Miracle-dz/UniFAR-FTUs huggingface dataset:
Single Longitudinal Mode Parity-Time Symmetric Brillouin Fiber Laser Based on Lithium Niobate Phase Modulator Sagnac Loop

A single longitudinal mode (SLM) parity-time (PT) symmetric Brillouin fiber laser (BFL) based on z-cut lithium niobate phase modulator (LN-PM) Sagnac loop with Hz level linewidth is proposed and experimentally verified. A 10 km single-mode fiber provide SBS gain, while an LN-PM Sagnac loop consisting of an LN-PM and two polarization controllers (PCs) is used to achieve PT symmetry. Two mutually linked feedback loops supporting orthogonally polarized light are created by utilizing inherent birefringence of LN waveguide from LN-PM without electrical signal modulation. One of the feedback loops experiences gain in a clockwise direction and the other loss in a counterclockwise direction. The polarization state of the stokes injected into the LN-PM is controlled by adjusting the PC, and SLM BFL can be achieved when the gain and loss are well matched and exceed the coupling coefficient to break the PT symmetry. Compared with existing BFL studies, this design does not call for frequency matching of several composite cavity structures or precise control of ultra-narrow bandwidth bandpass filters. In addition, a frequency-locking system based on Pound-Drever-Hall technology is employed to lessen the instability and external disturbances brought on by the ring cavity. In the experiment, the linewidth of PT symmetry BFL based on LN-PM Sagnac loop is 3.85 Hz, according to the measured linewidth of 77 Hz at the −20 dB power point. A 65 dB optical signal-to-noise ratio and a 43 dB maximum side mode suppression ratio are measured. Furthermore, the PT symmetry BFL's wavelength is tuned between 1550 and 1550.41 nm.
Image Sanitization in Online Social Networks: A General Framework for Breaking Robust Information Hiding

With the development of robust information hiding (RIH) approaches, secret messages can be extracted successfully from stego-data after transmission through lossy channels of online social networks (OSNs). To interrupt illegal covert communications in OSNs, some methods sanitize the uploaded images by image processing operations to destroy the hidden data that may exist. However, none of the existing methods takes the RIH methods that can resist scaling into consideration, while scaling is a common operation in OSNs. In this paper, we first propose a general framework for image sanitization in OSN platforms, which serves as a countermeasure against the RIH. By using such a framework, the secret messages embedded in the upload images can be removed and the quality of the sanitized image can be well maintained. Our framework contains two deep neural networks: Scaling-Net and SC-Net. The Scaling-Net is dedicated to the sanitization of oversized images while the SC-Net is designed for other images. To achieve a good image quality, we also propose a discriminator for adversarial training of the Scaling-Net and SC-Net. Experimental results on different datasets demonstrate that our proposed method outperforms the state-of-the-art methods. The source code and pretrained models are available at our code repository (https://github.com/zyzhu19/Image_Sanitization).
Proximal-Proximal-Gradient Method

In this paper, we present the proximal-proximal-gradient method (PPG), a novel optimization method that is simple to implement and simple to parallelize. PPG generalizes the proximal-gradient method and ADMM and is applicable to minimization problems written as a sum of many differentiable and many non-differentiable convex functions. The non-differentiable functions can be coupled. We furthermore present a related stochastic variation, which we call stochastic PPG (S-PPG). S-PPG can be interpreted as a generalization of Finito and MISO over to the sum of many coupled non-differentiable convex functions. We present many applications that can benefit from PPG and S-PPG and prove convergence for both methods. A key strength of PPG and S-PPG is, compared to existing methods, its ability to directly handle a large sum of non-differentiable non-separable functions with a constant stepsize independent of the number of functions. Such non-diminishing stepsizes allows them to be fast.
Analysis of periodically forced nonlinear Hill’s oscillator with application to a geared system

Although nonlinear systems subject to combined parametric and external excitations have been examined in some depth, very few of these investigations have addressed the influence of a mean (time‐invariant) load on the system response. In particular, the importance of the mean load effect has been highlighted in the study of whirling asymmetric shafts, where significant changes in system response and stability occur under the influence of gravity. The present paper intends to characterize the specific effect of mean load on the dynamic behavior of a Hill’s oscillator with a clearance‐type nonlinearity while also being subjected to a periodic base displacement excitation. The parametric continuation technique and method of harmonic balance would be used for this purpose. Issues discussed would include the coupling between the mean load and the dynamic response amplitude, interaction between the parametric excitation effect and the clearance nonlinearity, and comparison between time‐invariant and time‐varyin.
Numerical approximation of young-measure solutions to parabolic systems of forward-backward type

