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4. Unwrapping the phase portrait features of adventitious crackle for auscultation and classification: A machine learning approachMohanachandran Nair Sindhu Swapna, 2021, izvirni znanstveni članek Opis: The paper delves into the plausibility of applying fractal, spectral, and nonlinear time series analyses for lung auscultation. The thirty-five sound signals of bronchial (BB) and pulmonary crackle (PC) analysed by fast Fourier transform and wavelet not only give the details of number, nature, and time of occurrence of the frequency components but also throw light onto the embedded air flow during breathing. Fractal dimension, phase portrait, and sample entropy help in divulging the greater randomness, antipersistent nature, and complexity of airflow dynamics in BB than PC. The potential of principal component analysis through the spectral feature extraction categorises BB, fine crackles, and coarse crackles. The phase portrait feature-based supervised classification proves to be better compared to the unsupervised machine learning technique. The present work elucidates phase portrait features as a better choice of classification, as it takes into consideration the temporal correlation between the data points of the time series signal, and thereby suggesting a novel surrogate method for the diagnosis in pulmonology. The study suggests the possible application of the techniques in the auscultation of coronavirus disease 2019 seriously affecting the respiratory system. Ključne besede: Auscultation, Biomedical signal processing, Fractals, Machine learning, Phase portrait, Pulmonary crackle. Objavljeno v RUNG: 30.06.2022; Ogledov: 1729; Prenosov: 0 Gradivo ima več datotek! Več... |
5. Fractal and spectroscopic analysis of soot from internal combustion enginesMohanachandran Nair Sindhu Swapna, SARITHA DEVI H V, RAJ VIMAL, Sankararaman S, 2018, izvirni znanstveni članek Opis: Today diesel engines are used worldwide for various applications and very importantly in transportation. Hydrocarbons are the most widespread precursors among carbon sources employed in the production of carbon nanotubes (CNTs). The aging of internal combustion engine is an important parameter in deciding the carbon emission and particulate matter due to incomplete combustion of fuel. In the present work, an attempt has been made for the effective utilization of the aged engines for potential applicationapplications in fuel cells and nanoelectronics. To analyze the impact of aging, the particulate matter rich in carbon content areis collected from diesel engines of different ages. The soot with CNTs is purified by the liquid phase oxidation method and analyzed by Field Emission Scanning Electron Microscopy, High-Resolution Transmission Electron Microscopy, Energy Dispersive Spectroscopy, UV-Visible spectroscopy, Raman spectroscopy and Thermogravimetric analysis. The SEM image contains self-similar patterns probing fractal analysis. The fractal dimensions of the samples are determined by the box counting method. We could find a greater amount of single-walled carbon nanotubes (SWCNTs) in the particulate matter emitted by aged diesel engines and thereby giving information about the combustion efficiency of the engine. The SWCNT rich sample finds a wide range of applications in nanoelectronics and thereby pointing a potential use of these aged engines. Ključne besede: Fractals, internal combustion engine, efficiency, soot, carbon nanoparticle Objavljeno v RUNG: 30.06.2022; Ogledov: 2092; Prenosov: 0 Gradivo ima več datotek! Več... |
6. Fractal analysis - a surrogate technique for material characterizationMohanachandran Nair Sindhu Swapna, Sankararaman S, 2017, izvirni znanstveni članek Opis: Fractal analysis has emerged as a potential analytical tool in almost all branches of science and technology. The paper is the first report of using fractal dimension as a surrogate technique for estimating particle size. A regression equation is set connecting the soot particle size and fractal dimension, after investigating the Field Emission Scanning Electron Microscopic (FESEM) images of carbonaceous soot from five different sources. Since the fractal dimension is an invariant property under the scale transformation, an ordinary photograph of the soot should
also yield the same fractal dimension. This enables one to determine the average size of the soot particles, using the regression equation, by calculating the fractal dimension from the photograph. Hence, instead of frequent measurement of average particle size from FESEM, this technique of estimating the particle size from the fractal dimension of the soot photograph, is found to be a potentially cost-effective and non-contact method. Ključne besede: fractals, FESEM, carbon nanoparticles, particle size, box-counting Objavljeno v RUNG: 30.06.2022; Ogledov: 2047; Prenosov: 0 Gradivo ima več datotek! Več... |
7. Fractal and fingerprint analysis through phase embedded diffraction patternMohanachandran Nair Sindhu Swapna, 2017, izvirni znanstveni članek Opis: Fingerprint recognition is the most popular biometric identification method currently employed
in security applications. Though there are several optical methods for fingerprint analysis based on
intensity recording, phase recording alone can give the precise result. Interference and diffraction
phenomenon are capable of recording phase variations. In the present method diffraction patterns
corresponding to the fingerprints are generated and the spacing between the ridges is calculated. The
spacing between ridges is found to be in agreement with the value measured using the software ImageJ.
