Conversion Matrices Research Articles

3DVar sectoral emission inversion based on source apportionment and machine learning

Air quality models are increasingly important in air pollution forecasting and control. Sectoral emissions significantly impact the accuracy of air quality models and source apportionment. This paper studied the 3DVar (three-dimensional variational) emission inversion method, which is based on machine learning, and then expanded it to sectoral emission inversion combined with source apportionment. Two machine learning conversion matrices were established to implement this method: a matrix that converts the total pollutant concentration to sectoral source apportionment results and a matrix that converts the sectoral source apportionment results to corresponding emissions. Combined with the O3 (ozone) concentration contributed by VOCs (volatile organic compounds) and NOx (nitrogen oxides) precursors in source apportionment, the inversion ability for O3–NOx–VOCs nonlinear processes was improved. Taking the BTH (Beijing‒Tianjin–Hebei) region from January 15 to 30, 2019, as an example, the results revealed that the regional errors of PM2.5 and O3 in the inversion experiment were reduced by 47% and 45%, respectively, and the temporal errors were reduced by 44% and 16%, respectively.

58‐1: A Novel On‐line, Fast Color Correction by Machine Learnings

A new efficient color correction method, utilizing neural network models, is proposed by this study for OLED panels in production, offering a transformative approach to achieve accurate and rapid color calibration. Utilizing transfer learning with a limited dataset, it creates color conversion matrices for AI‐driven color correction. The process involves selecting a similar baseline model from prior batches with a ΔE00 below 1, then refining it using a representative dataset. This model corrects white point and overall color, achieving a ΔE00 less than 2. It corrects 300 data points in less than 4 seconds, demonstrating both speed and accuracy.

PERSPECTIVE FOR ENERGY EXPLOITATION ALONG THE BRAZILIAN COAST

The constant need to supply the growing global energy demand, leads to an increase in the generation of greenhouse gases. To circumvent this problem, more and more alternative means of energy generation have been used to compose the energy grid. One of the alternatives, which in recent decades has received great attention from researchers, is the conversion of wave energy into electrical energy. In Brazil, studies have also gained momentum, and the possibility of implementing wave energy converters on the Brazilian coast is increasingly recognized. With this in mind, the present work aims to determine the regions on the Brazilian coast that are most capable of being explored through wave energy. For this, a simulation of 37 years of the Brazilian sea state, is used in conjunction with a multicriterial methodology, where the logistical and energetic conditions of the Brazilian coast are quantified. Subsequently, power matrices of 8 wave converters are used to quantify the theoretical potential generated in the improved locations. The results showed that, in energy terms, the South and Southeast regions of Brazil have the greatest potential. This factor also proved to be the cause of the presence of lower logistical indexes in these regions, when comparing them with the North and Northeast regions of Brazil. After parameterization of the indices, three zones of interest were observed on the Brazilian coast: Cabo Frio, Imbituba and São José do Norte. When applying the conversion matrices in these locations, average daily generation power between 1.5 and 230kW were observed, the largest being located in the Cabo Frio region, using the BHBA model of converter. Variability in energy production was also discussed, and it should be a primary factor in the choice of the convert model, as well as in its design. Finally, all results were consistent with previous work, however, the path to implementing a wave energy conversion site in Brazil is still long, and should be focused on optimizing devices for Brazilian waters.

Hermite Wavelet Method for Nonlinear Fractional Differential Equations

Nonlinear fractional differential equations (FDEs) constitute the basis for many dynamical systems in various areas of engineering and applied science. Obtaining the numerical solutions to those nonlinear FDEs has quickly gained importance for the purposes of accurate modelling and fast prototyping among many others in recent years. In this study, we use Hermite wavelets to solve nonlinear FDEs. To this end, utilizing Hermite wavelets and block-pulse functions (BPF) for function approximation, we first derive the operational matrices for the fractional integration. The novel contribution provided by this method involves combining the orthogonal Hermite wavelets with their corresponding operational matrices of integrations to obtain sparser conversion matrices. Sparser conversion matrices require less computational load, and also converge rapidly. Using the generated approximate matrices, the original nonlinear FDE is converted into an algebraic equation in vector-matrix form. The obtained algebraic equation is then solved using the collocation points. The proposed method is used to find a number of nonlinear FDE solutions. Numerical results for several resolutions and comparisons are provided to demonstrate the value of the method. The convergence analysis is also provided for the proposed method.

