299 research outputs found

    Formal design of data warehouse and OLAP systems : a dissertation presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Information Systems at Massey University, Palmerston North, New Zealand

    Get PDF
    A data warehouse is a single data store, where data from multiple data sources is integrated for online business analytical processing (OLAP) of an entire organisation. The rationale being single and integrated is to ensure a consistent view of the organisational business performance independent from different angels of business perspectives. Due to its wide coverage of subjects, data warehouse design is a highly complex, lengthy and error-prone process. Furthermore, the business analytical tasks change over time, which results in changes in the requirements for the OLAP systems. Thus, data warehouse and OLAP systems are rather dynamic and the design process is continuous. In this thesis, we propose a method that is integrated, formal and application-tailored to overcome the complexity problem, deal with the system dynamics, improve the quality of the system and the chance of success. Our method comprises three important parts: the general ASMs method with types, the application tailored design framework for data warehouse and OLAP, and the schema integration method with a set of provably correct refinement rules. By using the ASM method, we are able to model both data and operations in a uniform conceptual framework, which enables us to design an integrated approach for data warehouse and OLAP design. The freedom given by the ASM method allows us to model the system at an abstract level that is easy to understand for both users and designers. More specifically, the language allows us to use the terms from the user domain not biased by the terms used in computer systems. The pseudo-code like transition rules, which gives the simplest form of operational semantics in ASMs, give the closeness to programming languages for designers to understand. Furthermore, these rules are rooted in mathematics to assist in improving the quality of the system design. By extending the ASMs with types, the modelling language is tailored for data warehouse with the terms that are well developed for data-intensive applications, which makes it easy to model the schema evolution as refinements in the dynamic data warehouse design. By providing the application-tailored design framework, we break down the design complexity by business processes (also called subjects in data warehousing) and design concerns. By designing the data warehouse by subjects, our method resembles Kimball's "bottom-up" approach. However, with the schema integration method, our method resolves the stovepipe issue of the approach. By building up a data warehouse iteratively in an integrated framework, our method not only results in an integrated data warehouse, but also resolves the issues of complexity and delayed ROI (Return On Investment) in Inmon's "top-down" approach. By dealing with the user change requests in the same way as new subjects, and modelling data and operations explicitly in a three-tier architecture, namely the data sources, the data warehouse and the OLAP (online Analytical Processing), our method facilitates dynamic design with system integrity. By introducing a notion of refinement specific to schema evolution, namely schema refinement, for capturing the notion of schema dominance in schema integration, we are able to build a set of correctness-proven refinement rules. By providing the set of refinement rules, we simplify the designers's work in correctness design verification. Nevertheless, we do not aim for a complete set due to the fact that there are many different ways for schema integration, and neither a prescribed way of integration to allow designer favored design. Furthermore, given its °exibility in the process, our method can be extended for new emerging design issues easily

    Design of Industrial Floors: Principles for Control of Warping.

    Get PDF
    The Slab-on-grade, which include Industrial floors, can be defined, according to ACI Committee 360,1 as a slab continuously supported by ground with an area of more than twice the area required to support the imposed loads. The slab may be plain or reinforced and may include stiffening elements such as ribs and hidden beams. The reinforcement may be provided for structural purpose or for the control of effects of shrinkage and temperature changes. Floar slabs are very important elements ofindustrial facilities. The slab must be uniformly flat and joints must be relatively level without excessive movements to allow manufacturing equipment and fork trucks to perform properly

    Ontology based data warehousing for mining of heterogeneous and multidimensional data sources

    Get PDF
    Heterogeneous and multidimensional big-data sources are virtually prevalent in all business environments. System and data analysts are unable to fast-track and access big-data sources. A robust and versatile data warehousing system is developed, integrating domain ontologies from multidimensional data sources. For example, petroleum digital ecosystems and digital oil field solutions, derived from big-data petroleum (information) systems, are in increasing demand in multibillion dollar resource businesses worldwide. This work is recognized by Industrial Electronic Society of IEEE and appeared in more than 50 international conference proceedings and journals

