Harmonic Model Research Articles

An Integrated Scheme of FIR and Augmented Real-Valued Time-Delay Neural Network of Harmonic Cancellation Digital Predistortion Model for High-Frequency Power Amplifier

An Integrated Scheme of FIR and Augmented Real-Valued Time-Delay Neural Network of Harmonic Cancellation Digital Predistortion Model for High-Frequency Power Amplifier

Model integration of circadian- and sleep-wake-driven contributions to rhythmic gene expression reveals distinct regulatory principles

Analyses of gene-expression dynamics in research on circadian rhythms and sleep homeostasis often describe these two processes using separate models. Rhythmically expressed genes are, however, likely to be influenced by both processes. We implemented a driven, damped harmonic oscillator model to estimate the contribution of circadian- and sleep-wake-driven influences on gene expression. The model reliably captured a wide range of dynamics in cortex, liver, and blood transcriptomes taken from mice and humans under various experimental conditions. Sleep-wake-driven factors outweighed circadian factors in driving gene expression in the cortex, whereas the opposite was observed in the liver and blood. Because of tissue- and gene-specific responses, sleep deprivation led to a long-lasting intra- and inter-tissue desynchronization. The model showed that recovery sleep contributed to these long-lasting changes. The results demonstrate that the analyses of the daily rhythms in gene expression must take the complex interactions between circadian and sleep-wake influences into account. A record of this paper's transparent peer review process is included in the supplemental information.

Harmonic State-Space Modeling and System Characteristic Analysis of Grid-Connected Inverter Parallel-Operation System Considering Asynchronous Carriers

Harmonic State-Space Modeling and System Characteristic Analysis of Grid-Connected Inverter Parallel-Operation System Considering Asynchronous Carriers

Photovoltaic Capacity Management for Investment Effectiveness

The production of photovoltaic utility varies within the day/night cycle. At night, photovoltaic cells do not produce anything. However, their day-light production, unconsumed on a current basis and exported to the grid, is compensated for with supply from the grid at night. This scheme of exploitation is called net-metering and is considered herein. Solar energy produced by a prosumer and fed into the grid has to be equal to the electricity supplied from the grid at night; otherwise, a shortage or waste of photovoltaic production occurs. The above finding leads us to the proposition for the optimal solution of photovoltaic capacity. We derived a closed-form capacity solution to the maximized non-linear profit function. It solves harmonic and 2-point production functions that vary symmetrically around the mean production. To verify the solution methodology, harmonic and 2-point models from empirical production data are estimated. Then, the solution is presented together with its return rate and internal return rate. The main finding is that the unit cost of the grid electricity, photovoltaic capacity unit cost and exploitation time all affect the total profit and return rate values while not impacting the optimal capacity of the photovoltaics. The optimal capacity depends on the prosumer’s energy consumption volume and on the natural conditions of production captured here by the technology efficiency coefficient estimated from the production time series.

Determining effective sampling frequencies for transient pressure events in water distribution systems optimal sampling for WDS transients

This study introduces a novel methodology for determining the optimal frequency for pressure data acquisition in water distribution systems (WDSs) in response to transient-flow events such as pipe ruptures. By leveraging actual design and operational data, we simulated potential rupture scenarios and their resultant pressure wave patterns through transient-flow analysis. Harmonic series modeling was used to identify significant periods that closely replicate the observed pressure-wave time series. This allowed the derivation of recommended data acquisition intervals tailored to each monitoring site within the network. The proposed approach facilitates comprehensive analysis of all possible hydraulic shock scenarios, which can provide insights into both the existing monitoring infrastructure and strategic planning in the design phase of the WDS. Although the methodology focuses on rupture events, its application can extend to various water-quality indicators and flow rates, albeit with consideration of their typically static behavior.

