Various Levels Of Decomposition Research Articles

An efficient wavelet thresholding strategy and robust shrinkage approach for de‐noising ECG signal

AbstractThis paper introduces an efficient wavelet thresholding strategy and robust shrinkage approach (WTS) for de‐noising the ECG signals. The optimal mother wavelet for de‐noising the ECG signal is automatically selected based on cross‐correlation and energy‐to‐entropy indices. A dynamic threshold is applied to various levels of decomposition to eliminate different types of noise. A shrinkage approach is suggested to attain seamless on–off transitions. The achievement of the WTS is compared with the state of the art reported in the literature using 180 real ECG signals collected from 60 volunteers. The ECG signals were recorded using three standard ECG machines without applying the filtering option to provide a diverse range of noisy ECG signals. The de‐noising outcomes show that the presented WTS can automatically select the optimal mother wavelet for the particular ECG signal, and it is superior to other techniques in terms of the average predicted signal‐to‐noise ratio (), the average predicted root‐mean‐square error (), and the average execution time (AET).

Preservation of Terrestrial Microorganisms and Organics Within Alteration Products of Chondritic Meteorites from the Nullarbor Plain, Australia.

Meteorites that fall to Earth quickly become contaminated with terrestrial microorganisms. These meteorites are out of chemical equilibrium in the environments where they fall, and equilibration promotes formation of low-temperature alteration minerals that can entomb contaminant microorganisms and thus preserve them as microfossils. Given the well-understood chemistry of meteorites and their recent discovery on Mars by rovers, a similarly weathered meteorite on Mars could preserve organic and fossil evidence of a putative past biosphere at the martian surface. Here, we used several techniques to assess the potential of alteration minerals to preserve microfossils and biogenic organics in terrestrially weathered ordinary chondrites from the Nullarbor Plain, Australia. We used acid etching of ordinary chondrites to reveal entombed fungal hyphae, modern biofilms, and diatoms within alteration minerals. We employed synchrotron X-ray fluorescence microscopy of alteration mineral veins to map the distribution of redox-sensitive elements of relevance to chemolithotrophic organisms, such as Mn-cycling bacteria. We assessed the biogenicity of fungal hyphae within alteration veins using a combination of Fourier-transform infrared spectroscopy and pyrolysis gas chromatography-mass spectrometry, which showed that alteration minerals sequester and preserve organic molecules at various levels of decomposition. Our combined analyses results show that fossil microorganisms and the organic molecules they produce are preserved within calcite-gypsum admixtures in meteorites. Furthermore, the distributions of redox-sensitive elements (e.g., Mn) within alteration minerals are localized, which qualitatively suggests that climatically or microbially facilitated element mobilization occurred during the meteorite's residency on Earth. If returned as part of a sample suite from the martian surface, ordinary chondrites could preserve similar, recognizable evidence of putative past life and/or environmental change.

Encryption Based Image Watermarking Algorithm in 2DWT-DCT Domains.

This paper proposes an encryption-based image watermarking scheme using a combination of second-level discrete wavelet transform (2DWT) and discrete cosine transform (DCT) with an auto extraction feature. The 2DWT has been selected based on the analysis of the trade-off between imperceptibility of the watermark and embedding capacity at various levels of decomposition. DCT operation is applied to the selected area to gather the image coefficients into a single vector using a zig-zig operation. We have utilized the same random bit sequence as the watermark and seed for the embedding zone coefficient. The quality of the reconstructed image was measured according to bit correction rate, peak signal-to-noise ratio (PSNR), and similarity index. Experimental results demonstrated that the proposed scheme is highly robust under different types of image-processing attacks. Several image attacks, e.g., JPEG compression, filtering, noise addition, cropping, sharpening, and bit-plane removal, were examined on watermarked images, and the results of our proposed method outstripped existing methods, especially in terms of the bit correction ratio (100%), which is a measure of bit restoration. The results were also highly satisfactory in terms of the quality of the reconstructed image, which demonstrated high imperceptibility in terms of peak signal-to-noise ratio (PSNR ≥ 40 dB) and structural similarity (SSIM ≥ 0.9) under different image attacks.

Formalized description of the elements of semiconductor electricity converters at different decomposition levels

The article describes the principles of mathematical description of the elements of semiconductor electricity converters on the example of an induction motor frequency control system to determine its component and structural composition, as well as analyzing the processes of logical-dynamic information conversion in the interaction of all subsystems of the microprocessor control system. The disadvantages and limitations of the formal methods used to describe processes in control systems are shown. The rules for describing functional structures, such as a rectifier, a passive filter, an inverter, an induction motor, a microcontroller, are defined at various levels of decomposition of the semiconductor electric power converter and its control system. A structural-functional model of a microprocessor control system of induction motor has been developed. The use of proposed functional model allows to define relations and types of connections between control and visualization subsystems, as well as describing the functionality of elements of individual subsystems and signal conversion algorithms. The advantage of the approach proposed in the article is the possibility of using different levels of decomposition for the formalized presentation of subsystems and elements of semiconductor electric power control systems, including frequency control systems for induction motors, which allows to highlight the most important aspects of the description at various stages of system design and analysis. The explicit designations of the elements of the model and the signal conversion elements remain transparent to the developer, and contain information about the purpose of the system elements, the requirements for interaction with other signal transformation subsystems, and their functionality. The use of the proposed approach allows the formation of mathematical models of semiconductor electricity converters and their control systems with enhanced information content, allows to analyze systems by multi-level decomposition to create an idea of its basic properties, to assess the quality of its structure and elements from the perspective of a common systems approach.