This paper is concerned with the proof of existence and numerical approximation of large-data global-in-time Young measure solutions to initial-boundaryvalue problems for multidimensional nonlinear parabolic systems of forward-backward type of the form ? tu - div(a(Du))+ Bu = F, where B ? Rmxm, Bv? v ? 0 for all v ? Rm, F is an m-component vector-function defined on a bounded open Lipschitz domain ? Rn, and a is a locally Lipschitz mapping of the form a(A)= K(A)A, where K: Rmxn ? R. The function a may have unequal lower and upper growth rates; it is not assumed to be monotone, nor is it assumed to be the gradient of a potential. We construct a numerical method for the approximate solution of problems in this class, and we prove its convergence to a Young measure solution of the system.
Effects of scattering and absorbing medium in the fluorescence conversion efficiency of physical tissue models

Auto-fluorescence spectroscopy based on spectral line shape and intensity has been in use as a promising technique for detecting varying degrees of tissue malignancy. Tissue is a turbid medium with multi-layered structure constituting of different fluorophores, absorbers and scattering molecules. Tumor progression in tissues is ac- companied by varying degrees of biochemical and morphological changes. These include changes in nuclear size and density, epithelial thickness and increase in the hemoglobin (Hb) concentration associated with changes in metabolic activity. These variations in overall tissue scattering and absorption properties in turn modulate the fluorescence spectrum emitted and derived from tissues. Estimation of fluorescence conversion efficiency in the turbid tissue needs to take into account these effects of absorption and scattering in order to be evolved as a parameter for tissue discrimination. In this study, we set to investigate the factors affecting tissue fluorescence conversion efficiency by making use of physical models of the tissue. Liquid tissue models were prepared with different concentrations of absorbing and scattering media to simulate biological tissues of various degrees of malignancy. The results indicate that emitted fluorescence from the tissue model is subjected to variations by multiple scattering events and absorption. The fluorescence conversion efficiency of the models were derived and correlated to the experimental results with possible diagnostic significance.
Inverse of multivector: Beyond p+q=5 threshold

The algorithm of finding inverse multivector (MV) in a symbolic form is of paramount importance in computational Clifford or geometric algebra (GA) $Cl_{p,q}$. The first attempts of inversion of general MV were based on matrix representation of MV basis elements. However, the complexity of such calculations grows exponentially with the dimension $n=p+q$ of $Cl_{p,q}$ algebra. The breakthrough occurred 10 years later (P. Dadbeh, 2011), after grade-negation operation was introduced. It has allowed to write down explicit and compact inverse MVs as a product of initial MV and its carefully chosen grade-negation counterparts for all GAs up to dimension $n\le5$. In this report we show that the grade-negation self-product method can be extended beyond p+q=5 threshold if, in addition, properly constructed multilinear combinations of such MV products are used. In particular, we write down compact and explicit MV inverse formulas for all $p+q=6$ algebras. For readers convenience we have also presented inverse MVs for lower algebras, $p+q\le 5$, in a form of grade negations.
Revised Stellar Temperatures for Magellanic Cloud O Supergiants from Far Ultraviolet Spectroscopic Explorer and Very Large Telescope UV-Visual Echelle Spectrograph Spectroscopy

We have undertaken quantitative analysis of four LMC and SMC O4-9.7 extreme supergiants using far-ultraviolet FUSE, ultraviolet IUE/Hubble Space Telescope, and optical Very Large Telescope UV-Visual Echelle Spectrograph spectroscopy. Extended, non-LTE model atmospheres that allow for the consistent treatment of line blanketing, developed by Hillier & Miller, are used to analyze wind and photospherics spectral features simultaneously. Using Hα to constrain mass-loss rates, He I-He II photospheric lines reveal stellar temperatures that are systematically (5-7.5 kK) and substantially (15%-20%) lower than previously derived from unblanketed, plane-parallel, non-LTE photospheric studies. We have confidence in these revisions since derived temperatures generally yield consistent fits across the entire 912-7000 Å observed spectral range. In particular, we are able to resolve the UV-optical temperature discrepancy identified for AzV 232 (O7 Iaf+) in the SMC by Fullerton and coworkers. The temperature and abundance sensitivity of far-ultraviolet, UV, and optical lines are discussed. "Of" classification criteria are directly linked to (strong) nitrogen enrichment (via N III λ4097) and (weak) carbon depletion (via C III λλ4647-4651), providing evidence for mixing of unprocessed and CNO-processed material at their stellar surfaces. Oxygen abundances are more difficult to constrain, except via O II lines in the O9.7 supergiant, for which it is also found to be somewhat depleted. Unfortunately, He/H is very difficult to determine in individual O supergiants because of uncertainties in microturbulence and the atmospheric scale height. The effect of wind clumping is also investigated, for which P V λλ1118-1128 potentially provides a useful diagnostic in O star winds, unless phosphorus can be independently demonstrated to be underabundant relative to other heavy elements. Revised stellar properties affect existing calibrations of (1) Lyman continuum photons—a factor of 2 lower for the O4 supergiant—and (2) kinetic energy released into the ISM by O supergiants. Our results also have importance for the calibration of the wind momentum-luminosity relationship for OB stars, particularly since the stars studied here are among the visually brightest OB stars in external galaxies.
Uncertainty of quantile estimators using the population index flood method