UHV AC/DC power grid geomagnetically induced currents harmonic characteristics analysis

The power grid’s geomagnetically induced currents (GIC) during geomagnetic storms, are associated with a broad and abrupt harmonic impact, with the potential for grid paralysis and extensive power outages in severe scenarios. Therefore, the harmonic characteristics of geomagnetically induced currents in China’s ultra-high voltage (UHV) AC/DC power grid are analyzed in this paper. Firstly, a harmonic equivalent model of transformer GIC is established, and the injection of harmonics into the UHV AC/DC power grid during GIC events is quantified.Secondly, a harmonic state-space model is established by combining the 12-pulse converter switching function theory with the exponential Fourier series. The harmonic transmission and dynamic coupling characteristics of GIC in the UHV AC/DC power grid are analyzed using the harmonic equivalent model of the main transformer GIC and the harmonic equivalent model of the converter transformer GIC. Finally, a harmonic simulation model of the UHV AC/DC power grid under GIC is constructed using PSCAD, and the distribution of harmonics in the UHV AC/DC power grid under GIC is calculated. The calculations indicate that with 30 A injected GIC in the sending end transformers, the 2nd harmonic current on the sending end network side alone is 61.45 A, and the 3rd harmonic voltage on the valve side is 8.57 kV. The characteristics of harmonic transmission in the power grid result in a 2nd harmonic current of 34.87 A on the receiving end network side. Simultaneously, the total harmonic distortion of the AC power grid at the sending end is 2.35 %, surpassing the permissible limit established by the national standard. Consequently, this issue should be prioritized by the relevant power authorities.

Exact counterdiabatic driving in finite topological lattice models

Adiabatic protocols are often employed in state preparation schemes but require the system to be driven by a slowly varying Hamiltonian so that transitions between instantaneous eigenstates are exponentially suppressed. Counterdiabatic driving is a technique to speed up adiabatic protocols by including additional terms calculated from the instantaneous eigenstates that counter diabatic excitations. However, this approach requires knowledge of the full eigenspectrum meaning that the exact analytical form of counterdiabatic driving is only known for a subset of problems, e.g., the harmonic oscillator and transverse field Ising model. We extend this subset of problems to include the general family of one-dimensional noninteracting lattice models with open boundary conditions and arbitrary onsite potential, tunneling terms, and lattice size. We will derive a general analytical form for the counterdiabatic term for all states of lattice models, including bound and in-gap states which appear, e.g., in topological insulators. We also derive the general analytical form of targeted counterdiabatic driving terms which are tailored to enforce the dynamical state to remain in a specific state. As an example of the use of the derived analytical forms, we consider state transfer using the topological edge states of the Su-Schrieffer-Heeger model. The derived analytical counterdiabatic driving Hamiltonian can be utilized to inform control protocols in many-body lattice models or to probe the nonequilibrium properties of lattice models. Published by the American Physical Society 2024

Harmonic modelling and control of dual active bridge converter for DC microgrid applications

Due to the intermittent power availability from renewable sources, the bidirectional DC-DC converter (BDC) must integrate with the energy storage system for bidirectional power flow. Among many BDCs, the Dual Active Bridge (DAB) converter is the most promising because of the system's power handling capacity and efficiency. DAB bidirectional DC-DC converter is a topology with the advantages of a decreased number of devices, soft-switching commutations, low cost, and high efficiency. This work describes the guidelines for designing a DAB converter for small DC microgrid applications. It is shown that the judicial selection of reactive elements leads to soft switching for all the switches in the converter in varying load conditions. A guideline for the controller design is given and the operations are validated through the simulation. A harmonic modelling technique has been implemented to model the DAB converter based on an efficient closed-loop regulator. A solar PV system has also been implemented here with a SEPIC converter that is used as an interfacing element between the PV system and the load bus. At last, a DC Microgrid is simulated in a PSIM environment to showcase its various modes of operation. It is shown that the battery bank can support variable loads independently through the DAB converter. In inadequate solar power generation, load power demand is shared between the battery and PV system. In case of deep discharge of the battery, the PV system can charge the battery through a DAB converter.

Strong coupling in an asymmetric two-dimensional guided mode resonance metasurface structure and enhancement for optical third-harmonic generation

A two-dimensional guided mode resonance structure supports a transverse magnetic (TM) resonant mode in the direction of incident polarization and a transverse electric (TE) resonant mode in the direction perpendicular to the polarization. In this work, the coupling between the transverse magnetic and the transverse electric resonant modes in an asymmetric two-dimensional dielectric metasurface structure is investigated. The asymmetric structure consists of a two-dimensional square nanohole array etched in a titanium dioxide thin film on a transparent silica substrate. With finite difference time domain simulations, anti-crossing of the resonant spectra of the TM and TE modes is observed by adjusting the asymmetry of the structure. The anti-crossing indicates that the interaction between TM and TE resonant modes results in a strong coupling state. A coupled harmonic oscillator model is used to explain the strong coupling effect. The results of the coupled harmonic oscillator modeling agree well with the results of numerical simulations. Furthermore, it is shown that the strong coupling can significantly enhance the third harmonic generation intensity compared with the uncoupled TM and TE resonant modes.

