15 research outputs found

    Implementation of Mortar elements and the Internodes method for dissimilar meshes in the PERMON software package

    Get PDF
    Tato diplomová práce je zaměřena na Mortar metodu a metodu Internodes pro lineární eliptické okrajové úlohy ve 2D. Tyto metody se používají pro lepení nekonformních diskretizačních sítí v metodách rozložení oblastí. Pochopením a praktickou implementací těchto metod můžeme rozšířit funkcionalitu stávajících metod, které používají "pěkné" konformní sítě. Obě metody jsou zde popsány teoreticky i prakticky. Nakonec porovnáme a zhodnotíme klíčové vlastnosti obou metod.This diploma thesis is focused on Mortar method and Internodes for linear elliptic boundary problems in 2D. These methods are used for nonconforming domain coupling in domain decomposition methods. After learning and implementing these methods, we can extend functionality of existing methods for nonconforming cases. We will also review and compare each of these methods at the end of this thesis.470 - Katedra aplikované matematikyvýborn

    The hybrid parallelization of TFETI-1 method

    Get PDF
    Import 22/07/2015Práce se zabývá hybridní paralelizací TFETI-1 metody implementované v knihovně PermonFLLOP. Nejdříve představuje různé paralelní programovací modely a způsoby hybridní paralelizace. Poté uvádí možné výhody hybridní paralelizace v porovnání s čistou MPI paralelizací. Dále pak tato práce analyzuje balíčky poskytující přímé řešiče, které hrají klíčovou roli v implementaci TFETI-1, z hlediska vhodnosti pro hybridní paralelizaci. Nová implementace TFETI-1 metody rozšiřuje stávající implementaci paralelizovanou čistě pomocí MPI. Díky ní je možné držet data více podoblastí na jednom MPI procesu. To umožnuje využít dobrých vlastností numerické škálovatelnosti FETI metod. V numerických experimentech je pak testována numerická škálovatelnost a vliv hybridní paralelizace.The thesis deals with the hybrid parallelization of the TFETI-1 method which is implemented in the library PermonFLLOP. At first, the thesis presents various parallel programming models and ways of the hybrid parallelization. There are listed the possible benefits of the hybrid parallelization compared with the pure MPI parallelization. Then the thesis analyzes the packages providing direct solvers, which have important role in the TFETI-1 implementation, in terms of suitability for hybrid parallelization. New implementation extends the existing pure MPI implementation. With this extension, data of more subdomains can be now stored per one MPI process. This allows the use of good properties of the numerical scalability of the FETI methods. In numerical experiments, the numerical scalability and the impact of hybrid parallelization are tested.470 - Katedra aplikované matematikyvýborn

    Non-monotone projected gradient method in linear elasticity contact problems with given friction

    Get PDF
    We are focusing on the algorithms for solving the large-scale convex optimization problem in linear elasticity contact problems discretized by Finite Element method (FEM). The unknowns of the problem are the displacements of the FEM nodes, the corresponding objective function is defined as a convex quadratic function with symmetric positive definite stiffness matrix and additional non-linear term representing the friction in contact. The feasible set constraints the displacement subject to non-penetration conditions. The dual formulation of this optimization problem is well-known as a Quadratic Programming (QP) problem and can be considered as a most basic non-linear optimization problem. Understanding these problems and the development of efficient algorithms for solving them play the crucial role in the large-scale problems in practical applications. We shortly review the theory and examine the behavior and the efficiency of Spectral Projected Gradient method modified for QP problems (SPG-QP) on the solution of a toy example in MATLAB environment.Web of Science1220art. no. 867

    Study of optimal cam design of dual-axle spring-loaded camming device

    Get PDF
    The spring-loaded camming device (SLCD), also known as "friend", is a simple mechanism used to ensure the safety of the climber through fall prevention. SLCD consists of two pairs of opposing cams rotating separately, with one (single-axle SLCD) or two (dual-axle SLCD) pins connecting the opposing cams, a stem, connected to the pins, providing the attachment of the climbing rope, springs, which simultaneously push cams to a fully expanded position, and an operating element controlling the cam position. The expansion of cams is thus adaptable to allow insertion or removal of the device into/from a rock crack. While the pins, stem, operating element, and springs can be considered optimal, the (especially internal) shape of the cam allows space for improvement, especially where the weight is concerned. This paper focuses on optimizing the internal shape of the dual-axle SLCD cam from the perspective of the weight/stiffness trade-off. For this purpose, two computational models are designed and multi-step topology optimization (TOP) are performed. From the computational models' point of view, SLCD is considered symmetric and only one cam is optimized and smoothened using parametric curves. Finally, the load-bearing capacity of the new cam design is analyzed. This work is based on practical industry requirements, and the obtained results will be reflected in a new commercial design of SLCD.Web of Science148art. no. 194