The population index flood (PIF) method is an analytical model that has been recently suggested for regional frequency analysis. In this paper, explicit equations based on Fisher's information are derived for estimating the standard error of at‐site quantile estimators for two regional PIF methods utilizing the generalized extreme value distribution with maximum likelihood estimation. These explicit equations are used to calculate the asymptotic gain in using regional frequency analysis as opposed to single site frequency analysis. Simulation experiments for different sized regions and different values of the shape parameter show that the suggested methods for estimating the standard error of at‐site quantile estimators give values close to the actual or true values. In addition, similar simulation experiments are also used to test the accuracy of a newly suggested procedure for estimating the standard errors of at‐site quantile estimators for the Hosking and Walls regional index flood method. The results of the simulations indicate that these estimated standard errors can in some cases give unreliable results. In general, this study shows that the PIF models are a useful addition to existing regional frequency analysis models. Their analytic structure, which is not present in other regional models, has important theoretical and practical implications.
Thermal analysis based on rate-equation model for VCSELs

This paper analyzes the thermal characteristics of VCSELs. The thermal model is based on rate-equations and has been implemented in ADS by using SDDs (Symbolically defined devices). The effects of the temperature on the light-current (LI) characteristics, small signal response and the transient response of a VCSEL are predicted and discussed.
Tensile strained MQW semiconductor optical amplifier

The relationship of the gain and saturation power to the strain or the number of wells is investigated for tensile strained MQW SOAs. It is proven that the saturation power decreases with increase of tensile strain, and that the gain increases with increase of the number of wells but the saturation power decreases. Next we fabricated two SOAs that are polarization-insensitive: one has 5 wells with -0.45% strain; and the other has 7 wells with -0.55% strain. The optical gains are 10.0 dB and 14.5 dB, the saturation power are 9.0 dBm and 6.5 dBm, respectively. The characteristics of signal power of non-degenerate four-wave mixing (NDFWM) are investigated using these SOAs. It is suggested that the SOA of larger gain generates larger signal power when the input power is small, while the SOA of larger saturation power generates larger signal power when the input power is around the SOA saturation power.
Rules mining on hybrid electric vehicle consumer complaint database

Abstract The hybrid electric vehicle (HEV) is a critical transportation disruptive technology that is expected to be widely adopted in the current and future marketplace. Many nations are promoting the success of HEVs. As the technologies and designs of these vehicles are significantly different from conventional vehicles, it is also important to understand the technical and body-related issues associated with these vehicles. This study used the National Highway Traffic Safety Administration’s vehicle owner’s complaint database to explore the potential issues associated with HEVs. The acquired dataset was divided into two groups based on their involvement in traffic crashes. The study applied association rule mining and text mining methods to analyze vehicle consumer complaint data. The results of association rule mining showed a significant association between hybrid electric all-wheel-drive vehicles manufactured between 2010 and 2021 that do not have anti-lock brakes and cruise control in the crash-related vehicle complaints dataset. Non-HEV vehicles, manufactured between 1992 and 1999, with cruise control and anti-braking systems as well as 5-10 cylinders, appeared frequently in the crash-related complaint dataset. Mileage-related issues and comparatively older HEVs (2000-2009) are dominant in non-crash-related data. The results from the text mining method show that brakes, mileage, failure, and crash are key features for consumer complaints related to crashes and brakes, battery, power, and recall are the key features for consumer complaints not related to crashes. The sentiment analysis results show slightly higher negative sentiments in complaint reports associated with crashes. The findings of this study can provide some insights into this unexplored research area.
Pemodelan Harga Minyak Sayuran Menggunakan Analisis Regresi Linear Berganda