The fingerprint impressions of more than thirty-five persons are recorded and analyzed using the
statistical tools in Matlab.The fingerprints are also subjected to fractal analysis. The program could
successfully identify a fingerprint from the database. The present work is the first report of fingerprint
analysis from diffraction pattern Ključne besede: Diffraction, Skew, Kurtosis, Fractals Objavljeno v RUNG: 30.06.2022; Ogledov: 1670; Prenosov: 0 Gradivo ima več datotek! Več... |
8. Time series and fractal analyses of wheezing : a novel approachMohanachandran Nair Sindhu Swapna, Ammini Renjini, Vimal Raj, S. Sreejyothi, Sankaranarayana Iyer Sankararaman, 2020, izvirni znanstveni članek Opis: Since the outbreak of the pandemic Coronavirus Disease 2019, the world is in search of novel non-invasive methods for safer
and early detection of lung diseases. The pulmonary pathological symptoms refected through the lung sound opens a possibility of detection through auscultation and of employing spectral, fractal, nonlinear time series and principal component
analyses. Thirty-fve signals of vesicular and expiratory wheezing breath sound, subjected to spectral analyses shows a clear
distinction in terms of time duration, intensity, and the number of frequency components. An investigation of the dynamics
of air molecules during respiration using phase portrait, Lyapunov exponent, sample entropy, fractal dimension, and Hurst
exponent helps in understanding the degree of complexity arising due to the presence of mucus secretions and constrictions
in the respiratory airways. The feature extraction of the power spectral density data and the application of principal component analysis helps in distinguishing vesicular and expiratory wheezing and thereby, giving a ray of hope in accomplishing
an early detection of pulmonary diseases through sound signal analysis. Ključne besede: auscultation, wheeze, fractals, nonlinear time series analysis, sample entropy Objavljeno v RUNG: 30.06.2022; Ogledov: 2124; Prenosov: 0 Gradivo ima več datotek! Več... |
9. Thermal Lensing of Multi-Walled Carbon Nanotube Solutions as Heat-Transfer NanofluidsMohanachandran Nair Sindhu Swapna, RAJ VIMAL, CABRERA HUMBERTO, SANKARARAMAN SANKARANARAYANA IYER, 2021, izvirni znanstveni članek Opis: This paper unwraps nanofluids’ particle dynamics with
multi-walled carbon nanotubes (MWCNTs) in base fluids such as
acetone, water, and ethylene glycol. Having confirmed the
morphology and structure of the MWCNTs by field emission
scanning electron microscopy, X-ray diffraction, and Raman
spectroscopic analyses, the nanofluids are prepared in three different concentrations. The nonzero absorbance at the laser wavelength, revealed through the UV−visible spectrum, makes the thermal diffusivity study of the sample by the sensitive nondestructive single beam thermal lens (TL) technique possible. The TL signal analysis by time series and fractal techniques divulges the complex particle dynamics, through phase portrait, sample entropy, fractal dimension, and Hurst exponent. The study unveils the effect of the amount of nanoparticles and the viscosity of the medium on thermal diffusivity and particle dynamics. The observed inverse relation between thermal diffusivity and viscosity is in good agreement with the
Sankar−Swapna model. The complexity of particle dynamics in MWCNT nanofluids reflected through sample entropy, and fractal
dimension shows an inverse relation to the base fluid’s viscosity. This paper investigates the role of viscosity of the base fluid on particle dynamics and thermal diffusivity of the nanofluid to explore its applicability in various thermal systems, thereby suggesting a method to tune the sample entropy through proper selection of base fluid. Ključne besede: MWCNT, thermal lens, fractals, nonlinear time series, phase portrait, sample entropy Objavljeno v RUNG: 28.06.2022; Ogledov: 2331; Prenosov: 0 Gradivo ima več datotek! Več... |
10. HAS EVOLUTION BEEN INTERRUPTED IN THE AFRICAN OIKOS? : MERGING THE SELF-ORGANIZATION ACTIVITY APPROACH USING AFRICAN FRACTAL SPATIAL PATTERNS WITH TANGIBLE AND INTANGIBLE VALUES. YORUBA CITIES AS A CASE STUDYTokunbo Laotan-Brown, 2019, doktorska disertacija Opis: In essence, a qualitative study revealing what the inhabitants reflect as a deep and personal relationship with and within the region, which contributes significantly to their sense of emotional security and self identity. This includes a strong conservation-orientated attitude with regard to the natural rural character of a clan, tribe or unbounded region using linguistic families, especially in the inner core. It acknowledges the journey though time of the dwellers, changes in requirements in a natural way. The principle behind this thesis is to identify the regional, cultural and environmental demands of where and how a fractal spatial function can be observed as well as how a community can be organised to maintain and preserve its culture in a natural way.
Thus, responding to specific characteristics of the local environment and climatic conditions. This lifelong interaction between the cognitive and physical realms has existed overtime. During the evolution of values inhabitants adapted form and materials to the conditions of nature; working with natural forms and climatic cycles rather than considering forces as obstacles to overcome has hermeneutic and practical values; used by intentional makers. The cultural identity in the inhabitant made the home, and then the process of home-making ‘made’ the inhabitant; a reciprocal reward. This will include their connection to the culture, region and environment while proposing a self-organizational solution. The future of conserving African tangible and intangible values, need to take lessons from the past into the future through present resolutions while documenting what maybe an interrupted progression.
To achieve the above, I modified an approach using cultural fractal organizational approach as a basis for defining; 1) The structure of research framework
using computer simulations and thus establishing linkages between space, region and
communal activities. 2) Using African linguistic families (Niger-Congo: Yoruba), as a
distinct way of documenting within the context of co-existing social and discursive practices.
3) By generating a background in ethnographic and sensory archaeological data on Yoruba
regional cities, focusing on the fractal structure of settlements in relation to the social activities that take place in and around them. Ključne besede: Fractals, Self Similarity, Conservation, Self Organizational Approach, Cultural Heritage, Spatial Patterns, IFA, Oikos, Cultural Landscapes, Yoruba Cities, Circularity. Objavljeno v RUNG: 18.01.2019; Ogledov: 5038; Prenosov: 183 Celotno besedilo (24,92 MB) |