Displaying publications 1 - 20 of 196 in total

  1. Umar Suleiman Dauda, Nik Noordini Nik Abdl Malik, Mazlina Esa, Mohd Fairus Mohd Yusoff, Mohamed Rijal Hamid
    Parameter estimation of complex exponential signals corrupted by additive white
    Gaussian noise (AWGN) is crucial in the study of distributed beamforming in a practical
    scenario. Near zero (0) phase offset are expected at the receiver end which rely on the
    smoothing and correction of the frequency and phase estimates. Neither
    computational complexity nor the processing latency has an effect on the expected
    zero phase offset but the estimation accuracy does. Thus, the maximum likelihood
    estimator (MLE) using Fast Fourier Transform (FFT) approach is being considered for
    cases with none and post processing in locating of the maximum peaks. Details on how
    the phase estimates are arrived at is not always covered in literatures but explained in
    the article. Numerical results obtained showed that global maximum peaks are arrived
    at by employing a fine search with higher values of FFT.
    Matched MeSH terms: Fourier Analysis
  2. Abd Warif NB, Idris MYI, Abdul Wahab AW, Salleh R, Ismail A
    Forensic Sci Int, 2019 Feb;295:83-99.
    PMID: 30576953 DOI: 10.1016/j.forsciint.2018.12.004
    Taking into consideration that the prior CMF detection methods rely on several fixed threshold values in the filtering process, we propose an efficient CMF detection method with an automatic threshold selection, named as CMF-iteMS. The CMF-iteMS recommends a PatchMatch-based CMF detection method that adapts Fourier-Mellin Transform (FMT) as the feature extraction technique while a new automatic threshold selection based on iterative means of regions size (iteMS) procedure is introduced to have flexibility in changing the threshold value for various characteristics (quality, sizes, and attacks) in each input image. To ensure the reliability of the proposed CMF-iteMS, the method is compared with four state-of-the-art CMF detection methods based on Scale Invariant Feature Transform (SIFT), patch matching, multi-scale analysis and symmetry techniques using three available datasets that cover the variety of characteristics in CMF images. The results show that the F-score of the CMF-iteMS outperformed existing CMF detection methods by exceeding an average of 90% F-score values for image-level evaluation and 82% of F-score value for pixel-level evaluation for all datasets in original size. As special attention is given to the image resizing attack, the method is able to maintain the highest performance even if the images in the datasets are resized to 0.25 parameter.
    Matched MeSH terms: Fourier Analysis
  3. Jusoh, M.Z.M., Nur Ain, A.R, Muhammad Wafi Md Nor
    ESTEEM Academic Journal, 2020;16(2):65-74.
    A computational fluid dynamic analysis (CFD) is presented in the study of low Reynolds number fluid flow moving past bluff bodies. The study is focusing on the understanding of the effects of the apex-angles orientation on the flow structure and related occurring force. The apex-angle both facing upstream and downstream were computationally investigated. The simulation results of the cylinder solid are compared with available experimental data to justify the results and the model used. Results obtained in the present work were Strouhal number, drag coefficient, and Fast Fourier Transform (FFT). The study had found that the value of the drag force is increasing directly proportional to the apex angle. In contrast, the value of Strouhal number inversely proportional to the increasing of the apex angle. This was due to the flow over a cylinder creating a vortex shedding in the wake region which influenced the flow separation of fluid. Through the changing on orientation of the apex angle, it was also found that the characteristic linear dimension of the geometry will also be changed, thus affecting the flow pattern.
    Matched MeSH terms: Fourier Analysis
  4. Kazemi M, Bala Krishnan M, Aik Howe T
    Iran J Allergy Asthma Immunol, 2013 Sep;12(3):236-46.