Non-destructive estimation of the cation composition of natural carbonates by micro-Raman spectroscopy

Carbonates play a crucial role in the water and carbon cycles of both geochemical and cosmochemical environments. As carbonates do not exist homogeneously with other minerals in rocks and sands of various sizes, an analytical method that simultaneously satisfies non-destructivity and high spatial resolution has been desired. Further, the ability of semi-quantitative analysis with carbonates-selectivity and without any pre-treatments is added, for its applicability would be extended to remote sensing for deep sea and outer spaces. Here, we focused on the application of micro-Raman spectroscopy, where the vibrational wavenumbers of the translational (T) and librational (L) modes of carbonates are sensitively related to their cation composition. By comparing the semi-quantitative information obtained by X-ray fluorescence spectroscopy, it was found that these vibrational wavenumbers are approximately linearly related to the cation composition. Consequently, a conversion matrix was proposed to estimate the cation composition from the T and L mode vibrational wavenumbers. This method is universally applicable to any cation composition in carbonates, with no background information on the analyte required. To improve the accuracy, conversion matrices were further optimized to three solid-solution series of carbonates. It is worth noting that the proposed conversion matrices are free from matrix effects and do not depend on the total amount of carbonate in a sample. Therefore, the proposed method provides a useful analytical basis for remote sensing of the cation composition of carbonates, both in terrestrial and extra-terrestrial environments.

Evaluating the Sustainability of New Construction Projects over Time by Examining the Evolution of the LEED Rating System

In 1998, the U.S. Green Building Council (USGBC) developed the Leadership in Energy and Environmental Design (LEED) program to provide a standard form of evaluation for sustainability in building design and construction. Since its inception, LEED has undergone seven significant revisions, wherein the expectations needed to achieve the desired certification level were clarified and updated. The reasons for these updates are varied and include the recognition of new technologies and materials, the application of more stringent energy standards, and the recognition of differences in building types. However, the perception within the architecture, engineering, and construction (AEC) industry is that higher certification levels are more challenging to obtain in each subsequent version of LEED. For example, projects receiving a Gold certification under LEED 2.1 may only qualify for a Silver certification under LEED 3.0. The goals of this paper are to review changes in LEED over time and to empirically test this perception. Direct comparisons of the text of the credit requirements were performed between LEED versions (v) 2.1, v2.2, and v3.0 on a credit-by-credit basis. The comparison revealed ten different categories of changes between versions. From this comparison, conversion matrices were developed to allow a project scorecard from an older version of LEED to be converted to a newer version. To address uncertainty resulting from changing the level of detail in the information submitted on project scorecards, both strict and interpretative versions of these matrices were developed. These matrices were then applied to a sample of LEED-certified building projects, drawn using a stratified random sampling procedure from the publicly available USGBC database. The strata were separated first by LEED version (e.g., v2.1, v2.2, and v3.0) and then by certification level (e.g., Certified, Silver, Gold, Platinum). After converting the project scorecards from this sample, qualitative and correlational analyses were performed to test the hypothesis that LEED scores increase over time. The results show that in both strict and interpretive transformations, LEED scores show a slight to moderate increase in points over time.

Quantitative definition of strength of chromophores in gemstones and the impact on color change in pyralspite garnets

AbstractThe color of most garnets is derived from multiple color‐producing elements (chromophores). In this study we selectively isolate the ultraviolet–visible–near infrared (UV–Vis–NIR) spectra of four major chromophores (Fe2+, Mn2+, Cr3+ and V3+) by collecting and extrapolating the spectra of four representative pyrope‐almandine‐spessartine (pyralspite) garnets. In order to study the color strength of these isolated chromophores and their impact on color change in garnet, we have proposed a new quantitative definition of strength of a chromophore. With the isolated garnet chromophore spectra, hypothetical garnet spectra with various chemical compositions can be simulated. By using these hypothetical garnet spectra, the impact of each chromophore on the color change behavior in pyralspite garnet was also quantitatively studied. Most pyralspite garnets can be successfully modeled using these four chromophores, however, this model cannot adequately describe those garnets containing the Fe3+/Fe2+ intervalence charge‐transfer transitions. Finally, a comprehensive excel data processing template (Appendix 3) written with VBA macro code was generated to help other researchers calculate colorimetric parameters and color panels from UV–Vis–NIR spectrum. In the template, we provided multiple types of conversion matrices and power distribution curves of different illuminants, so that different colorimetric parameter conversion and color panel calculation from UV–Vis–NIR spectrum can be selected with different combinations based on people's preference. The user guide of the excel template can be found in Appendix 4. The detailed calculation procedures and formulae used for the excel template can be found in Appendix 5.

