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Racionalizace výrobní linky / Rationalization of the production lineStraka, Jiří January 2019 (has links)
This masters thesis optimises production of the step plates (which are parts of the sliding steps systems used in tramways, subways, hi-speed trains etc.) to increase the production rate to meet customers demand. The purpose of the work was reached by detailed analysis of the production process followed by evaluation of the results which led to the list of the possible solutions. The solution with the greatest time improvement was chosen and explained in detail.
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Vzdálené monitorování motorových vozidel / Remote car monitoringStrecker, Zbyněk January 2009 (has links)
The main goal of this work is to design an efficient and cheap car-alarm with an electricity consumption not exceeding 1mA in the stand-by mode. The first part focuses on the conception of the car-alarm. As the best option - GPS/GSM car-alarm conception is chosen. Then the design of the switching power supply, communication via RS232 with the GSM module, and GPS module, I2C communication with accelerometer and timer IC, and design of the display module are described. Furthermore, the process of how to code/decode sms into the PDU format is also discussed in this part. The second part provides some basic empirical characteristics of the switching power supply (efficiency, switching frequency etc.). Then the owchart of the main loop is explained, followed by an example of the sms which the car-alarm sends in case a car theft. Explanation of how to set up timer, acceleration threshold and the time between the check of the sms commads is the subject of the next section. Fifth part deals with the installation the car-alarm into a car which is illustrated on the Skoda Favorit example. Total costs and also different cost items are listed just before concluding and suggesting some potential improvements of the device.
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Marketingová strategie pro firmu OHL ŽS, a.s. / Marketing strategy for company OHL ŽS, Inc.Peterková, Eva January 2008 (has links)
Master´s thesis describes current economic state of the OHL ŽS, a.s., analyzes the makronomics and mikronomics surrounding. On the basis of this analysis I suggest arrangements that will lead to achieve the required marketing´s targets.
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Contamination de l’environnement marin par des produits de soin et des produits pharmaceutiques : molécules mères et métabolites / Contamination of the marine environment by personal care products and pharmaceuticals : parents and metabolitesPicot-Groz, Marina 07 March 2017 (has links)
La contamination des milieux côtiers par des contaminants émergents est une préoccupation sociétale récente ce qui explique le peu de données disponibles, à ce jour dans ce milieu. Pourtant, certains de ces contaminants sont susceptibles de générer des effets écotoxiques sur les organismes aquatiques du milieu marin. Trois voies d’introduction de contaminants dans l’environnement marin sont communément identifiées : l’apport indirect depuis les bassins versants à travers les fleuves côtiers et les apports directs soit lors d’activités récréatives, soit par le rejet d’effluents d’eaux usées. Ce travail de thèse s’est focalisé sur les apports directs. L’objectif principal de cette thèse a été d’établir un état des lieux de la contamination du milieu marin par les pharmaceutiques et les produits de soin (PPCP) et d’évaluer leur apport par les activités récréatives et les eaux usées. Pour évaluer l’impact des activités de baignade sur la contamination marine, des analyses d’occurrence de filtres UV, substances principalement contenues dans les crèmes solaires ont été réalisées en zones côtières dans l’eau de mer et dans des organismes aquatiques, les moules. Les résultats de ces mesures ont montré des variations saisonnières et intra journalières de la concentration de filtres UV dans le milieu côtier, confirmant l’apport de ces substances par les activités récréatives. Le traitement par les stations d’épuration (STEP) ne permet pas une élimination complète de certains PPCP persistants. Pour évaluer l’impact des effluents de STEP sur les milieux récepteurs, des molécules pharmaceutiques et leurs formes conjuguées ont été recherchées dans des effluents domestiques et d’hôpitaux et en entrée et sortie de STEP. Les concentrations faibles de molécules conjuguées retrouvées en sortie de STEP ont démontré que les molécules conjuguées ne représentaient pas des marqueurs pertinents de la contamination marine par les eaux usées. Cependant les eaux usées traitées de manière partielle sont parfois rejetées directement dans le milieu marin via des émissaires en mer d’où l’importance de l’évaluation de cet apport. Les données acquises sur l’occurrence d’une molécule pharmaceutique, la venlafaxine et ses produits de transformation en sortie d’émissaire en mer a permis de confirmer la présence de ses molécules dans le milieu marin et l’importance d’inclure les métabolites dans les programmes de surveillance de la contamination marine. / Contamination of coastal environments by emerging contaminants is a recent societal concern, explaining the lack of data available today in this environment. However, some of these contaminants are likely to cause ecotoxic effects on aquatic organisms in the marine environment. Three ways of contaminants introduction into the marine environment