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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

A Study of Partitioning and Parallel UDF Execution with the SAP HANA Database

Große, Philipp, May, Norman, Lehner, Wolfgang 08 July 2014 (has links) (PDF)
Large-scale data analysis relies on custom code both for preparing the data for analysis as well as for the core analysis algorithms. The map-reduce framework offers a simple model to parallelize custom code, but it does not integrate well with relational databases. Likewise, the literature on optimizing queries in relational databases has largely ignored user-defined functions (UDFs). In this paper, we discuss annotations for user-defined functions that facilitate optimizations that both consider relational operators and UDFs. We believe this to be the superior approach compared to just linking map-reduce evaluation to a relational database because it enables a broader range of optimizations. In this paper we focus on optimizations that enable the parallel execution of relational operators and UDFs for a number of typical patterns. A study on real-world data investigates the opportunities for parallelization of complex data flows containing both relational operators and UDFs.
12

Creating Markup : Exploring the concept of users defining syntax

Van den Weghe, Matthias January 2016 (has links)
A variety of markup languages exist for formatting text and exporting to HTML. These languages are tailored to the needs in a specific context by specialising tags, selecting tags and limiting the number of possible distinctions to a subset of what is available in HTML. However, limiting the number of possible distinctions creates problems when changes occur in the context. The real world is ever-changing, thus that which models it must be able to reflect the changes in the operational environment to remain relevant and satisfactory. Incorporating new requirements and adjusting to the changes in requirements means adapting and evolving. This thesis explores giving document authors the possibility to extend and modify the repertoire of available markup tags when new user requirements demand it. What is presented is a prototype which allows the user to tailor the markup and also adapt it to changes in the environment. The system allows users to create their own set of markup tags, annotate their documents with them, and export a generated XML document. Users create the tag and assign a meaning to it, when changes occur in the requirements they can be implemented by modifying the tags, extending the repertoire by adding tags, or changing the meaning of a defined tag.
13

An ABAQUS Implementation of the Cell-based Smoothed Finite Element Method Using Quadrilateral Elements

Wang, Sili January 2014 (has links)
No description available.
14

Finite Deformations of Fiber-Reinforced Rubberlike Solids, and of Adhesively Bonded T-peel Joints

Li, Qian 25 April 2018 (has links)
Fiber-reinforced rubberlike materials (FRRM) commonly used in tires undergo large deformations, and exhibit different response in tension and compression along the fiber direction. Assuming that the response of a fiber-reinforced rubberlike material can be modeled as transversely isotropic with the fiber direction as the axis of transverse isotropy, we express the stored energy function, W, in terms of the five invariants of the right Cauchy-Green strain tensor and the fiber direction, and account for different response in tension and compression along the fiber direction. It has been shown in the literature that in shear-dominated deformations, the 5th invariant, I5, significantly contribution to the stress-strain curve. We have implemented the constitutive relation in the commercial software, LS-DYNA. The numerical solutions of several boundary value problems studied here agree with their analytical solutions derived by using Ericksen's inverse approach, in which a part of the solution is assumed and unknowns in the presumed solution are then found by analyzing the pertinent boundary value problem. However, computed results have not been compared with experimental findings. For W of the FRRMs an expression that is a complete quadratic function of the five invariants is also examined. Homogeneous deformations such as simple extension, simple shear, and biaxial loading problems are studied to delineate the mechanical behaviors of FRRMs. Consistency with the infinitesimal deformation theory requires that linear terms in the 4th and 5th invariants, I4 and I5, be included in the expression for W. Stability analysis of deformations reveals the qualitative changes triggered by the second order terms of the quadratic function. Analytical solutions for inflation, extension and twist deformations caused by internal pressure, end torque, and axial force for a pressurized cylindrical laminate are derived using Ericksen's inverse method. Effects of fiber orientations on the mechanical behaviors of a +/-α angle-ply cylindrical tube are investigated using the derived analytical solutions. The T-peel test, widely used for characterizing adhesion across a plethora of adhesives, adherends, and geometries, results in a range of responses that may complicate meaningful interpretation of the test data. This research effort, involving several specific specimen types, was undertaken to investigate concerns that commonly used configurations may not always result in plateaus in the force-displacement response. We experimentally and numerically study debonding of T-peel specimens having 75 mm bond length and 0.81 mm thick adherends made of either 6061 aluminum (Al) or one of the three steels (G70 70U hot dip galvanized, E60 elctrogalvanized (EGZ), 1010 cold-rolled steel (CRS) bonded with either LORD® 406 or Maxlok™ acrylic adhesive. For the EGZ and the Al adherends, specimens with a bond length of 250 mm and adherend thickness of 1.60 mm are also examined. Effects of adherend materials and thicknesses, bond lengths, and adhesives on test results are examined using three metrics to interpret the T-peel bond performance. We find a limited correlation between the commonly used "T-peel strength" and the energy dissipated per unit debond area. For those two metrics, the relative performances of the CRS and the Al specimens are quite different. Quasi-static plane strain deformations of the test specimens are analyzed by the finite element method (FEM) and a cohesive zone model using the commercial software, ABAQUS, to help interpret the test data. Numerical results provided energies required to elastically and plastically deform the adherends, and help determine the transition from non-self-similar to self-similar debonding. The FE simulations also facilitate determination of the fraction of the crosshead displacement at which self-similar debonding occurs. Results reported herein should help practitioners select appropriate specimen dimensions for extracting meaningful data for adhesive performance. / Ph. D.
15

