141 research outputs found
Information System Assessment and Proposal of ICT Modification
Diplomová práce se zabývá hodnocením současného stavu reklamačního systému, návrhem změny celého systému a navržením modernějšího a efektivnějšího systému pro společnost Digilive s.r.o, implementací systému a jeho následným zhodnocením. Hlavním cílem systému je usnadnit práci zaměstnanců a zákazníků společnosti při vyřizování případných reklamací. Systém poskytuje dva základní typy uživatelských účtů. Zákazník bude moci zadávat reklamace popř. prohlížet údaje o svých reklamacích. Zaměstnanec společnosti může editovat veškeré údaje o reklamacích a zákaznících. Zaměstnanecká část je naimplementována s 5-dimenzionálním modelem přístupových práv.This graduation theses treats of the system for return mechandise authorization processing for the organization Digilive s.r.o. The system should improve and modernize work of the employees and the clients in the process of attending the sales return. The system will contain two kinds of the users. The client can make sales returns and view data about his sales returns. The employee can edit all data about the sales returns and the clients. The employee segment is implemented with the 5-dimension model access data.
Internet Used-Cars Shop
Tato bakalářská práce obsahuje analýzu, návrh a implementaci informačního systému internetového autobazaru. Systém eviduje zejména informace o automobilech, které autobazar nabízí k prodeji. O každém automobilu se uchovávají jeho základní údaje, údaje o bývalém majiteli, obecné informace o značce vozidla a údaje o změnách ceny automobilu. Do systému se můžou pomocí přihlašovacího jména a hesla přihlásit dva druhy uživatelů. Prvním z těchto uživatelů je klient autobazaru, kterému je dovoleno prohlížet katalog nabízených vozidel a případně provádět jejich rezervaci. A dále pak správce systému, který může všechny uchovávané záznamy editovat. Součásti autobazaru je diskusní fórum.This bachelor's thesis contains the analysis, the design and the information system implementation of the Internet used-cars shop. The system files predominantly information about the cars which the used-cars shop offers for sale. The system saves basic data about each car, the data about the former keeper, general information about the car producer and about the car price changes. Two kinds of users can log into the system with a specific password. The customer of the used-cars shop who is allowed to view the catalogue of offered cars and make a reservation. The second is the system administrator who can edit saved data. The used-cars shop forum is also available.
Comparison of Railway Vehicles Achieved Reliability
Import 03/08/2012Bakalářská práce se zabývá porovnáním dosažené spolehlivosti kolejových vozidela u vybraných řad lokomotiv. Vozidlový park tvoří 2 lokomotivy řady 727.7,stejný počet 2 lokomotiv řady 729.8 a 9 lokomotiv řady 724.8 pocházející z vlečky Třineckých železáren.This thesis presents a comparison of achieved reliability of rolling stock in selected series locomotives. Rolling stock consists of two locomotives number 727.7, the same number of two locomotives and 9 729.8 724.8 locomotives from siding Třinecké ironworks.342 - Institut dopravydobř
Topology Reduction for Approximate Symbolic Analysis
The paper deals with a procedure for approximate symbolic analysis of linear circuits based on simplifying the circuit model. The procedure consists of two main steps. First, network elements whose influence on the circuit function is negligible are completely removed, i.e. their parameters are removed from the resulting symbolic formula. The second step consists in modifying the voltage and current graphs in order to decrease the number of common spanning trees. The influence of each modification of the circuit model is ranked numerically. A fast method based on the use of cofactors is presented. It allows evaluating all the prospective simplifications using at most two matrix inversions per one frequency point
An experimental study of laboratory hybrid power system with the hydrogen technologies
This paper presents very small laboratory hybrid photovoltaic-hydrogen power system. The system was primarily assembled to verify the operability of the control algorithms and practical deployment of available commercial hydrogen technologies that are directly usable for storage of electricity produced from renewable energy sources in a small island system. This energetic system was installed and tested in Laboratory of fuel cells that is located in the university campus of VSB-Technical University of Ostrava. The energetic system consists of several basic components: a photovoltaic field, accumulators bank, water commercial electrolyzer and compact fuel cell system. The weather conditions recorded in two different weeks as model weather and solar conditions are used as case studies to test the energetic system and the results for two different cases are compared each other. The results show and illustrate selected behaviour curves of the power system and also average energy storage efficiency for accumulation subsystem based on hydrogen technologies or at the energetic system embedded components. On the basis of real measurement and its evaluation the ideal parameters of the photovoltaic field were calculated as well as the hydrogen technologies for supposed purpose and the power requirements
Rozšíření měřicího rozsahu pádové trubky na výzkumném energetickém centru