are commonly identified: indirect inputs with catchments through coastal rivers and direct inputs through recreational activities and through the wastewater effluents. This work focused on direct contributions. The main objective of this thesis was to assess the current state of the contamination of the marine environment by pharmaceuticals and care products (PPCP) and to evaluate their contribution by the recreational activities and the wastewater releases. In order to assess the impact of bathing activities on marine contamination, occurrence studies of UV filters, substances mainly contained in sunscreens, have been carried out in coastal areas in seawater and in aquatic organisms and more precisely in mussels. The results showed seasonal and intra-day variations in the concentration of UV filters in the coastal environment, confirming that recreational activities contribute to introduce these substances in marine environment. Wastewater treatment plants (WWTP) does not allow the complete elimination of some persistent PPCPs. To evaluate the impact of WWTP effluents on the receiving environment, pharmaceuticals and their conjugated forms were analyzed in domestic and hospital effluents and in WWTP influents and effluents. The low concentrations of conjugated found in WWTP effluents demonstrated that the conjugated were not represented relevant markers of marine contamination by wastewater. However, partially treated wastewater is sometimes discharged directly into the marine environment via marine outfalls, hence the importance of assessing this input. The data on the occurrence of a pharmaceutical molecule, venlafaxine and its transformation products at marine outfall, confirmed the presence of its molecules in the marine environment and the importance of including metabolites in monitoring programs of marine contamination.
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One-Step and Two-Step Advertising Information Flows on Social Media: How Chinese College Students Find and Distribute Information about Advertised Products Using RenrenXu, Jiaojiao 24 September 2014 (has links)
No description available.
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Electromigration induced step instabilities on silicon surfacesGibbons, Brian J., Jr 22 September 2006 (has links)
No description available.
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On Group-Sequential Multiple Testing Controlling Familywise Error RateFu, Yiyong January 2015 (has links)
The importance of multiplicity adjustment has gained wide recognition in modern scientific research. Without it, there will be too many spurious results and reproducibility becomes an issue; with it, if overtly conservative, discoveries will be made more difficult. In the current literature on repeated testing of multiple hypotheses, Bonferroni-based methods are still the main vehicle carrying the bulk of multiplicity adjustment. There is room for power improvement by suitably utilizing both hypothesis-wise and analysis- wise dependencies. This research will contribute to the development of a natural group-sequential extension of the classical stepwise multiple testing procedures, such as Dunnett’s stepdown and Hochberg’s step-up procedures. It is shown that the proposed group-sequential procedures strongly control the familywise error rate while being more powerful than the recently developed class of group-sequential Bonferroni-Holm’s procedures. Particularly in this research, a convexity property is discovered for the distribution of the maxima of pairwise null P-values with the underlying test statistics having distributions such as bivariate normal, t, Gamma, F, or Archimedean copulas. Such property renders itself for an immediate use in improving Holm’s procedure by incorporating pairwise dependencies of P-values. The improved Holm’s procedure, as all stepdown multiple testing procedures, can also be naturally extended to group-sequential setting. / Statistics
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Multiscale modeling using goal-oriented adaptivity and numerical homogenizationJhurani, Chetan Kumar 16 October 2009 (has links)
Modeling of engineering objects with complex heterogeneous material
structure at nanoscale level has emerged as an important research problem. In
this research, we are interested in multiscale modeling and analysis of mechanical
properties of the polymer structures created in the Step and Flash Imprint
Lithography (SFIL) process. SFIL is a novel imprint lithography process designed
to transfer circuit patterns for fabricating microchips in low-pressure
and room-temperature environments. Since the smallest features in SFIL are
only a few molecules across, approximating them as a continuum is not completely
accurate. Previous research in this subject has dealt with coupling
discrete models with continuum hyperelasticity models. The modeling of the
post-polymerization step in SFIL involves computing solutions of large nonlinear
energy minimization problems with fast spatial variation in material properties. An equilibrium configuration is found by minimizing the energy of
this heterogeneous polymeric lattice.
Numerical solution of such a molecular statics base model, which is
assumed to describe the microstructure completely, is computationally very
expensive. This is due to the problem size – on the order of millions of degrees
of freedom (DOFs). Rapid variation in material properties, ill-conditioning,
nonlinearity, and non-convexity make this problem even more challenging to
solve.