Research on modal combination coefficients considering the spectral characteristics of strong ground motion

To address the limitations of traditional complete quadratic combination (CQC) modal combination coefficients in calculating ground motions with narrow bandwidth and long periods, a revised methodology is proposed. The new CQC modal combination coefficients are formulated by considering the spectral characteristics of strong ground motion, taking the modified Kanai-Tajimi spectrum model as a prerequisite, and applying random vibration theory. Simultaneously, a random phase simple harmonic process model for a single harmonic component is established, and corresponding combination coefficients are provided. The necessity and rationality of considering the spectral characteristics of strong ground motion are demonstrated from three perspectives: differences in power spectral models, variations in combination coefficients, and the inherent combination mechanism. As an illustrative example, the layer shear model is analyzed and compared with the results of the structure's modal combination taking different combination coefficients. This comparison is conducted under the influence of long-period simple harmonic waves, four natural seismic waves in the basin, and the 50 natural ground motions suggested by ATC-63, respectively. The results indicate that the modal combination coefficients developed by considering the spectral characteristics of strong ground motions are more reasonable and can serve as a viable replacement for traditional CQC combination rules. This is especially advantageous when dealing with ground motion inputs characterized by narrow bandwidth and long periods, providing significant benefits in such scenarios.

Inter- and sub-harmonics estimation: Treatise on raptor-inspired Harris Hawks collective wisdom

In contemporary power systems, harmonics as undesired electrical phenomena, have drawn considerable attention of the research community investigating in design and development of optimal electrical networks. Harmonics affect the power electronics devices with a number of negative impacts, including higher power losses, worse power quality, and interference with other delicate grid connected equipment. An objective function of inter- and sub-harmonics is constructed for joint estimation of amplitude and phase with known frequency. Accurate estimation of the harmonics model is carried out with stupendous knacks of raptor-inspired Harris Hawks optimization algorithm (HHOA), a revolutionary population-based, nature-motivated optimization approach. The primary sources of inspiration for HHOA are Harris Hawks cooperative demeanor and surprise pounce chasing style in nature. The HHOA’s performance is assessed for harmonics parameter estimation with several noise conditions, differing particle sizes and iterations. The proposed HHOA-based estimation technique provides accurate, convergent and robust performance for harmonics estimation. The reliable level of fitness is achieved consistently in the range of 10−3 to 10−10, an evidence of valuable precision, stability and robustness of the proposed algorithm.

Harmonization radiomics model to predict immune checkpoint inhibitor-related pneumonitis (CIP) in patients with non-small cell lung cancer (NSCLC).

12142 Background: The increasing use of immunotherapy in advanced non-small cell lung cancer (NSCLC) presents a significant challenge in managing adverse events, particularly checkpoint inhibitor-associated pneumonitis (CIP). This potentially life-threatening complication often necessitates discontinuation of immunotherapy, even in patients experiencing tumor response. Presently, there are no reliable models to predict the onset of CIP. This research utilizes CT radiomics to create an innovative approach for anticipating the risk of CIP in patients with NSCLC. Methods: This IRB-approved, retrospective study analyzed data from 159 stage III-IV NSCLC patients undergoing immunotherapy. We categorized patients into pneumonitis (further subdivided into immunotherapy-induced, radiation-induced, and others) and non-pneumonitis groups. Using LIFEx software, we extracted 3D-radiomic features from both tumors and surrounding 1cm thick peritumoral regions. To address scanner-associated variations, a linear mixed-effect radiomics harmonization model was applied. A Random Forest algorithm was then used to develop a classification model predicting CIP occurrence based on the pre-treatment CT radiomic and clinical data. The dataset was split into training (70%) and test (30%) sets. The accuracy of predictions was evaluated using confusion matrix statistics and bootstrapping with 1,000 iterations for median and 95% confidence interval (CI). The performance metrics included sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area under the ROC curve (AUC). Results: 159 patients were analyzed, of which only 19 had checkpoint inhibitor-related pneumonitis. Among which, 17 (54.8%) patients had grade 1 pneumonitis, 12 (38.7%) patients had grade 2 pneumonitis, 2 (6.5%) patients had grade 3 pneumonitis, and none had grade 4 or grade 5 pneumonitis. The model achieved a sensitivity of 0.98 (0.97, 0.99), a specificity of 0.08 (0.05, 0.14), a PPV of 0.91 (0.90, 0.91), and an NPV of 0.33 ± 0.23 for predicting CIP. The AUC of 0.59 (0.56, 0.66) indicates that the model may predict checkpoint inhibitor-associated pneumonitis with an accuracy of 59%. Conclusions: The study provides insights into the potential of radiomic analysis coupled with AI algorithms and the use of harmonization model in predicting CIP among NSCLC patients treated with immunotherapy. However, larger studies are needed to validate our findings and the utility of harmonization models in predicting CIP.