    PMID: 23893807
    In this paper, the method of differentiating asthmatic and non-asthmatic patients using the frequency analysis of capnogram signals is presented. Previously, manual study on capnogram signal has been conducted by several researchers. All past researches showed significant correlation between capnogram signals and asthmatic patients. However all of them are just manual study conducted through the conventional time domain method. In this study, the power spectral density (PSD) of capnogram signals is estimated by using Fast Fourier Transform (FFT) and Autoregressive (AR) modelling. The results show the non-asthmatic capnograms have one component in their PSD estimation, in contrast to asthmatic capnograms that have two components. Furthermore, there is a significant difference between the magnitude of the first component for both asthmatic and non-asthmatic capnograms. The effectiveness and performance of manipulating the characteristics of the first frequency component, mainly its magnitude and bandwidth, to differentiate between asthmatic and non-asthmatic conditions by means of receiver operating characteristic (ROC) curve analysis and radial basis function (RBF) neural network were shown. The output of this network is an integer prognostic index from 1 to 10 (depends on the severity of asthma) with an average good detection rate of 95.65% and an error rate of 4.34%. This developed algorithm is aspired to provide a fast and low-cost diagnostic system to help healthcare professional involved in respiratory care as it would be possible to monitor severity of asthma automatically and instantaneously.
    Matched MeSH terms: Fourier Analysis*
  5. Sambasevam KP, Mohamad S, Sarih NM, Ismail NA
    Int J Mol Sci, 2013;14(2):3671-82.
    PMID: 23434664 DOI: 10.3390/ijms14023671
    A β-cyclodextrin (β-Cyd) inclusion complex containing azomethine as a guest was prepared by kneading method with aliquot addition of ethanol. The product was characterized by Fourier Transform Infrared (FTIR) spectrometer, 1H Nuclear Magnetic Resonance (1H NMR) and Thermogravimetric Analyzer (TGA), which proves the formation of the inclusion complex where the benzyl part of azomethine has been encapsulated by the hydrophobic cavity of β-Cyd. The interaction of β-Cyd and azomethine was also analyzed by means of spectrometry by UV-Vis spectrophotometer to determine the formation constant. The formation constant was calculated by using a modified Benesi-Hildebrand equation at 25 °C. The apparent formation constant obtained was 1.29 × 104 L/mol. Besides that, the stoichiometry ratio was also determined to be 1:1 for the inclusion complex of β-Cyd with azomethine.
    Matched MeSH terms: Fourier Analysis
  6. Samsir SA, Bunawan H, Yen CC, Noor NM
    Data Brief, 2016 Sep;8:1-5.
    PMID: 27257614 DOI: 10.1016/j.dib.2016.04.062
    In this dataset, we distinguish 15 accessions of Garcinia mangostana from Peninsular Malaysia using Fourier transform-infrared spectroscopy coupled with chemometric analysis. We found that the position and intensity of characteristic peaks at 3600-3100 cm(-) (1) in IR spectra allowed discrimination of G. mangostana from different locations. Further principal component analysis (PCA) of all the accessions suggests the two main clusters were formed: samples from Johor, Melaka, and Negeri Sembilan (South) were clustered together in one group while samples from Perak, Kedah, Penang, Selangor, Kelantan, and Terengganu (North and East Coast) were in another clustered group.
    Matched MeSH terms: Fourier Analysis
  7. Gunasekaran D, Bunawan H, Ismail I, Noor NM
    Data Brief, 2018 Aug;19:1423-1427.
    PMID: 30229014 DOI: 10.1016/j.dib.2018.06.025
    In this dataset, we differentiate four different tissues of Cosmos caudatus Kunth (leaves, flowers, stem and root) obtained from UKM Bangi plot, based on Fourier transform-infrared spectroscopy. Different tissues of C. caudatus demonstrated the position and intensity of characteristic peaks at 4000-450 cm-1. Principal component analysis (PCA) shows three main groups were formed. The samples from leaves and flowers were found to be clustered together in one group, while the samples from stems and roots were clustered into two separate groups, respectively. This data provides an insight into the fingerprint identification and distribution of metabolites in the different organs of this species.