We devise a method for efficient approximation of the solution. Combining
numerical homogenization, adaptive finite element meshes, and goaloriented
error estimation, we develop a black-box method for efficient solution
of problems with multiple spatial scales. The purpose of this homogenization
method is to reduce the number of DOFs, find locally optimal effective material
properties, and do goal-oriented mesh refinement. In addition, it smoothes
the energy landscape.
Traditionally, a finite element mesh is designed after obtaining material
properties in different regions. The mesh has to resolve material discontinuities
and rapid variations. In our approach, however, we generate a sequence
of coarse meshes (possibly 1-irregular), and homogenize material properties on
each coarse mesh element using a locally posed constrained convex quadratic
optimization problem. This upscaling is done using Moore-Penrose pseudoinverse
of the linearized fine-scale element stiffness matrices, and a material independent
interpolation operator. This requires solution of a continuous-time Lyapunov equation on each element. Using the adjoint solution, we compute
local error estimates in the quantity of interest. The error estimates also drive
the automatic mesh adaptivity algorithm. The results show that this method
uses orders of magnitude fewer degrees of freedom to give fast and approximate
solutions of the original fine-scale problem.
Critical to the computational speed of local homogenization is computing
Moore-Penrose pseudoinverse of rank-deficient matrices without using
Singular Value Decomposition. To this end, we use four algorithms, each
having different desirable features. The algorithms are based on Tikhonov
regularization, sparse QR factorization, a priori knowledge of the null-space
of the matrix, and iterative methods based on proper splittings of matrices.
These algorithms can exploit sparsity and thus are fast.
Although the homogenization method is designed with a specific molecular
statics problem in mind, it is a general method applicable for problems
with a given fine mesh that sufficiently resolves the fine-scale material properties.
We verify the method using a conductivity problem in 2-D, with chessboard
like thermal conductivity pattern, which has a known homogenized
conductivity. We analyze other aspects of the homogenization method, for
example the choice of norm in which we measure local error, optimum coarse
mesh element size for homogenizing SFIL lattices, and the effect of the method
chosen for computing the pseudoinverse. / text
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Övervakningssystem för vindkraftverk : Monitoring system for wind turbinesJebur, Mariam January 2016 (has links)
This report describes how a new and modern monitoring system is crea- ted for a wind turbine. Elvira Vind AB is a company that has an old operating surveillance system manufactured in 1992. A need has arisen with the owner of the company and are looking for a simple and smooth system that monitors the situation in a wind turbine. Therefore, a system is created that can transmit data wireless- ly through a GSM-module. The system must be able to sense temperature, vibration and sound levels. Also a camera has to take a picture when it de- tects vibration and display the values of the sensors in a web site. The system must also be powered during a power failure, therefore a voltage regulator and a charging circuit was made in the circuit board. The goal of this project is to create a sensor-based monitoring system for a wind turbine and to see the sensor readings wirelessly and displayed in a web site. The report describes how the electronic circuit board has been created and which methods have been used for each sensor in this project. There is also a description of how to use the system for both software and hardware. / Övervakningssystem för vindkraftverk
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Improve the Convergence Speed and Stability of Generative Adversarial NetworksZou, Xiaozhou 26 April 2018 (has links)
In this thesis, we address two major problems in Generative Adversarial Networks (GAN), an important sub-field in deep learning. The first problem that we address is the instability in the training process that happens in many real-world problems and the second problem that we address is the lack of a good evaluation metric for the performance of GAN algorithms. To understand and address the first problem, three approaches are developed. Namely, we introduce randomness to the training process; we investigate various normalization methods; most importantly we develop a better parameter initialization strategy to help stabilize training. In the randomness techniques part of the thesis, we developed two randomness approaches, namely the addition of gradient noise and the batch random flipping of the results from the discrimination section of a GAN. In the normalization part of the thesis, we compared the performances of the z-score transform, the min-max normalization, affine transformations and batch normalization. In the most novel and important part of this thesis, we developed techniques to initialize the GAN generator section with parameters that can produce a uniform distribution on the range of the training data. As far as we are aware, this seemingly simple idea has not yet appeared in the extant literature, and the empirical results we obtain on 2-dimensional synthetic data show marked improvement. As to better evaluation metrics, we demonstrate a simple yet effective way to evaluate the effectiveness of the generator using a novel "overlap loss".
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