    Collision avoidance and dynamic modeling for wheeled mobile robots and industrial manipulators

    Get PDF
    Collision Avoidance and Dynamic Modeling are key topics for researchers dealing with mobile and industrial robotics. A wide variety of algorithms, approaches and methodologies have been exploited, designed or adapted to tackle the problems of finding safe trajectories for mobile robots and industrial manipulators, and of calculating reliable dynamics models able to capture expected and possible also unexpected behaviors of robots. The knowledge of these two aspects and their potential is important to ensure the efficient and correct functioning of Industry 4.0 plants such as automated warehouses, autonomous surveillance systems and assembly lines. Collision avoidance is a crucial aspect to improve automation and safety, and to solve the problem of planning collision-free trajectories in systems composed of multiple autonomous agents such as unmanned mobile robots and manipulators with several degrees of freedom. A rigorous and accurate model explaining the dynamics of robots, is necessary to tackle tasks such as simulation, torque estimation, reduction of mechanical vibrations and design of control law

    Systematic parameter analysis for selective laser melting (SLM) of silver-based materials.

    Get PDF
    Selective Laser Melting (SLM) is a growing technology for the additive manufacturing of parts and structures. Based on a powder layer technique, a laser locally melts the powder and forms new structures. [1] In this approach, silver-based alloy powders will be used. The processing of this kind of material is considered difficult compared to other powder materials such as mild steels or tool steels. Silver powder is a highly reflecting material and has excellent thermal conductivity. Both properties make it difficult to process using Selective Laser Melting. Due to its high price, industries use silver parts as economically as possible so that the parts tend to be thin and light weight. Therefore, one limiting constraint should be the manufacturing of thin, hollow parts. The second constraint is the usage of a laser with small power output. The reasons why this machine will be used is that it is affordable for a large amount of companies, that it can be placed nearly everywhere and that it economically beats large workshops with cast and milling facilities. Since AgCu7 is a typical artwork material and AgCu28 is a typical technical material, this work is related to further research on the processing of both materials. Processing maps were developed using the response surface method. The dissertation covers the questions why silver is used, what was done, which methods are available to answer upcoming questions and which solutions are proposed. Chapter one provides an introduction to the topic. Chapter two covers information that is available about different precious materials, physical relations and other aspects that are necessary to understand what happens in the melt pool. Chapter three deals with important parameters and collects some fundamental approaches to uncover new relations. Chapter four shows the pretests, powder distributions, absorptivity measurements, and necessary steps to manufacture hollow structures. In chapter five, six, and seven the experiments for AgCu7 and AgCu28 are described. Factorial designs and the response surface method were used in order to analyze the dependency of process parameters on porosity. In chapter eight, the results of the materials are compared. Chapter nine presents the summary and future perspectives

    Efficient Decision Support Systems

    Get PDF
    This series is directed to diverse managerial professionals who are leading the transformation of individual domains by using expert information and domain knowledge to drive decision support systems (DSSs). The series offers a broad range of subjects addressed in specific areas such as health care, business management, banking, agriculture, environmental improvement, natural resource and spatial management, aviation administration, and hybrid applications of information technology aimed to interdisciplinary issues. This book series is composed of three volumes: Volume 1 consists of general concepts and methodology of DSSs; Volume 2 consists of applications of DSSs in the biomedical domain; Volume 3 consists of hybrid applications of DSSs in multidisciplinary domains. The book is shaped upon decision support strategies in the new infrastructure that assists the readers in full use of the creative technology to manipulate input data and to transform information into useful decisions for decision makers

    Advances in Design by Metallic Materials: Synthesis, Characterization, Simulation and Applications

    Get PDF
    Very recently, a great deal of attention has been paid by researchers and technologists to trying to eliminate metal materials in the design of products and processes in favor of plastics and composites. After a few years, it is possible to state that metal materials are even more present in our lives and this is especially thanks to their ability to evolve. This Special Issue is focused on the recent evolution of metals and alloys with the scope of presenting the state of the art of solutions where metallic materials have become established, without a doubt, as a successful design solution thanks to their unique properties
    • …
    corecore