Research on aeromagnetic three-component error compensation technology for multi-rotor UAV

Aeromagnetic three-component data contain a large amount of geomagnetic information, which can help to obtain a quantitative interpretation of a magnetic anomaly and to improve the identification accuracy of an abnormal body. However, aeromagnetic three-component data of an unmanned aerial vehicle (UAV) include the carrier fixed interference error, inductive interference error, eddy current interference error, and attitude error. Therefore, carrier interference compensation and attitude compensation are necessary to obtain three-component data in a geographical coordinate system. This paper analyzes the difference of six types of attitude conversion matrices for the mutual conversion between the geographic and carrier coordinate systems. Based on the analysis results, the yaw-pitch-roll sequence has the smallest error when calculating the attitude conversion, so the compensation sequence of the roll-pitch-yaw is selected for attitude compensation. The characteristics of the UAV carrier interference error are also analyzed. A low-pass filter is set up for data preprocessing according to the high-frequency characteristics of the carrier eddy current interference, and carrier fixed interference and induction interference compensation models are constructed based on the Tolles-Lawson model. The aeromagnetic three-component comprehensive compensation error objective function is established by integrating attitude compensation and carrier interference compensation. In addition, an adaptive step-size cuckoo algorithm is proposed to obtain the minimum value of the objective function to solve 12 compensation parameters so that the accurate three-component data can be obtained quickly, efficiently, and accurately. Finally, a comprehensive compensation experiment is performed on the three-component aeromagnetic data, and the mean error of the three-component data after compensation is reduced to less than 0.72 nT.

Circumferential crack modeling of thin cylindrical shells in modal deformation

An innovative technique, called conversion, is introduced to model circumferential cracks in thin cylindrical shells. The semi-analytical finite element method is applied to investigate the modal deformation of the cylinder. An element including the crack is divided into three sub-elements with four nodes in which the stiffness matrix is enriched. The crack characteristics are included in the finite element method relations through conversion matrices and a rotational spring corresponding to the crack. Conversion matrices obtained by applying continuity conditions at the crack tip are used to transform displacements of the middle nodes to those of the main nodes. Moreover, another technique, called spring set, is represented based on a set of springs to model the crack as a separated element. Components of the stiffness matrix related to the separated element are incorporated while the geometric boundary conditions at the crack tip are satisfied. The effects of the circumferential mode number, the crack depth and the length of the cylinder on the critical buckling load are investigated. Experimental tests, ABAQUS modeling and results from literature are used to verify and validate the results and derived relations. In addition, the crack effect on the natural frequency is examined using the vibration analysis based on the conversion technique.

Fault isolation and fault-tolerant control for Takagi-Sugeno fuzzy time-varying delay stochastic distribution systems

A fault isolation, estimation, and fault-tolerant control (FTC) scheme for nonlinear time-varying delay stochastic distribution control systems was presented in this paper. The Takagi-Sugeno fuzzy model was adopted to approach the nonlinear dynamics of time-varying delay systems. According to the output equivalence principle and Laplace transformation, an augmented state vector was given to solve the time-varying delay problem. When multiple actuator faults and interference occur simultaneously, fault detection, isolation and fault estimation was designed to obtained the fault information. To decouple faults and obtain the value and location information of the fault, the system was separated into two parts through the designed multiple conversion matrices, in which one subsystem was only affected by one actuator fault. This has simplified the design of fault isolation and estimation. A adaptive observer for fault estimation was given. Then, fault information such as the time, location, and size was determined. The observer gain matrices were calculated using linear matrix inequality (LMI). When a fault was detected and diagnosed, a FTC algorithm was devised using the proportional-integral control scheme to compensate the fault as much as possible. It has been shown that even if multiple faults actuator occurred simultaneously, the FTC controller still ensured the output probability density function of the system traced the desired probability density function when a fault occurred. Finally, the expected results were obtained through the simulation example, which confirmed the effectiveness of the method.