On the Thermal Stability of Partially Decomposed Ammonium Perchlorate

AbstractThe response of propellants and explosives to thermal stimuli is an important aspect of their behavior, especially for their safe storage and handling. In the case of ammonium perchlorate (AP), the principal oxidizer used in solid composite propellants, exposure to elevated temperatures causes various levels of decomposition and morphological changes. These changes occur in both neat AP particles and AP based propellants. The hazards associated with thermally damaged, or partially decomposed AP are investigated. It is found that AP is more thermally stable after partial low temperature decomposition. Also, it is found that the extent of decomposition of the AP particles is strongly influenced by prior thermal damage. This dependency is attributed to the exhaustion of nucleation sites on certain crystal planes. Specific surface area measurements of the thermally damaged particles show that the particles recrystallize before they can decompose to a further extent in low temperature decomposition. The behavior of partially decomposed AP in the presence of a propellant binder is also examined.

Nonlinear and adaptive undecimated hierarchical multiresolution analysis for real valued discrete time signals via empirical mode decomposition approach

Hierarchical multiresolution analysis is an important tool for the analysis of signals. Since this multiresolution representation provides a pyramid like framework for representing signals, it can extract signal information effectively via levels by levels. On the other hand, a signal can be nonlinearly and adaptively represented as a sum of intrinsic mode functions (IMFs) via the empirical mode decomposition (EMD) algorithm. Nevertheless, as the IMFs are obtained only when the EMD algorithm converges, no further iterative sifting process will be performed directly when the EMD algorithm is applied to an IMF. As a result, the same IMF will be resulted and further level decompositions of the IMFs cannot be obtained directly by the EMD algorithm. In other words, the hierarchical multiresolution analysis cannot be performed via the EMD algorithm directly. This paper is to address this issue by performing a nonlinear and adaptive hierarchical multiresolution analysis based on the EMD algorithm via a frequency domain approach. In the beginning, an IMF is expressed in the frequency domain by applying discrete Fourier transform (DFT) to it. Next, zeros are inserted to the DFT sequence and a conjugate symmetric zero padded DFT sequence is obtained. Then, inverse discrete Fourier transform (IDFT) is applied to the zero padded DFT sequence and a new signal expressed in the time domain is obtained. Actually, the next level IMFs can be obtained by applying the EMD algorithm to this signal. However, the lengths of these next level IMFs are increased. To reduce these lengths, first DFT is applied to each next level IMF. Second, the DFT coefficients of each next level IMF at the positions where the zeros are inserted before are removed. Finally, by applying IDFT to the shorten DFT sequence of each next level IMF, the final set of next level IMFs are obtained. It is shown in this paper that the original IMF can be perfectly reconstructed. Moreover, computer numerical simulation results show that our proposed method can reach a component with less number of levels of decomposition compared to that of the conventional linear and nonadaptive wavelets and filter bank approaches. Also, as no filter is involved in our proposed method, there is no spectral leakage in various levels of decomposition introduced by our proposed method. Whereas there could be some significant leakage components in the various levels of decomposition introduced by the wavelets and filter bank approaches.

Query by Image Content using Color-Texture Features Extracted from Haar Wavelet Pyramid

The paper presents the Wavelet Pyramid based image retrieval techniques [1] using Haar transform. Here content based image retrieval (CBIR) is done using the image feature set extracted from Haar Wavelets applied on the image at various levels of decomposition. Here the database image features are extracted by applying Haar Wavelets on gray plane (average of red, green and blue) and color planes (red, green and blue components). The techniques Gray-Haar Wavelets and Color-Haar Wavelets are tested on image database having 11 categories with total 1000 images. Total 55 queries are fired on the database. The results show that precision and recall of Haar Wavelets are better than complete Haar transform based CBIR, which proves that Haar Wavelets gives better discrimination capability in image retrieval at higher query execution speed, per higher level Haar Wavelets. Color-Haar Wavelets based CBIR have greater precision and recall than Gray-Haar Wavelets based CBIR. The Haar Wavelets level-5 outperforms other Haar Wavelets, because the higher level Haar Wavelets are giving very coarse color-texture features while the lower level are representing very fine color-texture features which are less useful to differentiate the images in image retrieval.