    Matched MeSH terms: Fourier Analysis
  8. Leow T, Leong P, Eeu T, Ibrahim Z, Hussin R
    Sains Malaysiana, 2014;43:929-934.
    Study of a series of lead lithium borophosphate glass samples was performed to determine the structural and luminescence properties. The glass samples containing the composition of 20Pb0-xLi20-30B 20 3-(50-x)P 20 5-2TiO 2 (where x = 0, 5, 10, 15, 20) system were prepared using melt-quenching technique. The Pb0-Li20-B 20 3-P20 5-Ti0 2 samples were investigated for structural properties using Fourier transform infrared and photoluminescence spectroscopy for studies of luminescence properties. The results from FTIR showed the presence of trigonal and tetrahedral PO4' PO3, BO4 and B03 groups within the host network structure. The samples exhibit luminescence emission centered at 420, 482 and 496 nm when excited at 300 nm wavelength. The emission peak at 420 nm were assigned to F center emission and charge-transfer transition of Ti4+ ions. The results showed that emission intensity was dependent on lithium contents in Ti-doped lead lithium borophosphate glass composition.
    Matched MeSH terms: Fourier Analysis
  9. Ooi SY, Ishak Ahmad, Mohd Cairul Iqbal Mohd Amin
    Sains Malaysiana, 2015;44:793-799.
    In this research, a novel method was performed to obtain hydrogel with superior thermal stability by incorporation
    of cellulose nanocrystals (CNC) into gelatin based hydrogel. Glutaraldehyde was used as cross-linker due to its high
    chemical reactivity towards NH2
    group on gelatin. Different ratio of gelatin/CNC hydrogel was produced in order to study
    the effects of CNC towards the swelling behaviour and thermal stability of gelatin based hydrogel. The obtained hydrogel
    was subjected to Fourier transform infrared (FTIR) to verify that gelatin had been cross-linked, swelling test with different
    pH for swelling behaviour and thermogravimetric analysis (TGA) for thermal stability. The presence of C=N stretching
    group in the FTIR spectrum for gelatin/CNC hydrogel indicated that the cross-linking reaction between gelatin monomer
    had been successfully carried out. The hydrogel showed impressive pH sensitivity and maximum swelling was obtained
    at pH3. The TGA results clearly showed that the incorporation of CNC into gelatin was able to produce hydrogel with
    higher thermal stability compare to neat gelatin.
    Matched MeSH terms: Fourier Analysis
  10. Maisara Abdul Kadir, Nafisah Mansor, Uwaisulqarni M. Osman
    Sains Malaysiana, 2017;46:725-731.
    A series of monoamide isomers have been successfully synthesised and characterised using combination of common spectroscopic techniques such Fourier Transform Infrared (FT-IR), 1H and 13C Nuclear Magnetic Resonance (NMR) and Ultraviolet-visible (UV-vis). The monoamide compounds namely 6-(3-methyl-pyridin-2-ylcarbamoyl)-pyridine2-carboxylic acid methyl ester (L1), 6-(4-methyl-pyridin-2-ylcarbamoyl)-pyridine-2-carboxylic acid methyl ester (L2), 6-(5-methyl-pyridin-2-ylcarbamoyl)-pyridine-2-carboxylic acid methyl ester (L3) and 6-(6-methyl-pyridin-2ylcarbamoyl)-pyridine-2-carboxylic acid methyl ester (L4) were prepared from reaction between 6-(methoxycarbonyl) pyridine-2-carboxylic acid with 2-amino-N-methylpyridine (where N = 3, 4, 5 and 6) by using acyl chloride reaction. In this present studies, the synthesis and characterization of these compounds are discussed along with the inductive effects contributed by methyl substituted groups at the pyridine ring.
    Matched MeSH terms: Fourier Analysis
  11. Suradi SH, Abdullah KA
    Curr Med Imaging, 2021 Jan 26.
