Object reational data base management systems and applications in document retrieval

http://deepblue.lib.umich.edu/bitstream/2027.42/96902/1/MBA_JayaramanaF_1996Final.pd

Integrated information model for managing the product introduction process

The thesis proposes an integrated product introduction (PI) information model for managing the product introduction process in an efficient manner. Through the process of product introduction, ideas and needs are converted to the information from which technical systems and products can be made and sold. Two critical factors for its success are the management of the product introduction activities, and the quality and functionality of its output (i.e. the product) which itself depends on the quality of the PI process. The process is as effective as the decisions made within it, and as efficient as the speed with which the information required for each decision is made available. In order to improve the efficiency of the management of the project in meeting its diverse targets (project time, project cost, product cost and uparrow product functionality), a model that integrates the targets would be essential in relating the activities of the project to their outcomes. Existing information models in related areas such as design, product development, project management, computer aided design and manufacturing consider some of these targets, but not all of them simultaneously. Especially product functionality is not considered along with the other targets of the PI project. The project introduction information includes managerial and technical information and complex associations among these two categories. Its representation places a challenging and novel set of demands on database technology as it is evolving, distributed and heterogeneous. Existing information models do not address the link between the managerial and technical information, and their continual evolution. Based on a detailed analysis of its nature and content, the thesis presents a three dimensional model of the product introduction information from three related but different viewpoints:- (1) entity-relationship or objects, (2) intra-layer integration and (3) evolution, each capturing important aspects of the PI information, but all required for a complete description. The overall three dimensional information model includes the following layers:- from view 1 - product functionality, process or project, product introduction resources, product and information map; from view 2 - node, relationship, and organisation; from view 3 - meta-model, data model, and data. Each model describes one aspect of the product introduction information but contains references to the others. The building blocks of the information model are described using schema definitions

Query processing in temporal object-oriented databases

This PhD thesis is concerned with historical data management in the context of objectoriented databases. An extensible approach has been explored to processing temporal object queries within a uniform query framework. By the uniform framework, we mean temporal queries can be processed within the existing object-oriented framework that is extended from relational framework, by extending the existing query processing techniques and strategies developed for OODBs and RDBs. The unified model of OODBs and RDBs in UmSQL/X has been adopted as a basis for this purpose. A temporal object data model is thereby defined by incorporating a time dimension into this unified model of OODBs and RDBs to form temporal relational-like cubes but with the addition of aggregation and inheritance hierarchies. A query algebra, that accesses objects through these associations of aggregation, inheritance and timereference, is then defined as a general query model /language. Due to the extensive features of our data model and reducibility of the algebra, a layered structure of query processor is presented that provides a uniforrn framework for processing temporal object queries. Within the uniform framework, query transformation is carried out based on a set of transformation rules identified that includes the known relational and object rules plus those pertaining to the time dimension. To evaluate a temporal query involving a path with timereference, a strategy of decomposition is proposed. That is, evaluation of an enhanced path, which is defined to extend a path with time-reference, is decomposed by initially dividing the path into two sub-paths: one containing the time-stamped class that can be optimized by making use of the ordering information of temporal data and another an ordinary sub-path (without time-stamped classes) which can be further decomposed and evaluated using different algorithms. The intermediate results of traversing the two sub-paths are then joined together to create the query output. Algorithms for processing the decomposed query components, i. e., time-related operation algorithms, four join algorithms (nested-loop forward join, sort-merge forward join, nested-loop reverse join and sort-merge reverse join) and their modifications, have been presented with cost analysis and implemented with stream processing techniques using C++. Simulation results are also provided. Both cost analysis and simulation show the effects of time on the query processing algorithms: the join time cost is linearly increased with the expansion in the number of time-epochs (time-dimension in the case of a regular TS). It is also shown that using heuristics that make use of time information can lead to a significant time cost saving. Query processing with incomplete temporal data has also been discussed