Better understanding of combustion process in large scale pulverized coal boilers can help with increasing of coal combustion efficiency and decreasing of pollutant emissions, such as nitrogen oxides and arguable carbon dioxide. This improvement cannot be performed without testing in labor-atory conditions. For this purpose, a new testing facility called the drop tube has been built in the Energy Research Center (ERC) of VSB-Technical University of Ostrava. This paper describes the methodology of pulverized coal thermo-kinetic properties determination with the use of the Drop Tube Test Facility and the first steps in improvement of this methodology. There is a new design of the sampling probe, an improved one, gas-tight double-wall design, implemented into the methodolo-gy lately. The intermediate space is vacuumed for the purpose of better isolating properties of the probe. Further, the probe is newly supplemented with a cryogenic control valve for smooth regulation of small flow rates of cooling media - liquid nitrogen. These innovations bring cooling media sav-ings, especially thanks to increased efficiency of this media’s cooling potential. Furthermore, smoother regulation allows a sample cooling in an accurately defined point.Lepší pochopení spalovacího procesu ve velkých práškových uhelných kotlích může pomoci se zvyšováním efektivity spalování uhlí a snížením emisí znečišťujících látek jako jsou oxidy dusíku a diskutabilní oxid uhličitý. Tato zlepšení není možné provést bez laboratorního zkoušení. Pro tento účel bylo na Výzkumném energetickém centru VŠB-Technické univerzity Ostrava postaveno nové testovací zařízení nazvané pádová trubka. Tento článek popisuje metodiku stanovení termo-kinetických vlastností uhelného prášku s použitím pilotního testovacího zařízení pádové trubky a popisuje první kroky ke zlepšení této metodiky. Do metodiky je nově začleněna druhá vylepšená verze odběrové chladící sondy, která je vyhotovena v plynotěsném dvouplášťovém provedení. Mezi-prostor je pro zlepšení izolačních vlastností sondy evakuován. Dále je sonda nově doplněna kryogenním regulačním ventilem pro jemně nastavitelné dávkování chladícího média – tekutého dusíku. Tyto inovace přináší úspory ve spotřebě chladícího media zejména díky zvýšení účinnosti chladícího potenciálu tohoto media. Dále plynulejší regulace umožňuje zchlazení vzorku v přesně definovaném místě
Is Primary Fixation with the Sliding Hip Screw Introduced into the Non-ideal Position Sufficient for Stable Pertrochanteric Fracture Stabilisation? A Biomechanical Evaluation and Experimental Study
Purpose: Proximal femoral fractures are most commonly sustained fractures in the elderly. The one of the current treatment option of stable pertrochanteric fracture is Sliding Hip Screw. The necessity of a repeat surgery, due to the failure of the first osteosynthesis, may jeopardize the patient's life. Common causes of a failure include: fracture pattern, implant position, implant's properties and the bone quality. Each screw position variant results in damage to various load-bearing bone structures during healing. The aim of this study was analysis of different screw positions with focuse on the risky position with the need of the intra-operative implant reintroduction.Methods: With the use of a numerical computational model and finite element methods, the authors analyzed five positions of Sliding Hip Screw in the proximal femur, with the objective of determining positions with an increased risk of failure. The ideal position was in the middle third of the femoral neck anchored subchondrally.Results: In model situations, it has been shown that in stable fractures the screw position in proximal third of the femoral neck significantly increased the strain of the plate and screw and may lead to the osteosynthesis failure. The other analysed positions do not significantly increase the risk of failure for entire fixation. Conclusions: It is not necessary to re-introduce Sliding Hip Screw into the ideal position (except placening in the proximal third of the neck) during the surgery. Damage to load-bearing structures relative to various implant placements does not impact the resultant overall fixation stability
Constraining models of twin peak quasi-periodic oscillations with realistic neutron star equations of state
Twin-peak quasi-periodic oscillations (QPOs) are observed in the X-ray
power-density spectra of several accreting low-mass neutron star (NS) binaries.
In our previous work we have considered several QPO models. We have identified
and explored mass-angular-momentum relations implied by individual QPO models
for the atoll source 4U 1636-53. In this paper we extend our study and confront
QPO models with various NS equations of state (EoS). We start with simplified
calculations assuming Kerr background geometry and then present results of
detailed calculations considering the influence of NS quadrupole moment
(related to rotationally induced NS oblateness) assuming Hartle-Thorne
spacetimes. We show that the application of concrete EoS together with a
particular QPO model yields a specific mass-angular-momentum relation. However,
we demonstrate that the degeneracy in mass and angular momentum can be removed
when the NS spin frequency inferred from the X-ray burst observations is
considered. We inspect a large set of EoS and discuss their compatibility with
the considered QPO models. We conclude that when the NS spin frequency in 4U
1636-53 is close to 580Hz we can exclude 51 from 90 of the considered
combinations of EoS and QPO models. We also discuss additional restrictions
that may exclude even more combinations. Namely, there are 13 EOS compatible
with the observed twin peak QPOs and the relativistic precession model.
However, when considering the low frequency QPOs and Lense-Thirring precession,
only 5 EOS are compatible with the model.Comment: 12 pages, 9 figures, 3 tables, accepted for publication in The
Astrophysical Journa
Mass of the active galactic nucleus black hole XMMUJ134736.6+173403
A recent study of the X-ray source XMMUJ134736.6+173403 has revealed a strong
quasi-periodic modulation of the X-ray flux. The observation of two
quasiperiodic oscillations (QPOs) that occur on a daily timescale and exhibit a
3:1 frequency ratio strongly supports the evidence for the presence of an
active galactic nucleus black hole (AGN BH). Assuming the orbital origin of
QPOs we calculate the upper and lower limit on AGN BH mass M arriving at
. Comparing that to mass estimates of other
sources, MMUJ134736.6+173403 appears to be the most massive source with
commensurable QPO frequencies, and its mass represents the current
observational upper limit on AGN BH mass based on QPO observations. We note it
will be crucial for the falsification of particular resonance models of QPOs
whether only single QPO with frequency that completes the harmonic sequence
3:2:1 is found in this source, or whether there is a new different pair of QPOs
with frequencies in the 3:2 ratio. The former case would agree with the
prediction of the 3:2 epicyclic resonance model and black hole mass
, where a is a dimensionless BH
spin.Comment: 5 pages, 2 figures, 1 table, accepted for publication in A&A Letters,
minor corrections to the text to match published versio
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