1,721,289 research outputs found
Reduced Fractional Modeling of 3D Video Streams: the FERMA Approach
Full text linkMultimedia streaming of three-dimensional (3D) stereoscopic videos over last-generation networks subject to bandwidth limitations is an open problem. The development and spread of communication networks and devices that accept 3D videos is not supported by proper scheduling strategies. Namely the high variability of streams should be considered to reduce effects of network delays, packet losses, shortage of bandwidth resources, and shared use by multiple clients. Then, it is important to improve the characterization of 3D videos for more effective streaming. To this aim, this paper proposes a fractional exponential reduction moments approach based on the statistics of the so-called fractional moments. Each random sequence of frames in 3D videos can be analyzed and reduced to a finite set of parameters, that allow fitting to the sequence by exponential functions and then a characterization and classification of the video by a sort of fingerprint. The method does not depend on the format and the encoding technique of the video. Finally, the approach will allow comparing real streams and numerical data output from fractional dynamical models by means of the reduced parameters. Statistical proximity between time series and a fractional model or between different models simplifies formalization and classification of fractional models
Reduced Fractal Model for Quantitative Analysis of Averaged Micromotions in Mesoscale: Characterization of Blow-Like Signals
No full textIt has been shown that many micromotions in the mesoscale region are averaged in
accordance with their self-similar (geometrical/dynamical) structure. This distinctive feature
helps to reduce a wide set of different micromotions describing relaxation/exchange
processes to an averaged collective motion, expressed mathematically in a rather general
form. This reduction opens new perspectives in description of different blow-like signals
(BLS) in many complex systems. The main characteristic of these signals is a finite duration
also when the generalized reduced function is used for their quantitative fitting. As an
example, we describe quantitatively available signals that are generated by bronchial asthmatic
people, songs by queen bees, and car engine valves operating in the idling regime.
We develop a special treatment procedure based on the eigen-coordinates (ECs) method
that allows to justify the generalized reduced fractal model (RFM) for description of BLS
that can propagate in different complex systems. The obtained describing function is based
on the self-similar properties of the different considered micromotions. This kind of
cooperative model is proposed here for the first time. In spite of the fact that the nature
of the dynamic processes that take place in fractal structure on a mesoscale level is not well
understood, the parameters of the RFM fitting function can be used for construction of
calibration curves, affected by various external/random factors. Then, the calculated set
of the fitting parameters of these calibration curves can characterize BLS of different
complex systems affected by those factors. Though the method to construct and analyze
the calibration curves goes beyond the scope of this paper, this result could benefit future
studies that will employ the developed reduced models in diagnosis, prevention, and
control of unpredicted and undesired phenomena of some engineering applications that
possibly exhibit such BLS
"Universal" Fitting Function for Complex Systems: Case of the Short Samplings
No full textThe authors suggest an effective scheme for quantitative description of complex systems, when the number of measurements is relatively small. It has a great importance for quantitative description of expensive and rare experiments when the volume of the sampling is small. They proposed a simple theory that is based on the previous results associated with conception of the intermediate model (IM). The previous results can be generalized and applicable for description of complex systems with short samplings when the influence of the uncontrollable factors becomes significant. As an example, we consider the description of acoustic signals recorded from turbine bearings. It can be proved that the real signals have self-similar (fractal) properties. It helps to compress the length of the initial files (number of data points N = 44100) at least in 88 times and reduced essentially the number of the fitting parameters. The obtained results can be used for diagnosis of different defects during the process of technical exploitation. Each failure has own acoustic “picture” i.e. the amplitude-frequency response (AFR) expressed in terms of the generalized Prony spectrum (GPS). This AFR can be used as a “specific” fingerprint for identification of the unexpected failure and preventing a possible breakdown
Statistics of Fractional Moments Applied to 3D Video Streams