Two-Level Stability Analysis of Complex Circuits

A new methodology is proposed for the small- and large-signal stability analysis of complex microwave systems, containing multiple active blocks. It is based on a calculation of the system characteristic determinant that ensures that this determinant does not exhibit any poles on the right-hand side (RHS) of the complex plane. This is achieved by partitioning the structure into simpler blocks that must be stable under either open-circuit (OC) or short-circuit (SC) terminations. Thus, the system stability is evaluated using a two-level procedure. The first level is the use of pole-zero identification to define the OC- or SC-stable blocks, which, due to the limited block size, can be applied reliably. In large-signal operation, the OC- or SC-stable blocks are described in terms of their outer-tier conversion matrices. The second level is the calculation and analysis of the characteristic determinant of the complete system at the ports defined in the partition. The roots of the characteristic determinant define the stability properties. The Nyquist criterion can be applied since, by construction, the determinant cannot exhibit any poles in the RHS. In addition, one can use pole-zero identification to obtain the values of the determinant zeroes. Because the determinant is calculated at a limited number of ports, the analysis complexity is greatly reduced.

Color conversion matrices in digital cameras: a tutorial

Color conversion matrices and chromatic adaptation transforms (CATs) are of central importance when converting a scene captured by a digital camera in the camera raw space into a color image suitable for display using an output-referred color space. In this article, the nature of a typical camera raw space is investigated, including its gamut and reference white. Various color conversion strategies that are used in practice are subsequently derived and examined. The strategy used by internal image-processing engines of traditional digital cameras is shown to be based upon color rotation matrices accompanied by raw channel multipliers, in contrast to the approach used by smartphones and commercial raw converters, which is typically based upon characterization matrices accompanied by conventional CATs. Several advantages of the approach used by traditional digital cameras are discussed. The connections with the color conversion methods of the DCRaw open-source raw converter and the Adobe digital negative converter are also examined, along with the nature of the Adobe color and forward matrices.

Three-dimensional spine morphology measuring technology for daily surface monitoring

In order to conduct surface monitoring of the three-dimensional spine morphology of the human body in daily life, a spine morphology measuring method using "single camera, multi-view" to construct stereo vision is proposed. The images of the back of the human body with landmarks of spinous process are captured from multiple angles by moving a single camera, and based on the "Zhang Zhengyou calibration method" and the triangulation principle of binocular stereo vision, the spatial conversion matrices corresponding to each other between all images and the 3D coordinates of the landmarks are calculated. Then the spine evaluation angle used to evaluate the spine morphology is further calculated. The tests' results showed that the spine evaluation angle error of this method is within ±3°, and the correlation between the results and the X-ray film Cobb angles is 0.871. The visual detection algorithm used in this paper is non-radioactive, and because only one camera is used in the measurement process and there is no need to pre-set the camera's shooting pose, the operation is simple. The research results of this article can be used in a mobile phone-based intelligent detection system, which will be suitable for the group survey of scoliosis in communities, schools, families and other occasions, as well as for the long-term follow-up of confirmed patients. This will provide a reference for doctors to diagnose the condition, predict the development trend of the condition, and formulate treatment plans.

A novel approach for reducing complexity in the SLM-GFDM system

The flexible nature of generalized frequency division multiplexing (GFDM) leads to superimposition of multiple subsymbols in time domain, the consequence of which is high PAPR. Selective mapping (SLM) is one of the prominent PAPR reduction techniques in GFDM, which uses bank of modulation matrices to generate a set of alternative signal representations. This procedure increases the complexity of the GFDM system enormously. In this paper, we utilize the concepts of conversion matrices and linearity to achieve low complexity with respect to the modulation matrices in the conventional SLM method. By using the proposed conversions we evolve at three modified SLM schemes which have much lower complexity. The first method uses the principle of linearity and two GFDM signals to generate the set of candidate signals while the second one uses only one GFDM signal along with conversion matrix. By adhering the advantages of two methods, the third method adds the concept of shifting matrix, which is an effective solution for tradeoff between PAPR performance and computational complexity. The obtained simulation results indicate that, when compared to conventional SLM scheme, the first proposed approach has inferior PAPR reduction performance, whereas, second and third proposed methods almost reach the performance of the conventional SLM scheme.

Inter- and intra-annual variability of potential power production from wave energy converters

Estimation of the variability in the electrical power production and performance over the life-time of wave energy converters (WEC) is paramount for the economic viability of potential wave farm projects. In this research, the significance of the inter-annual variability in the potential production performance (PPP) is demonstrated, using power conversion matrices of ten pre-commercial WEC devices and an existing 31-year wave hindcast case study from the central shelf of New South Wales, Australia. The variability in the PPP over the intra- and inter-annual time scales is found to be comparable, hence indicating that making predictions merely based on annual and monthly averages could be misleading and that inter-annual fluctuations should be considered in future analysis. The results also show that inter-annual variations in WEC production performance can be significantly higher than that of the wave energy resource (WER) owing to the efficiency of different WECs relative to the local sea state conditions. We also demonstrate that optimization of WEC performance for the local sea state cannot only potentially lead to improved power yields but also a decrease in the intra- and inter-annual variability in PPP.