    PMID: 33504312 DOI: 10.2174/1573405617666210127101101
    BACKGROUND: Digital mammograms with appropriate image enhancement techniques will improve breast cancer detection, and thus increase the survival rates. The objectives of this study were to systematically review and compare various image enhancement techniques in digital mammograms for breast cancer detection.

    METHODS: A literature search was conducted with the use of three online databases namely, Web of Science, Scopus, and ScienceDirect. Developed keywords strategy was used to include only the relevant articles. A Population Intervention Comparison Outcomes (PICO) strategy was used to develop the inclusion and exclusion criteria. Image quality was analyzed quantitatively based on peak signal-noise-ratio (PSNR), Mean Squared Error (MSE), Absolute Mean Brightness Error (AMBE), Entropy, and Contrast Improvement Index (CII) values.

    RESULTS: Nine studies with four types of image enhancement techniques were included in this study. Two studies used histogram-based, three studies used frequency-based, one study used fuzzy-based and three studies used filter-based. All studies reported PSNR values whilst only four studies reported MSE, AMBE, Entropy and CII values. Filter-based was the highest PSNR values of 78.93, among other types. For MSE, AMBE, Entropy, and CII values, the highest were frequency-based (7.79), fuzzy-based (93.76), filter-based (7.92), and frequency-based (6.54) respectively.

    CONCLUSION: In summary, image quality for each image enhancement technique is varied, especially for breast cancer detection. In this study, the frequency-based of Fast Discrete Curvelet Transform (FDCT) via the UnequiSpaced Fast Fourier Transform (USFFT) shows the most superior among other image enhancement techniques.

    Matched MeSH terms: Fourier Analysis
  12. Ming NH, Ramesh S, Ramesh K
    Sci Rep, 2016 06 08;6:27630.
    PMID: 27273020 DOI: 10.1038/srep27630
    In this study, dye-sensitized solar cells (DSSCs) has been assembled with poly(1-vinylpyrrolidone-co-vinyl acetate) (P(VP-co-VAc)) gel polymer electrolytes (GPEs) which have been incorporated with binary salt and an ionic liquid. The potential of this combination was studied and reported. The binary salt system GPEs was having ionic conductivity and power conversion efficiency (PCE) that could reach up to 1.90 × 10(-3) S cm(-1) and 5.53%, respectively. Interestingly, upon the addition of the ionic liquid, MPII into the binary salt system the ionic conductivity and PCE had risen steadily up to 4.09 × 10(-3) S cm(-1) and 5.94%, respectively. In order to know more about this phenomenon, the electrochemical impedance studies (EIS) of the GPE samples have been done and reported. Fourier transform infrared studies (FTIR) and thermogravimetric analysis (TGA) have also been studied to understand more on the structural and thermal properties of the GPEs. The Nyquist plot and Bodes plot studies have been done in order to understand the electrochemical properties of the GPE based DSSCs and Tafel polarization studies were done to determine the electrocatalytic activity of the GPE samples.
    Matched MeSH terms: Fourier Analysis
  13. Dadrasnia A, Chuan Wei KS, Shahsavari N, Azirun MS, Ismail S
    Int J Environ Res Public Health, 2015 Dec;12(12):15321-38.
    PMID: 26633454 DOI: 10.3390/ijerph121214985
    The present study investigated the biosorption capacity of live and dead cells of a novel Bacillus strain for chromium. The optimum biosorption condition was evaluated in various analytical parameters, including initial concentration of chromium, pH, and contact time. The Langmuir isotherm model showed an enhanced fit to the equilibrium data. Live and dead biomasses followed the monolayer biosorption of the active surface sites. The maximum biosorption capacity was 20.35 mg/g at 25 °C, with pH 3 and contact time of 50 min. Strain 139SI was an excellent host to the hexavalent chromium. The biosorption kinetics of chromium in the dead and live cells of Bacillus salmalaya (B. salmalaya) 139SI followed the pseudo second-order mechanism. Scanning electron microscopy and fourier transform infrared indicated significant influence of the dead cells on the biosorption of chromium based on cell morphological changes. Approximately 92% and 70% desorption efficiencies were achieved using dead and live cells, respectively. These findings demonstrated the high sorption capacity of dead biomasses of B. salmalaya 139SI in the biosorption process. Thermodynamic evaluation (ΔG⁰, ΔH⁰, and ΔS⁰) indicated that the mechanism of Cr(VI) adsorption is endothermic; that is, chemisorption. Results indicated that chromium accumulation occurred in the cell wall of B. salmalaya 139SI rather than intracellular accumulation.
