18420 research outputs found
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Quantum Chemical Investigation of the Geometric and Electronic Structure of the 3-Amidino-2-Brombenzanthrone. Absorption and Fluorescent Spectra Prediction
No full textChemical Interesterification of Rapeseed Oil with Ethyl Acetate Using t-Butanolic Potassium Butoxide
No full textInvestigation of Polarization Mode Dispersion Influence to Different Optical Signal Modulation Formats
No full textIncreasing data rates in the fiber optics transmission systems leads to more new limiting factors which complicates the signal transmission. One of such factors is the optical fiber birefringence induced polarization mode dispersion (PMD). Although PMD value in typical standard single mode fiber is quite low (less than 0.2 ps/√km for ITU-T G.652D standard fiber) higher data rates sets higher requirements for signal quality. In this research comparison between three different modulation formats (traditional on-off keying, differential phase shift keying (DPSK) and polarization
shift keying (PolSK)) is given at different optical fiber PMD levels and data transmission rates. It is found that most significant impact of PMD is to traditional on-off keying modulation format, but the best performance showed DPSK modulated signals
Optical Fiber Nonlinear Coefficient Measurements Using Four-Wave Mixing
No full textOptical fiber (OF) nonlinearity and the length are two the most important parameters that determine the amount of nonlinear phenomena occurrence in the optical waveguide. Therefore when considering specific telecommunications OF nonlinear characteristics it is very important to determine it`s nonlinear coefficient – γ. In this research nonlinear effect four-wave mixing (FWM) was used to determine OF γ. Measurements were performed for highly non-linear fiber (HNLF) and comparison to dispersion shifted fiber is given
Development of Computer Simulation Method and Analysis of Parameters of the Vertical Airstream Generator for Free Flight of Human
No full textIt was discussed the problem of computer modelling of aerodynamic system “generator of a vertical airstream” which consists of the inlet device - the air screw - gasdynamic channel - the straightening device. The developed method of modelling allows to compute and optimize aerodynamic parameters of all elements of the generator taking in to account their geometry. Comparison of calculations with results of natural experiments has confirmed their satisfactory concurrence. On the basis of the analysis of results of computer simulation was executed optimization of geometrical and aerodynamic parameters of vertical airstream generator
The Definition of Placement of Accelerometer in Cyclist’s Jacket
No full textThe prototype of cycling belt has been drawn up with LED stop signals, which are activated by the accelerometer placed in the central back pocket. The results of approbation have shown that the sensor does not provide the proper functioning of signals, due to a high level of riding movements.
Using Motion Capture technology and bicycle exercise equipment, the research of oscillation of anthropometric points on the back has been carried out. The accelerometer should be placed between scapulae to design the cycling jacket
Safe Bicycling - Problems and Solutions
No full textDue to a fast-rising number of cyclists, the safety problems of cyclists become topical. The cyclist’s visibility can remarkably be improved by integrating the light reflective and emissive elements. The aim of the study – to clarify the road participants’ mutual communication problems in the traffic and opportunities solving them with integrating light reflective and emissive elements in cyclist’s suit and also to define the placement of electronic components for the action of designed clothing
Optimal Control of Pantograph-Catenary Systems Using MatLab
No full textThis paper continues research of the pantograph-catenary system started in
previous papers [1,2] and presented in the First International Conference on
Railway Technology [3] . The main purpose of the study is to use the computer to
optimize pantograph-catenary system of a high-speed train by reducing power
consumption when basic parameters of pantograph and catenary (contact
network) are changing in time randomly.
A linear model of pantograph-catenary system is considered where the upper
and lower blocks of pantograph and catenary are modelled using lumped masses,
springs and shock absorbers. Input and output system signals are measured when
the train moves. These signals are processed by parametric identification
algorithms to determine current values of the system matrices. State matrices are
used in the Riccati equation to calculate controller coefficients. Adaptive
controllers provide dynamic stability of the system when its parameters are
changing in time and random external perturbations are present
The Analysis of Noise Level of RGB Image Generated Using SOM
No full textThe article discusses how to generate RGB images
with noise using Kohonen’s self-organizing map (SOM). The
article also describes the adaptation process and structure of
SOM, which can be used to generate RGB images with noise. The
authors of the article evaluate the influence of SOM parameters
(a learning coefficient, adaptation time, effective width) on the
noise level of RGB image generated using SOM. According to
these observations, the authors formulate several
recommendations how to control the noise level by adjusting
SOM parameters
Cloud Computing Evaluation Based on Financial Metrics
No full textInterest in cloud computing is growing, and, as a
result, there is much information about it – both positive and
negative. On the one hand, cloud computing saves money because
it does not require IT infrastructure, servers, and it is very
scalable. On the other hand, it might lead to financial loss due to
security risks, possible data access problems, data privacy
policies, etc. Therefore, cloud computing evaluation based on
financial metrics is proposed in this article. This paper consists of
four major sections. The first section is a literature review of
cloud computing and its types. The next section describes some
common financial metrics such as CBA, ROI and TCO and
describes how they might be applied to evaluate cloud
computing. The third section proposes evaluation strategies, and
the last section contains the evaluation of a series of cloud
computing projects based on chosen evaluation strategies, and
results are verified based on expert opinion