A Methodology for Domain-Specific Conceptual Data Modeling and Querying

Tian, Hao 02 May 2007 (has links)
Traditional data management technologies originating from business domain are currently facing many challenges from other domains such as scientific research. Data structures in databases are becoming more and more complex and data query functions are moving from the back-end database level towards the front-end user-interface level. Traditional query languages such as SQL, OQL, and form-based query interfaces cannot fully meet the needs today. This research is motivated by the data management issues in life science applications. I propose a methodology for domain-specific conceptual data modeling and querying. The methodology can be applied to any domain to capture more domain semantics and empower end-users to formulate a query at the conceptual level with terminologies and functions familiar to them. The query system resulting from the methodology is designed to work on all major types of database management systems (DBMS) and support end-users to dynamically define and add new domain-specific functions. That is, all user-defined functions can be either pre-defined by domain experts and/or data model creators at the time of system creation, or dynamically defined by end-users from the client side at any time. The methodology has a domain-specific conceptual data model (DSC-DM) and a domain-specific conceptual query language (DSC-QL). DSC-QL uses only the abstract concepts, relationships, and functions defined in DSC-DM. It is a user-oriented high level query language and intentionally designed to be flexible, extensible, and readily usable. DSC-QL queries are much simpler than corresponding SQL or OQL queries because of advanced features such as user-defined functions, composite and set attributes, dot-path expressions, and super-classes. DSC-QL can be translated into SQL and OQL through a dynamic mapping function, and automatically updated when the underlying database schema evolves. The operational and declarative semantics of DSC-QL are formally defined in terms of graphs. A normal form for DSC-QL as a standard format for the mappings from flexible conceptual expressions to restricted SQL or OQL statements is also defined. Two translation algorithms from normalized DSC-QL to SQL and OQL are introduced. Through comparison, DSC-QL is shown to have very good balance between simplicity and expressive power and is suitable for end-users. Implementation details of the query system are reported as well. Two prototypes have been built. One prototype is for neuroscience domain, which is built on an object-oriented DBMS. The other one is for traditional business domain, which is built on a relational DBMS.
16

Návrh databáze pro připojení systému SAP jako zdroje dat pro webovou aplikaci / Database design for connecting SAP as a data source for a Web application

MARHOUN, Lukáš January 2016 (has links)
The thesis deals with connecting SAP ERP system via local database system MS SQL Server using the tools SAP BI, data synchronization between systems and advanced usage of T-SQL language for preparing data for web applications and reports written in PHP. The thesis contains a brief overview of the SAP system and the possibility of connecting to the SAP system. The general principles of described solution can be used in conjunction with other systems and programming languages.
17

A Study of Partitioning and Parallel UDF Execution with the SAP HANA Database

Große, Philipp, May, Norman, Lehner, Wolfgang 08 July 2014 (has links)
Large-scale data analysis relies on custom code both for preparing the data for analysis as well as for the core analysis algorithms. The map-reduce framework offers a simple model to parallelize custom code, but it does not integrate well with relational databases. Likewise, the literature on optimizing queries in relational databases has largely ignored user-defined functions (UDFs). In this paper, we discuss annotations for user-defined functions that facilitate optimizations that both consider relational operators and UDFs. We believe this to be the superior approach compared to just linking map-reduce evaluation to a relational database because it enables a broader range of optimizations. In this paper we focus on optimizations that enable the parallel execution of relational operators and UDFs for a number of typical patterns. A study on real-world data investigates the opportunities for parallelization of complex data flows containing both relational operators and UDFs.
18