    Matched MeSH terms: Fourier Analysis
  14. Zabidi A, Khuan LY, Mansor W, Yassin IM, Sahak R
    PMID: 22254916 DOI: 10.1109/IEMBS.2011.6090759
    Hypothyroidism in infants is caused by the insufficient production of hormones by the thyroid gland. Due to stress in the chest cavity as a result of the enlarged liver, their cry signals are unique and can be distinguished from the healthy infant cries. This study investigates the effect of feature selection with Binary Particle Swarm Optimization on the performance of MultiLayer Perceptron classifier in discriminating between the healthy infants and infants with hypothyroidism from their cry signals. The feature extraction process was performed on the Mel Frequency Cepstral coefficients. Performance of the MLP classifier was examined by varying the number of coefficients. It was found that the BPSO enhances the classification accuracy while reducing the computation load of the MLP classifier. The highest classification accuracy of 99.65% was achieved for the MLP classifier, with 36 filter banks, 5 hidden nodes and 11 BPS optimised MFC coefficients.
    Matched MeSH terms: Fourier Analysis
  15. Salimi N, Loh KH, Kaur Dhillon S, Chong VC
    PeerJ, 2016;4:e1664.
    PMID: 26925315 DOI: 10.7717/peerj.1664
    Background. Fish species may be identified based on their unique otolith shape or contour. Several pattern recognition methods have been proposed to classify fish species through morphological features of the otolith contours. However, there has been no fully-automated species identification model with the accuracy higher than 80%. The purpose of the current study is to develop a fully-automated model, based on the otolith contours, to identify the fish species with the high classification accuracy. Methods. Images of the right sagittal otoliths of 14 fish species from three families namely Sciaenidae, Ariidae, and Engraulidae were used to develop the proposed identification model. Short-time Fourier transform (STFT) was used, for the first time in the area of otolith shape analysis, to extract important features of the otolith contours. Discriminant Analysis (DA), as a classification technique, was used to train and test the model based on the extracted features. Results. Performance of the model was demonstrated using species from three families separately, as well as all species combined. Overall classification accuracy of the model was greater than 90% for all cases. In addition, effects of STFT variables on the performance of the identification model were explored in this study. Conclusions. Short-time Fourier transform could determine important features of the otolith outlines. The fully-automated model proposed in this study (STFT-DA) could predict species of an unknown specimen with acceptable identification accuracy. The model codes can be accessed at http://mybiodiversityontologies.um.edu.my/Otolith/ and https://peerj.com/preprints/1517/. The current model has flexibility to be used for more species and families in future studies.
    Matched MeSH terms: Fourier Analysis
  16. Henna Lu, F.S., Tan, P.P
    This aim of this research is to investigate thermal stability of virgin coconut oil, (VCO) which was heated at 190°C upon 40 days storage as compared to extra virgin olive oil (EVOO). The changes in fatty acids composition through (GC), Fourier Transform Infrared (FTIR) spectra, iodine value (IV) and total phenolic content were determined throughout the period of study. Results from GC showed that there was significant changes (P
