The Optimization of Repair Output Planning and Its Usage within Company KOS s.r.o.

Import 02/11/2016Tato práce se zabývá metodami využívanými při plánování a rozvrhování výroby, řeší problematiku optimalizace plánování opravárenských procesů železničních kolejových vozidel a jejich komponent. Na základě analýzy stavu byla východiska zvolené problematiky řešena především s důrazem na velikosti výrobních dávek a skladbu kusovníků technologického postupu. Navržená řešení jsou ve dvou úrovních. Optimalizace kusovníku a snížení velikosti dávek. Po propočtu a stanovení optimální velikosti dávky je prokázáno zvýšení dodavatelské spolehlivosti o 58%. Úpravou kusovníku lze při současné zakázkové náplni dosáhnout úspor v úrovni téměř 1 milionu Kč za rok.This work analyzes the methods used for planning and scheduling of production, deals with the optimization of planning the repairing processes of railway vehicles and their components. Based on the condition of the analysis, the possibilities of the given issue were mainly treated with emphasis to the amount of the production and the bill of materials’ structure of the technological processes. There are two suggested solutions to the matter, the optimization of the bill of materials and the reduction of the production. After setting the optimal amount of production, the supplying reliability rises by 58%. There can be saved as much as 1 million CZK per year with the optimization of the bill of materials.152 - Katedra podnikohospodářskávýborn

Lower bounds for approximation schemes for Closest String

In the Closest String problem one is given a family $\mathcal S$ of equal-length strings over some fixed alphabet, and the task is to find a string $y$ that minimizes the maximum Hamming distance between $y$ and a string from $\mathcal S$. While polynomial-time approximation schemes (PTASes) for this problem are known for a long time [Li et al., J. ACM'02], no efficient polynomial-time approximation scheme (EPTAS) has been proposed so far. In this paper, we prove that the existence of an EPTAS for Closest String is in fact unlikely, as it would imply that $\mathrm{FPT}=\mathrm{W}[1]$, a highly unexpected collapse in the hierarchy of parameterized complexity classes. Our proof also shows that the existence of a PTAS for Closest String with running time $f(\varepsilon)\cdot n^{o(1/\varepsilon)}$, for any computable function $f$, would contradict the Exponential Time Hypothesis

The new computer program for three dimensional relativistic hydrodynamical model

An effective computer program for three dimensional relativistic hydrodynamical model has been developed. It implements a new approach to the early hot phase of relativistic heavy-ion collisions. The computer program simulates time-space evolution of nuclear matter in terms of ideal-fluid dynamics. Equations of motions of hydrodynamics are solved making use of finite difference methods. Commonly-used algorithms of numerical relativistic hydrodynamics RHLLE and MUSTA-FORCE have been applied in simulations. To speed-up calculations, parallel processing has been made available for solving hydrodynamical equations. The test results of simulations for 3D, 2D and Bjorken expansion are reported in this paper. As a next step we plan to implement the hadronization algorithm by implementing the continuous particle emission for freeze-out and comparing it with Cooper-Frye formula.Comment: Quark Matter 2005 Poster Session Proceedin

Quantum Correlations in Two-Fermion Systems

We characterize and classify quantum correlations in two-fermion systems having 2K single-particle states. For pure states we introduce the Slater decomposition and rank (in analogy to Schmidt decomposition and rank), i.e. we decompose the state into a combination of elementary Slater determinants formed by mutually orthogonal single-particle states. Mixed states can be characterized by their Slater number which is the minimal Slater rank required to generate them. For K=2 we give a necessary and sufficient condition for a state to have a Slater number of 1. We introduce a correlation measure for mixed states which can be evaluated analytically for K=2. For higher K, we provide a method of constructing and optimizing Slater number witnesses, i.e. operators that detect Slater number for some states.Comment: 9 pages, some typos corrected and introduction modified, version to be published in Phys. Rev.

The Marriage of Heaven and Hell? Philip Pullman, C.S. Lewis, and the Fantasy Tradition

Closely scrutinizes Pullman’s frequent denials of his quite obvious debt to C.S. Lewis, finding the hidden nuances in Pullman’s statements by separating out his responses to Lewis as a reader, author, and critic. The inescapable conclusion is that not only is Pullman writing classic fantasy, he is in close agreement with Lewis on many points as a reader and critic

Comparison of an effectiveness of artificial neural networks for various activation functions

Activation functions play an important role in artificial neural networks (ANNs) because they break the linearity in the data transformations that are performed by models. Thanks to the recent spike in interest around the topic of ANNs, new improvements to activation functions are emerging. The paper presents the results of research on the effectiveness of ANNs for ReLU, Leaky ReLU, ELU, and Swish activation functions. Four different data sets, and three different network architectures were used. Results show that Leaky ReLU, ELU and Swish functions work better in deep and more complex architectures which are to alleviate vanishing gradient and dead neurons problems but at the cost of prediction speed. Swish function seems to speed up training process considerably but neither of the three aforementioned functions comes ahead in accuracy in all used datasets

Asteroseismology, standard candles and the Hubble Constant: what is the role of asteroseismology in the era of precision cosmology?

Classical Cepheids form one of the foundations of modern cosmology and the extragalactic distance scale, however, cosmic microwave background observations measure cosmological parameters and indirectly the Hubble Constant, H0, to unparalleled precision. The coming decade will provide opportunities to measure H0 to 2% uncertainty thanks to the GAIA satellite, JWST, ELTs and other telescopes using Cepheids and other standard candles. In this work, we discuss the upcoming role for variable stars and asteroseismology in calibrating the distance scale and measuring H0 and what problems exist in understanding these stars that will feedback on these measurements.Comment: 8 pages, summary of splinter session at IAU Symposium 301, Precision Asteroseismology, August 2013, Wroclaw, Polan

Prevalence of hypertension and major cardiovascular risk factors in healthy residents of a rural region in south-eastern Poland – 1997–2008/9

Introduction and objective The aim of this study was to show the prevalence of hypertension and major risk factors of cardiovascular disease among healthy adults in an agricultural region of south-eastern Poland, and the changes which have occurred in this area during the 12-year follow-up. Material and Methods 1,233, mostly rural inhabitants of Zamosc County without previous history of diabetes and CVD were subjected to analysis. Prevalence of hypertension and major cardiovascular risk factors were evaluated. Changes in the prevalence of risk factors between 1997 – 2008 were analyzed. Results 33.0% of the examined population are active smokers, and there was a 1.8-fold increase (p = 0.0009). The percentage of people with hypercholesterolemia between 1997 – 2008/9 increased almost 2-fold (p<0.0001) and now it is 62.3%. The number of people with high blood pressure decreased nearly by a half (46%, p<0001) and it is currently 25.8%. Improper waist circumference was observed in 32.8% of the population (33.1% women, 26.5% men). Abdominal obesity decreased among men (48%; p=0.0008) and rural residents (29%, p=0.01). In comparison with 1997, in 2008–2009, the cardiovascular risk assessed using SCORE tables increased. The percentage of people with high-risk (≥5%) almost tripled in the general population (p=0.0183) and increased 4-fold in men (p=0.0145). Conclusions Detection of hypertension in the rural region in which the survey was carried out is still too low. Actions against tobacco addiction should be a major component of health-education programmes for the rural areas of south-eastern Poland