Development of a 3D Computational Vocal Fold Model Optimization Tool

Vaterlaus, Austin C. 09 June 2020 (has links)
One of the primary objectives of voice research is to better understand the biomechanics of voice production and how changes in properties of the vocal folds (VFs) affect voice ability and quality. Synthetic VF models provide a way to observe how changes in geometry and material property affect voice biomechanics. This thesis seeks to evaluate an approach of using a genetic algorithm to design synthetic VF models in three ways: first, through the development of a computationally cost-effective 3D vocal fold model; second, by creating and optimizing a variation of this model; and third, by validating the approach. To reduce computation times, a user-defined function (UDF) was implemented in low-fidelity 2D and 3D computational VF models. The UDF replaced the conventional meshed fluid domain with the mechanical energy equation. The UDF was implemented in the commercial finite element code ADINA and verified to produce results that were similar to those of 2D and 3D VF models with meshed fluid domains. Computation times were reduced by 86% for 2D VF models and 74% for 3D VF models while core vibratory characteristic changes were less than 5%. The results from using the UDF demonstrate that computation times could be reduced while still producing acceptable results. A genetic algorithm optimizer was developed to study the effects of altering geometry and material elasticity on frequency, closed quotient (CQ), and maximum flow declination rate (MFDR). The objective was to achieve frequency and CQ values within the normal human physiological range while maximizing MFDR. The resulting models enabled an exploration of trends between objective and design variables. Significant trends and aspects of model variability are discussed. The results demonstrate the benefit of using a structured model exploration method to create models with desirable characteristics. Two synthetic VF models were fabricated to validate predictions made by models produced by the genetic algorithm. Fabricated models were subjected to tests where frequency, CQ, and sound pressure level were measured. Trends between computational and synthetic VF model responses are discussed. The results show that predicted frequency trends between computational and synthetic models were similar, trends for closed quotient were inconclusive, and relationships between MFDR and sound pressure level remained consistent. Overall, while discrepancies between computational and synthetic VF model results were observed and areas in need of further study are noted, the study results provide evidence of potential for using the present optimization method to design synthetic VF models.
19

Explorative study for stochastic failure analysis of a roughened bi-material interface: implementation of the size sensitivity based perturbation method

Fukasaku, Kotaro 24 May 2011 (has links)
In our age in which the use of electronic devices is expanding all over the world, their reliability and miniaturization have become very crucial. The thesis is based on the study of one of the most frequent failure mechanisms in semiconductor packages, the delamination of interface or the separation of two bonded materials, in order to improve their adhesion and a fortiori the reliability of microelectronic devices. It focuses on the metal (-oxide) / polymer interfaces because they cover 95% of all existing interfaces. Since several years, research activities at mesoscopic scale (1-10µm) have proved that the more roughened the surface of the interface, i.e., presenting sharp asperities, the better the adhesion between these two materials. Because roughness exhibits extremely complex shapes, it is difficult to find a description that can be used for reliability analysis of interfaces. In order to investigate quantitatively the effect of roughness variation on adhesion properties, studies have been carried out involving analytical fracture mechanics; then numerical studies were conducted with Finite Element Analysis. Both were done in a deterministic way by assuming an ideal profile which is repeated periodically. With the development of statistical and stochastic roughness representation on the one hand, and with the emergence of probabilistic fracture mechanics on the other, the present work adds a stochastic framework to the previous studies. In fact, one of the Stochastic Finite Element Methods, the Perturbation method is chosen for implementation, because it can investigate the effect of the geometric variations on the mechanical response such as displacement field. In addition, it can carry out at once what traditional Finite Element Analysis does with numerous simulations which require changing geometric parameters each time. This method is developed analytically, then numerically by implementing a module in a Finite Element package MSc. Marc/Mentat. In order to get acquainted and to validate the implementation, the Perturbation method is applied analytically and numerically to the 3 point bending test on a beam problem, because the input of the Perturbation method in terms of roughness parameters is still being studied. The capabilities and limitations of the implementation are outlined. Finally, recommendations for using the implementation and for furture work on roughness representation are discussed.
20

Implementace části standardu SQL/MM DM pro asociační pravidla / Implementation of SQL/MM DM for Association Rules

Škodík, Zdeněk Unknown Date (has links)
This project is concerned with problems of knowledge discovery in databases, in the concrete then is concerned with an association rules, which are part of the system of data mining. By that way we try to get knowledge which we can´t find directly in the database and which can be useful. There is the description of SQL/MM DM, especially then all user-defined types given by standard for association rules as well as common types which create framework for data mining. Before the description of implementation these types, there is mentioned the instruments which are used for that - programming language PL/SQL and Oracle Data Mining support. The accuracy of implementation is verified by a sample application. In the conclusion, achieved results are evaluated and possible continuation of this work is mentioned.

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