    Matched MeSH terms: Fourier Analysis
  17. Tajau, R., Wan Yunus, W.M.Z., Mohd Dahlan, K.Z., Mahmood, M.H., Hashim, K., Ismail, M., et al.
    This study demonstrated the utilization of radiation-induced initiator methods for the formation of
    nanoparticles of Acrylated Palm Oil (APO) using aqueous Pluronic F-127 (PF-127) microemulsion
    system. This microemulsion system was subjected to gamma irradiation to form the crosslinked APO
    nanoparticles. Dynamic light scattering (DLS), Fourier Transform Infrared (FTIR) spectroscopy and
    Transmission Electron Microscopy (TEM) were used to characterize the size and the chemical structure
    of the nanoparticles. As a result, the size of the APO nanoparticle was decreased when the irradiation
    dose increased. The decrease in size might be due to the effects of intermolecular crosslinking and
    intramolecular crosslinking reactions of the APO nanoparticles during irradiation process. The size of the
    nanoparticle is in the range of 98 to 200 nanometer (nm) after irradiation using gamma irradiator. This radiation-induced method provides a free initiator
    induced and easy to control process as compared
    to the classical or chemical initiator process. The
    study has shown that radiation-induced initiator
    methods, namely, polymerization and crosslinking
    in the microemulsion, were promising for the
    synthesis of nanoparticles.
    Matched MeSH terms: Fourier Analysis
  18. Nurrulhidayah, A.F., Che Man, Y.B., Shuhaimi, M., Rohman, A., Khatib, A., Amin, I.
    The use of Fourier transform infrared (FTIR) spectroscopy coupled with chemometric techniques to differentiate butter from beef fat (BF) was investigated. The spectral bands associated with butter, BF, and their mixtures were scanned, interpreted, and identified by relating them to those spectroscopically representative to pure butter and BF. For quantitative analysis, partial least square (PLS) regression was used to develop a calibration model at the selected fingerprint regions of 1500-1000 cm-1, with the values of coefficient of determination (R2) and root mean square error of calibration (RMSEC) are 0.999 and 0.89% (v/v), respectively. The PLS calibration model was subsequently used for the prediction of independent samples containing butter in the binary mixtures with BF. Using 6 principal components, root mean square error of prediction (RMSEP) is 2.42% (v/v). These results proved that FTIR spectroscopy in combination with multivariate calibration can be used for the detection and quantification of BF in butter formulation for authentication use.
    Matched MeSH terms: Fourier Analysis
  19. Muhamad Faridz Osman, Karimah Kassim
    The coordination complexes of Co(II) and Zn(II) with Schiff bases derived from ophenylenediamine and substituted 2-hydroxybenzaldehyde were prepared. All compounds were characterized by Fourier transform infrared (FTIR) spectroscopy and Nuclear magnetic resonance (NMR) spectroscopy elemental analyzers. They were analyzed using impedance spectroscopy in the frequency range of 100Hz - 1MHz. L1 and L2 showed higher conductivity compared to their metal
    complexes, which had values of 1.37 x 10-7 and 6.13 x 10-8S/cm respectively.
    Matched MeSH terms: Fourier Analysis
  20. Wong JY, Chu C, Chong VC, Dhillon SK, Loh KH
    J Fish Biol, 2016 Aug;89(2):1324-44.
    PMID: 27364089 DOI: 10.1111/jfb.13039
    Combined multiple 2D views (proximal, anterior and ventral aspects) of the sagittal otolith are proposed here as a method to capture shape information for fish classification. Classification performance of single view compared with combined 2D views show improved classification accuracy of the latter, for nine species of Sciaenidae. The effects of shape description methods (shape indices, Procrustes analysis and elliptical Fourier analysis) on classification performance were evaluated. Procrustes analysis and elliptical Fourier analysis perform better than shape indices when single view is considered, but all perform equally well with combined views. A generic content-based image retrieval (CBIR) system that ranks dissimilarity (Procrustes distance) of otolith images was built to search query images without the need for detailed information of side (left or right), aspect (proximal or distal) and direction (positive or negative) of the otolith. Methods for the development of this automated classification system are discussed.
    Matched MeSH terms: Fourier Analysis
Contact Us

Please provide feedback to Administrator (tengcl@gmail.com)

External Links