Múltiples factores que afectan el uso correcto de la información contable en una toma de decisiones compleja

Tesis inédita de la Universidad Complutense de Madrid, Facultad de Ciencias Económicas y Empresariales, leída el 12-11-2020The aim of this doctoral thesis is to explore the audit issues that affect the quality of the auditor's opinion and their decision making. We answer many research questions regarding the correlation of audit issues and its effect on the quality. The general outcome indicates that there was a close relationship between the financial crisis and auditing, due to the influence of dysfunctional behavior on audit quality which was among those relations whose impact on the crisis.This issue has been interesting in recent years because there have been a growing number of bankruptcies due to the financial crisis whether direct or indirect issues that affect the quality of the auditor's opinion where business management has failed to warn of its impact on the business...El objetivo de esta tesis doctoral es estudiar los problemas que afectan la calidad de la opinión del auditor y su toma de decisiones. Respondemos a muchas interrogantes de investigación sobre la correlación existente entre los problemas de auditoría y sus efectos en la calidad. El resultado general indica que hay una estrecha relación entre la crisis financiera y la auditoría, debido a la influencia del comportamiento disfuncional en la calidad de auditoría que tuvo un impacto en la crisis. Este tema ha sido interesante en los últimos años debido al número creciente de bancarrotas por la crisis financiera, ya sean problemas que afectan directa o indirectamente la calidad de la opinión del auditor o donde la dirección de la empresa no ha advertido su impacto...Fac. de Ciencias Económicas y EmpresarialesTRUEunpu

Rotor Position Estimation of a Pseudo Direct Drive PM machine using Extended Kalman Filter

The paper describes an improved method to control a Pseudo Direct Drive (PDD) permanent magnet machine with only one sensor on the low-speed rotor (LSR). Due to the magnetic coupling between the two rotors, the PDD machine exhibits low stiffness and non-linear torque transmission characteristics, and hence, the position of the high-speed rotor (HSR) cannot be determined using a simple gear ratio relationship. An extended kalman filter is proposed to accurately estimate the position of the HSR which is used to provide electronic commutation for the drive. The technique has been implemented on a prototype PDD subjected to various speed and load torque profiles

Relative Booster Ideals of Distributive p-algebras

In this article, the definition and characterization of relative booster ideals in distributive p-algebras are given. The relationship between disjunctive relative booster ideals and normal relative booster ideals is established in the distributive p-algebras. A lattice congruence relation defined via the relative boosters is given and its quotient lattice structure is obtained

Inverted Beta Lindley Distribution

In this paper, a three-parameter continuous distribution, namely, Inverted Beta-Lindley (IBL) distribution is proposed and studied. The new model turns out to be quite flexible for analyzing positive data and has various shapes of density and hazard rate functions. Several statistical properties associated with this distribution are derived. Moreover, point estimation via method of moments and maximum likelihood method are studied and the observed information matrix is derived. An application of the new model to real data shows that it can give consistently a better fit than other important lifetime models

Influence of control structures and load parameters on performance of a pseudo direct drive

The paper describes an in-depth and systematic analysis of a pseudo direct drive permanent magnet machine in closed loop control. Due to the torque being transmitted from the high-speed rotor (HSR) to the low-speed rotor (LSR), through a relatively low stiffness magnetic gear with non-linear characteristics, speed oscillations appear in the drive output with a conventional proportional integral (PI) controller. Therefore two candidate controllers have been proposed as an alternative to the PI control and all controllers have been optimally tuned with a genetic algorithm against a defined criterion. Furthermore, closed loop models are established in the complex frequency domain to determine the system damping and the cause of the oscillations. Consequently, the best controller structure that improves the dynamic behaviour of the system in terms of speed tracking and disturbance rejection could be identified, based on the frequency domain analysis. Experimental results are presented to validate the analysis and the proposed control technique

Software Protection

A computer system's security can be compromised in many ways a denial-of-service attack can make a server inoperable, a worm can destroy a user's private data, or an eavesdrop per can reap financial rewards by inserting himself in the communication link between a customer and her bank through a man-in-the-middle (MITM) attack. What all these scenarios have in common is that the adversary is an untrusted entity that attacks a system from the outside-we assume that the computers under attack are operated by benign and trusted users. But if we remove this assumption, if we allow anyone operating a computer system- from system administrators down to ordinary users-to compromise that system's security, we find ourselves in a scenario that has received comparatively little attention. Methods for protecting against MATE attacks are variously known as anti-tamper techniques, digital asset protection, or, more

The Second-Generation Shifted Boundary Method and Its Numerical Analysis

Recently, the Shifted Boundary Method (SBM) was proposed within the class of unfitted (or immersed, or embedded) finite element methods. By reformulating the original boundary value problem over a surrogate (approximate) computational domain, the SBM avoids integration over cut cells and the associated problematic issues regarding numerical stability and matrix conditioning. Accuracy is maintained by modifying the original boundary conditions using Taylor expansions. Hence the name of the method, that {\it shifts} the location and values of the boundary conditions. In this article, we present enhanced variational SBM formulations for the Poisson and Stokes problems with improved flexibility and robustness. These simplified variational forms allow to relax some of the assumptions required by the mathematical proofs of stability and convergence of earlier implementations. First, we show that these new SBM implementations can be proved asymptotically stable and convergent even without the rather restrictive assumption that the inner product between the normals to the true and surrogate boundaries is positive. Second, we show that it is not necessary to introduce a stabilization term involving the tangential derivatives of the solution at Dirichlet boundaries, therefore avoiding the calibration of an additional stabilization parameter. Finally, we prove enhanced $L^{2}$-estimates without the cumbersome assumption - of earlier proofs - that the surrogate domain is convex. Instead we rely on a conventional assumption that the boundary of the true domain is smooth, which can also be replaced by requiring convexity of the true domain. The aforementioned improvements open the way to a more general and efficient implementation of the Shifted Boundary Method, particularly in complex three-dimensional geometries. We present numerical experiments in two and three dimensions.Comment: 28 pages, 6 figures, 4 table

The second-generation Shifted Boundary Method and its numerical analysis

Recently, the Shifted Boundary Method (SBM) was proposed within the class of unfitted (or immersed, or embedded) finite element methods. By reformulating the original boundary value problem over a surrogate (approximate) computational domain, the SBM avoids integration over cut cells and the associated problematic issues regarding numerical stability and matrix conditioning. Accuracy is maintained by modifying the original boundary conditions using Taylor expansions. Hence the name of the method, that shifts the location and values of the boundary conditions. In this article, we present enhanced variational SBM formulations for the Poisson and Stokes problems with improved flexibility and robustness. These simplified variational forms allow to relax some of the assumptions required by the mathematical proofs of stability and convergence of earlier implementations. First, we show that these new SBM implementations can be proved asymptotically stable and convergent even without the rather restrictive assumption that the inner product between the normals to the true and surrogate boundaries is positive. Second, we show that it is not necessary to introduce a stabilization term involving the tangential derivatives of the solution at Dirichlet boundaries, therefore avoiding the calibration of an additional stabilization parameter. Finally, we prove enhanced L2-estimates without the cumbersome assumption – of earlier proofs – that the surrogate domain is convex. Instead we rely on a conventional assumption that the boundary of the true domain is smooth, which can also be replaced by requiring convexity of the true domain. The aforementioned improvements open the way to a more general and efficient implementation of the Shifted Boundary Method, particularly in complex three-dimensional geometries. We complement these theoretical developments with numerical experiments in two and three dimensions