Sometimes percentile points cannot be determined analytically. In such cases one has to resort to Monte Carlo techniques. In order to provide reliable and accurate results it is usually necessary to generate rather large samples. Thus the proper organization of the relevant data is of crucial importance. In this paper we investigate the appropriateness of heap-based data structures for the percentile point estimation problem. Theoretical considerations and empirical results give evidence of the good performance of these structures regarding their time and space complexity. (author's abstract) / Series: Forschungsberichte / Institut für Statistik

El proyecto de rediseño del sistema se ha realizado para mantener la operación activa y el flujo de medicamentos en la empresa. Si bien la farmacia o el almacén principal representa el 10% de los ingresos netos de la organización, es la principal área de apoyo para los principales servicios ofrecidos por la clínica a los clientes, ya que es responsable del suministro médico al consumidor interno y externo donde se interactúa con las actividades de la empresa. La implementación del proyecto consistió en calcular los lotes óptimos para cada línea de productos que se agruparon para un mejor tratamiento de los medicamentos: 700 artículos a 50 familias. Las líneas de productos para aquellos con características similares se definieron y se pudieron comprar a un proveedor en particular. Además, se establecieron descuentos para reducir los niveles de precios en la farmacia. En relación con el control de stock, se estableció el Plan Cíclico basado en el análisis Multicriterio ABC. Como parte del alcance del proyecto, se tomó una muestra con un nivel de confianza del 90% de la implementación del tipo de producto "A" total para aplicar durante 3 meses. En efecto, los pedidos de productos elegidos en el Plan Piloto cayeron del 80% al 12.5% de las ventas no atendidas por la falta de disponibilidad de existencias y los altos precios. Los resultados se lograron con la implementación de nuevos procedimientos de POES que involucran a los responsables de las áreas de la Clínica. / The System redesign project has been done in order to maintain active operation and flow of medicines in the company. Although Pharmacy - or main warehouse - accounts for 10% of net income in the organization, it is the main area of support for the main services offered by the clinic to the customers, because it is responsible for the medical supply to consumer internal and external interacting with the activities of the company. The implementation of the project was to calculate the optimal batch order for each product line, which were grouped for better treatment of medicines - 700 items to 50 families. Product lines for those with similar characteristics were defined and could be purchased from a particular vendor. Also, discounts were established to reduce the levels of prices in the pharmacy. In relation to stock control, counting Cyclical Plan based on analysis Multicriteria ABC was established. As part of the project scope, a sample at 90% confidence level of total product type “A” implementation to apply for 3 months was taken. In effect, orders for products chosen in the Pilot Plan fell from 80% to 12.5% of sales not served by non-availability of stock and high prices. The results were achieved with the implementation of new POES procedures involving those responsible for the areas in the Clinic. / Tesis

Most flows in nature and engineering are turbulent, and many are wall-bounded. Further, in turbulent flows, the turbulence generally has a large impact on the behavior of the flow. It is therefore important to be able to predict the effects of turbulence in such flows. The Navier-Stokes equations are known to be an excellent model of the turbulence phenomenon. In simple geometries and low Reynolds numbers, very accurate numerical solutions of the Navier-Stokes equations (direct numerical simulation, or DNS) have been used to study the details of turbulent flows. However, DNS of high Reynolds number turbulent flows in complex geometries is impractical because of the escalation of computational cost with Reynolds number, due to the increasing range of spatial and temporal scales. In Large Eddy Simulation (LES), only the large-scale turbulence is simulated, while the effects of the small scales are modeled (subgrid models). LES therefore reduces computational expense, allowing flows of higher Reynolds number and more complexity to be simulated. However, this is at the cost of the subgrid modeling problem. The goal of the current research is then to develop new subgrid models consistent with the statistical properties of turbulence. The modeling approach pursued here is that of "Optimal LES". Optimal LES is a framework for constructing models with minimum error relative to an ideal LES model. The multi-point statistics used as input to the optimal LES procedure can be gathered from DNS of the same flow. However, for an optimal LES to be truly predictive, we must free ourselves from dependence on existing DNS data. We have done this by obtaining the required statistics from theoretical models which we have developed. We derived a theoretical model for the three-point third-order velocity correlation for homogeneous, isotropic turbulence in the inertial range. This model is shown be a good representation of DNS data, and it is used to construct optimal quadratic subgrid models for LES of forced isotropic turbulence with results which agree well with theory and DNS. The model can also be filtered to determine the filtered two-point third-order correlation, which describes energy transfer among filtered (large) scales in LES. LES of wall-bounded flows with unresolved wall layers commonly exhibit good prediction of mean velocities and significant over-prediction of streamwise component energies in the near-wall region. We developed improved models for the nonlinear term in the filtered Navier-Stokes equation which result in better predicted streamwise component energies. These models involve (1) Reynolds decomposition of the nonlinear term and (2) evaluation of the pressure term, which removes the divergent part of the nonlinear models. These considerations significantly improved the performance of our optimal models, and we expect them to apply to other subgrid models as well. / text

The diploma thesis is focused on design and optimalization of digital octave and fraction-octave band filters. This thesis describe the behavior of filters in systems with fixed point arithmetics and investigate the impact of quantization coefficients for frequency response of filter. Filters, whitch has been designed, are implemented into simple software in C. Designed filters are in accordance with standard IEC 61260.