logically interoperate heterogeneous data sources and to resolve three previously classified heterogeneities. The research attempts to reduce the complexity of the integration process by maximising the degree of automation. Mediation and wrapping techniques are employed in this research. The Mediated Data Integration (MeDint) architecture has been introduced to integrate heterogeneous data sources. Three major elements, the MeDint Mediator, wrappers, and the Mediated Data Model (MDM) play important roles in the integration of heterogeneous data sources. The MeDint Mediator acts as an intermediate layer transforming queries to sub-queries, resolving conflicts, and consolidating conflict-resolved results. Wrappers serve as translators between the MeDint Mediator and data sources. Both the mediator and wrappers arc well-supported by MDM, a semantically-rich data model which can describe or represent heterogeneous data schematically and semantically. Some organisational information systems have been tested and evaluated using the MeDint architecture. The results have addressed all the research questions regarding the interoperability of heterogeneous data sources. In addition, the results also confirm that the Me Dint architecture is able to provide integration that is transparent to users and that the schema evolution does not affect the integration