Performance Comparison of Image Retrieval Techniques using Wavelet Pyramids of Walsh, Haar and Kekre Transforms

The paper presents performance comparison of Wavelet Pyramid based image retrieval techniques using Walsh, Haar and newly introduced Kekre wavelet transforms. Here content based image retrieval (CBIR) is done using the image feature set extracted from Wavelets applied on the image at various levels of decomposition. Here the image features are extracted by applying Wavelets on gray plane (average of red, green and blue) and color planes (red, green and blue components). The techniques Gray-Wavelets and Color-Wavelets are tested on image database having 11 categories with total 1000 images. Total 55 queries are fired on the database. The results show that precision and recall of Wavelets are better than complete transform based CBIR using Walsh and Haar transform, which proves that Wavelets give better discrimination capability in image retrieval at faster query execution speed. The Walsh and Haar Wavelets level-5 outperforms other Wavelets, because the higher level Wavelets are giving coarse color-texture features while the lower level are representing fine color-texture features which are less useful to differentiate the images in image retrieval. ColorWavelets based CBIR have greater precision and recall than Gray-Wavelets based CBIR.

Wool-waste as organic nutrient source for container-grown plants

A container experiment was conducted to test the hypothesis that uncomposted wool wastes could be used as nutrient source and growth medium constituent for container-grown plants. The treatments were: (1) rate of wool-waste application (0 or unamended control, 20, 40, 80, and 120 g of wool per 8-in. pot), (2) growth medium constituents [(2.1) wool plus perlite, (2.2) wool plus peat, and (2.3) wool plus peat plus perlite], and (3) plant species (basil and Swiss chard). A single addition of 20, 40, 80, or 120 g of wool-waste to Swiss chard (Beta vulgaris L.) and basil (Ocimum basilicum L.) in pots with growth medium provided four harvests of Swiss chard and five harvests of basil. Total basil yield from the five harvests was 1.6-5 times greater than the total yield from the unamended control, while total Swiss chard yield from the four harvests was 2-5 times greater relative to the respective unamended control. The addition of wool-waste to the growth medium increased Swiss chard and basil tissue N, and NO(3)-N and NH(4)-N in growth medium relative to the unamended control. Scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) microanalysis of wool fibers sampled at the end of the experiments indicated various levels of decomposition, with some fibers retaining their original surface structure. Furthermore, most of the wool fibers' surfaces contained significant concentrations of S and much less N, P, or K. SEM/EDX revealed that some plant roots grow directly on wool-waste fibers suggesting either (1) root directional growth towards sites with greater nutrient concentration and/or (2) a possible role for roots or root exudates in wool decomposition. Results from this study suggest that uncomposted wool wastes can be used as soil amendment, growth medium constituent, and nutrient source for container-grown plants.

Computer aided fixture design: Using information intensive function models in the development of automated fixture design systems

In this paper, the development of an Information Intensive Function Model (IIFM) of fixture design activities is discussed. This function model was developed using the IDEF-0 (Integrated Definition) methodology and was built primarily after interacting with expert fixture designers. In addition, knowledge from fixture design, tool design, and metalcutting handbooks and from journal papers was used to lend a holistic flavor to the developed IDEF-0 model. An IDEF-0 modeling software tool, AIO Win®, was used to build this model at various levels of decomposition. This paper also discusses the importance of IIFMs in the current and future design of Computer Aided Fixture Design (CAFD) systems.

Stability of solid waste sea fills: shear strength determination and sensitivity analysis

Little is known about the geotechnical properties of waste materials, either in their initial state or after various levels of decomposition. Such information is critical when assessing the stability of waste fills during placement, and at the time of closure and rehabilitation. Recent efforts to address these particular concerns remain in developmental stages, and practical problems persist with regards to in‐situ or laboratory scale testing. In addition, the complexity of the problems is increased due to the variability in composition, placement conditions and levels of decay of the various constituents of the waste fills. This paper describes laboratory experiments that were conducted to establish relevant shear strength parameters for municipal solid waste. The shear strength testing was accomplished by using a large direct shear apparatus specifically designed and developed for the purpose. Results from the laboratory‐testing program are then applied in conducting geotechnical stability analyses at a major sea fill along the Mediterranean shore. A parametric sensitivity analysis affecting stability is also presented.

The wavelet transform: A new preprocessing method for peak recognition of infrared spectra

The wavelet transform, also called wavelet decomposition, recently introduced into the applied sciences and available as software packages, is a powerful method for smoothing experimental data. The wavelet transform is a mathematical transform for hierarchically decomposing functions. It leads to a description of a function, including discrete data vectors or matrices, in terms of a coarse overall shape and details of a graded sequence. This decomposition is the basis for noise reduction. At the various levels of decomposition the coarse coefficients are due to the characteristic signals and part of the details may be interpreted as noise. The method will be discussed on examples of peak recognition in infrared spectroscopy. We will show that some of the wavelet bases lead to a very good compromise between signal/noise ratio enhancement and preservation of the real data structures. Subsequently it enables a Teak ‘Picker’ to find the local maxima of the curve corresponding to real data structures.