Theory, Simulation, and Experiment on Extended Mixed-Mode S-Parameters in Three-Conductor Lines

This paper proposes novel mixed-mode S -parameters, which are dubbed as “extended mixed-mode S -parameters.” The extended mixed-mode S -parameters were applied to three-conductor transmission lines, resulting in the independent differential and common modes using the current division factor of three-conductor transmission lines. By contrast to the conventional mixed-mode S -parameters, there are no cross-mode S -parameters in the extended mixed-mode S -parameters, even in the asymmetrical conductor transmission lines. In addition, two new mode conversion matrices, which contain the current division factor, are also proposed to convert the extended mixed-mode S -parameters to the standard S -parameters. The validity of the proposed extended mixed-mode S -parameters and the mode conversion method were confirmed by comparing the S -parameters from the theory, EM-simulation, and experiment as well.

Fast polynomial transforms based on Toeplitz and Hankel matrices

Many standard conversion matrices between coefficients in classical orthogonal polynomial expansions can be decomposed using diagonally-scaled Hadamard products involving Toeplitz and Hankel matrices. This allows us to derive algorithms with an observed complexity ofO(Nlog2N)\mathcal {O}(N\log ^2 \! N), based on the fast Fourier transform, for converting coefficients of a degreeNNpolynomial in one polynomial basis to coefficients in another. Numerical results show that this approach is competitive with state-of-the-art techniques, requires no precomputational cost, can be implemented in a handful of lines of code, and is easily adapted to extended precision arithmetic.

Image Restoration for Fluorescence Planar Imaging with Diffusion Model.

Fluorescence planar imaging (FPI) is failure to capture high resolution images of deep fluorochromes due to photon diffusion. This paper presents an image restoration method to deal with this kind of blurring. The scheme of this method is conceived based on a reconstruction method in fluorescence molecular tomography (FMT) with diffusion model. A new unknown parameter is defined through introducing the first mean value theorem for definite integrals. System matrix converting this unknown parameter to the blurry image is constructed with the elements of depth conversion matrices related to a chosen plane named focal plane. Results of phantom and mouse experiments show that the proposed method is capable of reducing the blurring of FPI image caused by photon diffusion when the depth of focal plane is chosen within a proper interval around the true depth of fluorochrome. This method will be helpful to the estimation of the size of deep fluorochrome.

Detection of elevated pulmonary pressures by the ECG-derived ventricular gradient: A comparison of conversion matrices in patients with suspected pulmonary hypertension

BackgroundThe aim was to assess the diagnostic value of the Inverse Dower (INVD)-derived vectorcardiogram (VCG) and the Kors-derived VCG to detect elevated systolic pulmonary artery pressure (SPAP) in suspected pulmonary hypertension (PH). MethodsIn 132 patients, morphologic variables were evaluated by comparing the VCG parameters synthesized by INVD and Kors matrix. Comparison of the diagnostic accuracy of detecting SPAP ≥50mmHg between the matrices was performed by ROC curve analysis and logistic regression analysis. ResultsMost VCG parameters differed significantly between INVD and Kors. ROC analysis for detection of SPAP ≥50mmHg by VG projected on the X-axis demonstrated no difference (p=0.99) between INVD (AUC=0.80) and Kors (AUC=0.80). Both the INVD- and Kors-derived VCG provided significant diagnostic information on the presence of SPAP ≥50mmHg (INVD, OR 1.05, 95%CI 1.03–1.07; P<0.001; Kors, OR 1.05, 95%CI 1.03–1.08; P<0.001). ConclusionAlthough there were significant differences in measures of vector morphology, both INVD- and Kors-derived VCG demonstrated equal clinical performance in case of elevated SPAP.

New SLM scheme to reduce the PAPR of OFDM signals using a genetic algorithm

Abstract Selected mapping (SLM) is a popular peak-to-average power ratio (PAPR) reduction technique suitable for use in orthogonal frequency division multiplexing (OFDM) systems as it achieves good PAPR reduction performance without signal distortion. However, SLM requires a bank of inverse fast Fourier transforms (IFFTs) to produce candidate signals, resulting in high computational complexity. In this paper, we introduce a novel SLM technique based on conversion matrices (CM) and a genetic algorithm (GA) that requires only one IFFT module. Simulation results indicate that the proposed method obtains desirable PAPR reduction performance with low computational complexity.