A Systematic Performance Study of Object Database Management Systems

Many previous performance benchmarks for Object Database Management Systems (ODBMSs) have typically used arbitrary sets of tests based on what their designers felt were the characteristics of Engineering applications. Increasingly, however, ODBMSs are being used in non-engineering domains, such as Financial Trading, Clinical Healthcare, Telecommunications Network Management, etc. Part of the reason for this is that the technology has matured over the past few years and has become a less risky choice for organisations looking for better w'ays to manage complex data. However, the development of suitable application- or industry-specific benchmarks, based on actual performance studies, has not paralleled this growth. The research reported here approaches performance evaluation of ODBMSs pragmatically. It uses a combination of case studies and benchmark experiments to investigate the performance characteristics of ODBMSs for particular applications, following the successful use of this approach by Youssef [Youss93] for studying the performance of On- Line Transaction Processing (OLTP) applications for Relational Database Management Systems (RDBMSs). Six case studies at five organisations show’ that organisations consider a wide range of factors when undertaking their own performance studies or benchmarks. Furthermore, none of the studied organisations considered using any public benchmarks. Six current and derived benchmarks also highlight statistically significant performance differences between three major commercial products: Objectivity/DB, ObjectStore and UniSQL. These benchmarks indicate the suitability of the products tested for particular application domains. The research could not find any evidence at this time to support the concept of a generic or canonical performance workload for ODBMSs. This is demonstrated by the case studies and supported by the benchmark experiments. However, the research shows that performance benchmarks serve a very useful role in ODBMS evaluations and can help identify architectural and quality problems with products that would not otherwise be observed until significant application or system development was already in progress

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

Aviation System Analysis Capability Executive Assistant Design

In this technical document, we describe the design developed for the Aviation System Analysis Capability (ASAC) Executive Assistant (EA) Proof of Concept (POC). We describe the genesis and role of the ASAC system, discuss the objectives of the ASAC system and provide an overview of components and models within the ASAC system, and describe the design process and the results of the ASAC EA POC system design. We also describe the evaluation process and results for applicable COTS software. The document has six chapters, a bibliography, three appendices and one attachment

Integrated software architecture to support modern experimental biology

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004.Includes bibliographical references (p. 127-132).Over the past several years, the explosive growth of biological data generated by new high-throughput instruments has virtually begun to drown the biological community. There is no established infrastructure to deal with these data in a consistent and successful fashion. This thesis presents a new informatics platform capable of supporting a large subsection of the experimental methods found in modem biology. A consistent data definition strategy is outlined that can handle gel electrophoresis, microarray, fluorescence activated cell sorting, mass spectrometry, and microscopy within a single coherent set of information object definitions. A key issue for interoperability is that common attributes are made truly identical between the different methods. This dramatically decreases the overhead of separate and distinct classes for each method, and reserves the uniqueness for attributes that are different between the methods. Thus, at least one higher level of integration is obtained. The thesis shows that rich object-oriented modeling together with object-relational database features and the uniform treatment of data and metadata is an ideal candidate for complex experimental information integration tasks. This claim is substantiated by elaborating on the coherent set of information object definitions and testing the corresponded database using real experimental data. A first implementation of this work--ExperiBase--is an integrated software platform to store and query data generated by the leading experimental protocols used in biology within a single database. It provides: comprehensive database features for searching and classifying; web-based client interfaces; web services; data import and export capabilities to accommodate other data(cont.) repositories; and direct support for metadata produced by analysis programs. Using JDBC, Java Servlets and Java Server Pages, SOAP, XML, and IIOP/CORBA's technologies, the information architecture is portable and platform independent. The thesis develops an ExperiBase XML according to the single coherent set of information object definitions, and also presents a new way of database federation--translating heterogeneous database schemas into the common ExperiBase XML schema and then merging the output: XML messages to get data federated. ExperiBase has become a reference implementation of the I3C Life Science Object Ontologies group.by Shixin Zhang.Ph.D

Prefetching techniques for client server object-oriented database systems

The performance of many object-oriented database applications suffers from the page fetch latency which is determined by the expense of disk access. In this work we suggest several prefetching techniques to avoid, or at least to reduce, page fetch latency. In practice no prediction technique is perfect and no prefetching technique can entirely eliminate delay due to page fetch latency. Therefore we are interested in the trade-off between the level of accuracy required for obtaining good results in terms of elapsed time reduction and the processing overhead needed to achieve this level of accuracy. If prefetching accuracy is high then the total elapsed time of an application can be reduced significantly otherwise if the prefetching accuracy is low, many incorrect pages are prefetched and the extra load on the client, network, server and disks decreases the whole system performance. Access pattern of object-oriented databases are often complex and usually hard to predict accurately. The ..