Pre-treatment CT radiomics for predicting immunotherapy response in non-small cell lung cancer(NSCLC): RECIST vs. irRECIST criteria.

e20613 Background: Accurate prediction of how patients with non-small cell lung cancer (NSCLC) will respond to immunotherapy is essential for customizing individual treatment plans. This research explores the use of radiomics analysis from pre-treatment CT scans as a method to predict the effectiveness of immunotherapy in individuals with NSCLC. Methods: This IRB-approved retrospective study investigated radiologic and clinical data from 159 patients with stage III-IV NSCLC treated with immunotherapy. Imaging responses were assessed according to RECIST 1.1 and immune-related RECIST (irRECIST) criteria at least twice during a 24-week period. Responses were categorized as complete response (CR), partial response (PR), stable disease (SD), and progressive disease (PD). 3D radiomics features were extracted from both the tumor and a 1 cm thick peritumoral region. A linear mixed-effect harmonization model was employed to correct for scanner-associated variations. A Random Forest algorithm was used to develop a classification model to predict response according to RECIST 1.1 or irRECIST. The dataset was split into training (70%) and test (30%) sets. The accuracy of predictions was evaluated using confusion matrix statistics and bootstrapping with 1,000 iterations for median and 95% confidence interval (CI). Results: Using RECIST 1.1 criteria, 41 patients (25.2%) achieved PR and CR(0.6), 62 (39.0%) achieved SD, and 56 (35.2%) achieved PD. IrRECIST criteria yielded slightly higher CR/PR rates with 52 patients (32.7%), while SD decreased to 65 (41.0%) and PD remained at 42 (26.4%). For predicting CR/PR and SD responses, the models achieved a sensitivity of 0.45 (95% CI: 0.38-0.50) and 0.64 (0.60-0.68) for irRECIST, compared to 0.34 (0.28-0.38) and 0.55 (0.52-0.60) for RECIST 1.1. The corresponding specificity was 0.85 (0.83-0.87) and 0.63 (0.59-0.67) for irRECIST, compared to 0.91 (0.89-0.93) and 0.67 (0.63-0.72) for RECIST 1.1. For predicting PD response, the models achieved a sensitivity of 0.49 (0.45-0.56) for irRECIST and 0.57 (0.52-0.62) for RECIST 1.1. The models' balanced accuracy for predicting CR/PR, SD, and PD were 0.65 (0.61-0.68), 0.64 (0.61-0.67), and 0.65 (0.63-0.69) for irRECIST, compared to 0.62 (0.59-0.64), 0.61 (0.59-0.64), and 0.62 (0.59-0.64) for RECIST 1.1, respectively. Conclusions: This study demonstrates the potential of pre-treatment CT radiomics to predict immunotherapy responses in NSCLC patients, offering insights into personalized treatment approaches. However, larger studies are needed to validate our findings.