    THE USE OF ELECTRONIC SURVEILLANCE AND PERFORMANCE MEASURES IN THE WORKPLACE: A QUALITATIVE INVESTIGATION

    Get PDF
    Electronic workplace surveillance takes many forms. It includes CCTV, recording telephone conversations, employee ID cards, and electronically gathering and measuring work performance. The increased incidences of electronic surveillance have had a number of effects on employees. This research concentrated on the use of quantified electronic performance measurement. It specifically examined the impact on managers and managing. It examined surveillance from an employment relationship perspective, taking as its primary lens that of exchange and exchange theory. The research demonstrated that the exchange relationships managers have with other managers, workers, or employers, as part of the psychological contract, is being compromised. Managers feel under pressure to manage based on the surfeit of electronic measures rather than by using innate or acquired management skills. Many managers in this research are no longer managers in the conventional sense; instead, they have become “Performance Intermediary Executives” invariably reliant on a plethora of electronic measures provided for them to help them manage successfully. Managers have also started questioning the equitable nature of the psychological contract between them and their employer/line manager. The result of this equity disjuncture was made manifest by the subtle forms of resistance used on a daily basis. Managers are being led down a managerial path leading to further resistance and inequitable employment and exchange relationships. This research suggests that claimed improvements in performance and performance management using electronic surveillance could be wiped out by poor and de-professionalised management. Organisations should be aware that surveillance for surveillance sake is not necessarily always the best way forward. Electronic workplace surveillance is not intrinsically all good or all bad, but judging from the findings in this research, its impact is broadly perceived by managers negatively, which is not good for all parties in the employment relationship

    Selected Papers Compiled from Presentations - Leningrad Task Force Meeting, May 24-29, 1982, Leningrad, USSR

    Get PDF
    In line with the selected methodology, the Management and Technology area at IIASA decided to have the Innovation Management Task concentrate on sectors in an attempt to analyze the situation at this level of the economy before making any aggregations or conclusions relevant to management. In order to properly cover industry, it was suggested that branches that are at differing stages or that display different kinds of development be chosen for the study. Electrotechnology or power electrical engineering was one of the branches selected being an example of mature industry. The task force meeting held in Leningrad from May 24-29, 1982, was the first attempt LO scan problems in this branch and gain some kind of understanding as to the research that has been performed. The event was a multiobjective undertaking intended to identify the interest in this field. potential collaborators, and relevant issues. Due to the unique opportunity of becoming acquainted with the work of Soviet scientists, the papers presented were not only by researchers and scholars in this field, but also by decision makers on the different levels of management. For the first time, several issues are exposed for the English speaker, thus, rendering a service to the English speaking community of researchers, and enhancing the contacts with collaborators in socialist countries. The papers are arranged into four sections, each devoted to issues that can be viewed as interesting topics for further research. The discussion, found in the back of the proceedings as Appendix A, reflects the character of the productive and creative environment at the meeting. The reader must bear in mind that this is only an attempt to reflect the "milieu" as accurately as possible. It almost seems impossible to express the true working atmosphere created by the participants. The task force meeting was also the first attempt to see if IIASA could prepare a program of interest to representatives of industrial enterprises. Many questions were raised and discused. The reactions expressed by the participants at the meeting and later on significantly prove that the answer is generally positive

    Technical Workshop: Advanced Helicopter Cockpit Design

    Get PDF
    Information processing demands on both civilian and military aircrews have increased enormously as rotorcraft have come to be used for adverse weather, day/night, and remote area missions. Applied psychology, engineering, or operational research for future helicopter cockpit design criteria were identified. Three areas were addressed: (1) operational requirements, (2) advanced avionics, and (3) man-system integration
    corecore