No full textThe interest in processing three-dimensional (3D) videos is ever increasing because of the exponential growth of sophisticated devices supporting 3D streams. However, transmitting compressed 3D videos on channels with relatively limited bandwidth resources is a challenging research problem, because of the high variability of 3D streams. A stable and robust characterization of the statistical properties of 3D videos could be very useful for several applications (bandwidth management and control by effective schedulers/controllers, call admission control schemes, etc.). This work proposes a straightforward characterization method, based on the statistics of fractional moments. The properties of long sequences of 3D videos are reduced to a very small set of fitting parameters, constituting the video “fingerprint”. The method is applied to a set of videos, with different compression degrees. Moreover, possible similarities among different fingerprints are investigated for an effective 3D video classificatio
Biosynthesis and characterization of a novel, biocompatible medium chain length polyhydroxyalkanoate by Pseudomonas mendocina CH50 using coconut oil as the carbon source
No full textAbstract: This study validated the utilization of triacylglycerides (TAGs) by Pseudomonas mendocina CH50, a wild type strain, resulting in the production of novel mcl-PHAs with unique physical properties. A PHA yield of 58% dcw was obtained using 20 g/L of coconut oil. Chemical and structural characterisation confirmed that the mcl-PHA produced was a terpolymer comprising of three different repeating monomer units, 3-hydroxyoctanoate, 3-hydroxydecanoate and 3-hydroxydodecanoate or P(3HO-3HD-3HDD). Bearing in mind the potential of P(3HO-3HD-3HDD) in biomedical research, especially in neural tissue engineering, in vitro biocompatibility studies were carried out using NG108-15 (neuronal) cells. Cell viability data confirmed that P(3HO-3HD-3HDD) supported the attachment and proliferation of NG108-15 and was therefore confirmed to be biocompatible in nature and suitable for neural regeneration. [Figure not available: see fulltext.]
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Manufacture of cellulose fibre reinforced composites
No full textHighly aligned, discontinuous cellulose and cellulose/carbon fibre-reinforced composites have been produced using the High Performance Discontinuous Fibre (HiPerDiF) technology. With the addition of carbon fibre, the mechanical performance of cellulose fibre-reinforced composites changes from two-phase ductile to linear stiff. With constant fibre volume fraction (Vf), as the cellulose/carbon volume ratio decreases from 100:0 to 50:50, less composite defects appear. Correspondingly, their composite stiffness and strength increase (7 GPa, 146 MPa; 32 GPa, 412 MPa), while failure strain decrease (from 6.2% to 1.3%). To optimise the manufacturing route of cellulose fibre-reinforced composites, cellulose composites with three different fibre volume fractions have also been manufactured. The cellulose composites with an estimated Vf 71% possess the best mechanical properties (8.54 GPa, 143.23 MPa, 3.03%) and the least composite defects
"Universal" Fitting Function for Quantitative Description of Quasi-Reproducible Measurements
No full textIn this paper the authors are trying to justify the following statement: is there a general platform (it is defined as an intermediate model (IM)) for description of a wide class of quasi-reproducible (QR) experiments? Under QR experiments we understand the set of measurements when during a measurement cycle they can be varied significantly under the influence of uncontrollable factors. If this general platform exists then it facilities the analysis of experiments associated with properties of complex systems, when the "best-fit function" that follows from the microscopic model is absent. This platform will bring a certain profit for a competitive/alternative theory. If the fitting function obtained from the theory looks very complicated then it can be expressed in terms of the IM and the parameters of this IM are expressed in terms of the generalized Prony spectrum. The physical meaning of the Fourier transform that used as the fitting function is explained also. It corresponds to an "ideal experiment" when all measurements during the experimental cycle are fully identical to each other. The new formulae for elimination of the apparatus functions are suggested. They help to evaluate the influence of uncontrollable factors and at certain conditions reduce the measured data to an "ideal experiment". As a nontrivial example we consider the fit of the single heartbeat (HB) recorded from anonymous persons. We took the ECG data from the reliable Internet resource PhysioNet Bank (http://physionet.org/cgi-bin/atm/ATM). The obtained results of its nontrivial application demonstrate its effectiveness in quantitative description of the ECG data in the frame of the suggested theory. We do hope that the quantitative description of the single heartbeat will find an application in the modern cardiology
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