Highly sensitive and label-free protein immunoassay-based biosensor comprising infrared metamaterial absorber inducing strong coupling

A mid-infrared label-free immunoassay-based biosensor is an effective device to help identify and quantify biomolecules. This biosensor employs a surface-enhanced infrared absorption spectroscopy, which is a highly potent sensing technique for detecting minute quantities of analytes. In this study, a biosensor was constructed using a metamaterial absorber, which facilitated strong coupling effects. For maximum coupling effect, it is necessary to enhance the near-field intensity and the spatial and spectral overlap between the optical cavity resonance and the vibrational mode of the analyte. Due to significant peak splitting, conventional baseline correction methods fail to adequately analyze such a coupling system. Therefore, we employed a coupled harmonic oscillation model to analyze the spectral distortion resulting from the peak splitting induced by the strong coupling effect. The proposed biosensor with a thrombin-binding aptamer-based immunoassay could achieve a limit of detection of 267.4 pM, paving the way for more efficient protein detection in clinical practice.

Envelope Extraction Algorithm for Magnetic Resonance Sounding Signals Based on Adaptive Gaussian Filters

Magnetic resonance sounding is a geophysical method for quantitatively determining the state for groundwater storage that has gained international attention in recent years. However, the practical acquisition of magnetic resonance sounding signals, which are on the nanovolt scale, is susceptible to various types of interference, such as power-line harmonics, random noise, and spike noise. Such interference can degrade the quality of magnetic resonance sounding signals and, in severe cases, be completely drowned out by noise. This paper introduces an adaptive Gaussian filtering algorithm that is well-suited for handling intricate noise signals due to its adaptive solving characteristics and iterative sifting approach. Notably, the algorithm can process signals without relying on prior knowledge. The adaptive Gaussian filtering algorithm is applied for the envelope extraction of noisy magnetic resonance sounding signals, and the reliability and effectiveness of the method are rigorously validated. The simulation results reveal that, even under strong noise interference (with original signal-to-noise ratios ranging from −7 dB to −25 dB), the magnetic resonance sounding signal obtained after algorithmic processing is compared to the ideal signal, with 16 sets of data statistics, and the algorithm ensures an initial amplitude uncertainty within 4nV and restricts the uncertainty of the relaxation time within a 6 ms range. The signal-to-noise ratio can be boosted by up to 53 dB. The comparative assessments with classical algorithms such as empirical mode decomposition and the harmonic modeling method confirm the superior performance of the adaptive Gaussian filtering algorithm. The processing of the field data also fully proved the practical application effects of the algorithm.

Revisiting the Numerical Evaluation and Visualization of the Gravity Fields of Asteroid 4769 Castalia Using Polyhedron and Harmonic Expansions Models

For the convenience of comparison with previous literature, the gravity calculations are revisited for the Asteroid 4769 Castalia, but with extensions on its surface and on intersecting planes and spheres around it, using the polyhedron and harmonic expansion methods with different order and degree for different cases, especially including the gravitational accelerations inside the asteroid, which did not appear at all before. In these evaluations, a few different facts of the these methods and results are revealed, such as the fact that gravity diverges when the position radius is less than the mean radius from harmonic-expansion method, and the maximum gravity is not at the deep valley and mountain top. For a surface that intersects the asteroid, the maximum gravity on it is at the intersection lines between the asteroid surface and the spheres or planes. This means that on the sphere and the plane, the gravities inside and outside the asteroid are smaller than the gravity on the intersection, i.e., on the surface. Some analyses of these conclusions are given with many examples with different radii of the sphere and with different order and degree harmonic expansion models for the above asteroid surface and surrounding spheres. It is interesting to note that very few researchers know that the polyhedral method can also be used to calculate the gravity inside an asteroid with just some modifications of the code. Some special gravity figures on surface and planes inside the asteroid Castalia are computed and made for the first time. The calculations also include tangential gravity, potential, and gravitational slope on surface. Specifically, we find that the overall mean gravitational slope could be one kind of indicator of the density of an asteroid. The minimum overall mean slope happens when the asteroid density is about 2.9 g/cm3, which is much larger than a usually assumed value between 1.7 and 2.5 for asteroid Castalia when its period is 4.07 h, since rotation period should be a more accurate parameter than its estimated density. These conclusions about this typical prolate-like asteroid could be a benchmark for analyzing other similar asteroids.

Wave‐to‐Wire Model and Output Performance Analysis of a Point Absorption Wave Energy Converter Based on Triboelectric Nanogenerator

Herein, a point absorption wave energy converter (WEC) model combined with a contact–separation mode triboelectric nanogenerator (PAW TENG) is proposed. The model considers the interaction between the hydrodynamic forces captured by a point absorption conversion device of wave energy and the electrostatic force of the TENG. According to the established harmonic oscillation model of the buoy, the buoy's hydrodynamic properties and power generation characteristics are studied using finite element simulation and numerical simulation calculations. The best matching resistor circuit for PAW TENG in regular waves is investigated and analyzed. The electrical characteristics of the PAW TENG in the irregular wave spectrum are also solved. This work will provide design ideas for the experimental design of a novel point absorption WEC.

Harmonizing three-dimensional MRI using pseudo-warping field guided GAN

In pursuit of cultivating automated models for magnetic resonance imaging (MRI) to aid in diagnostics, an escalating demand for extensive, multisite, and heterogeneous brain imaging datasets has emerged. This potentially introduces biased outcomes when directly applied for subsequent analysis. Researchers have endeavored to address this issue by pursuing the harmonization of MRIs. However, most existing image-based harmonization methods for MRI are tailored for 2D slices, which may introduce inter-slice variations when they are combined into a 3D volume. In this study, we aim to resolve inconsistencies between slices by introducing a pseudo-warping field. This field is created randomly and utilized to transform a slice into an artificially warped subsequent slice. The objective of this pseudo-warping field is to ensure that generators can consistently harmonize adjacent slices to another domain, without being affected by the varying content present in different slices. Furthermore, we construct unsupervised spatial and recycle loss to enhance the spatial accuracy and slice-wise consistency across the 3D images. The results demonstrate that our model effectively mitigates inter-slice variations and successfully preserves the anatomical details of the images during the harmonization process. Compared to generative harmonization models that employ 3D operators, our model exhibits greater computational efficiency and flexibility.

Harmonization of Authority in the Investigation of the Financial Services Sector in Indonesia

The rapid growth of the financial services sector in Indonesia demonstrates its strategic role in the national economy. However, harmonizing investigative authorities in this sector poses a challenge that needs to be addressed to maintain stability and public trust. This paper aims to investigate the issue of harmonizing investigative authorities in the Indonesian financial services sector, focusing on regulatory frameworks, case developments, and potential harmonization models. The evolution of investigative authority regulations in the financial services sector is outlined, identifying weaknesses in the system that need to be addressed. Case studies provide a concrete overview of the challenges faced in field investigations. A harmonization model for investigative authorities is proposed as a solution to enhance the effectiveness and efficiency of investigations. Under this harmonization model, OJK investigators are not the sole authority to conduct investigations in the financial services sector, but their authority must be elaborated with that of the POLRI or PPNS investigators as regulated in the Criminal Procedure Code (KUHAP). Article 49 paragraph (5) of Law No. 4 of 2023 concerning Financial Services Sector (P2SK Law), which essentially states that criminal investigations in the financial services sector can only be conducted by OJK investigators through a harmonization model of investigative authority in the financial services sector in Indonesia, should be elaborated so that investigative authority in the financial services sector can be carried out by POLRI or PPNS with the assistance of OJK investigators.

Instantaneous Marcus theory for photoinduced charge transfer dynamics in multistate harmonic model systems

Modeling the dynamics of photoinduced charge transfer (CT) in condensed phases presents challenges due to complicated many-body interactions and the quantum nature of electronic transitions. While traditional Marcus theory is a robust method for calculating CT rate constants between electronic states, it cannot account for the nonequilibrium effects arising from the initial nuclear state preparation. In this study, we employ the instantaneous Marcus theory (IMT) to simulate photoinduced CT dynamics. IMT incorporates nonequilibrium structural relaxation following a vertical photoexcitation from the equilibrated ground state, yielding a time-dependent rate coefficient. The multistate harmonic (MSH) model Hamiltonian characterizes an organic photovoltaic carotenoid-porphyrin-fullerene triad dissolved in explicit tetrahydrofuran solvent, constructed by mapping all-atom inputs from molecular dynamics simulations. Our calculations reveal that the electronic population dynamics of the MSH models obtained with IMT agree with the more accurate quantum-mechanical nonequilibrium Fermi’s golden rule. This alignment suggests that IMT provides a practical approach to understanding nonadiabatic CT dynamics in condensed-phase systems.