Kajian ini merupakan penerokaan awal terhadap data harga-harga minyak yang berada di pasaran dunia. Lima harga minyak yang dipertimbangkan adalah harga minyak kelapa sawit mentah (CPO), harga minyak kacang soya (SBO), harga minyak kelapa (CNO), harga minyak isirong sawit (KPO) dan harga minyak biji sawi (RSO). Data bulanan harga-harga minyak dari tahun 1983 hingga tahun 2000 yang melibatkan 216 cerapan telah dianalisis. Hasil analisis regresi berganda mendapati nilai R2 adalah 0.887 yang bermaksud bahawa sebanyak 88.7 peratus ubahan dalam harga minyak sawit mentah dapat diterangkan secara bererti oleh pembolehubah tak bersandar RSO, KPO dan CNO. Hasil ujian-t juga menunjukkan bahawa setiap pekali bagi pembolehubah tak bersandar adalah bererti pada aras keertian satu peratus. Diagnosis model juga telah dilakukan dan didapati wujud masalah multikolineariti dan autokorelasi dalam data yang memerlukan penelitian yang lebih lanjut lagi. Katakunci: Harga minyak sawit mentah; regresi berganda; multikolineriti. This study focused on application of multiple regression in modeling vegetable oil prices. Five vegetable oil prices, namely CPO, SBO, CNO, PKO, and RSO have been analysed using monthly oil price data from year 2000. We found that multiple linear regression gave the $R^2$ value of 0.887, meaning 88.7\% of variance in CPO price could be explained by RSO, PKO, and CNO. The $t$-test showed that the parameter estimates is significant at one percent level. This study concluded that multicollinearity and autocorrelation were detected inmuliple linear regression and are needed to be considered in further research. Keywords: Crude palm oil price; multiple regression; multicollinearity.
Design and Analysis of Broadband Power Delivery Network Noise Absorber for Parallel-Plate Mode Suppression

In this article, a broadband power delivery network (PDN) noise absorber with its 90%-absorption band from 4 to 7.5 GHz is proposed to suppress parallel-plate modes. Due to the ever-increasing switching speed of integrated circuits (ICs) nowadays, a few millimeters separating a chip and the conventional reflective filters may induce significant power noises and cause serious radio frequency interference (RFI) and electromagnetic interference (EMI) problems. In this scenario, PDN noise absorbers can prevent power noises from both reflecting and transmitting, thus avoiding cavity resonances, providing a clean and stable power supply, and achieving almost zero radiation. Four cases were compared to verify all these advantages of the PDN noise absorbers. For conducted noises around 6 GHz, the self-impedance peak is suppressed by 86.9% at the noise source end and the insertion loss is almost the same level at the transmitted end when compared with the case of two rings of the reflective filters. Furthermore, almost 100% of the radiative noises are cleared away by the proposed PDN noise absorbers.
Elevation Gradients Limit the Antiphase Trend in Vegetation and Its Climate Response in Arid Central Asia

Vegetation in arid central Asia (ACA) has been experiencing significant changes due to substantial warming and humidification since the 1980s. These changes are inhomogeneous due to the ecological vulnerability and topographic complexity of ACA. However, the heterogeneity of vegetation changes has received limited attention in the literature, which has focused more on the region’s overall general features. Thus, this paper analyzes the regional heterogeneity of vegetation changes during the growing season in ACA and further explores their underlying drivers. The results reveal an antiphase trend of vegetation, with an increase in eastern ACA and a decrease in western ACA. This antiphase pattern is primarily constrained by the divergent hydrothermal and climatic contexts of different elevation gradients. At elevations higher than 300 m (in the eastern ACA), increased growing season precipitation dominates vegetation greening. Conversely, vegetation at elevations lower than 300 m (in western ACA) is influenced by growing season soil water, which is driven by winter precipitation (pre-growing season precipitation). Additionally, the temperature could indirectly impact vegetation trends by altering precipitation, soil water, glaciers, snow cover, and runoff. Our findings have implications for restoring the ecosystem and sustainable development in ACA.
Measurement of thickness and refractive index using femtosecond and terahertz pulses

We report a simple method to measure the thickness and refractive index of parallel-plane samples simultaneously using femtosecond and terahertz pulses. The time-of-flight measurements of the pulses with and without a sample are exploited to determine the thickness and refractive index of the sample. The accuracy in thickness measurement using femtosecond pulses is 2–3 μm where refractive index can be measured with an accuracy up to three decimal points. The accuracy and lower limit of thickness measurement using terahertz pulses is also improved.
Resource Scheduling for Intelligent Reflecting Surface-Assisted Full-Duplex Wireless-Powered Communication Networks With Phase Errors

Intelligent reflecting surface (IRS) is envisioned as a promising technique to improve the performance of full-duplex wireless-powered communication networks (FD-WPCNs). This article investigates the joint phase beamforming design and resource management for IRS-assisted FD-WPCNs, where multiple wireless devices (WDs) can harvest downlink radio-frequency energy and transmit uplink information to the hybrid access point (HAP) over the same band with the aid of IRS. We first formulate a total transmission time minimization problem subject to the minimum transmit rate and energy causality constraints of WDs. In particular, the random phase error of IRS is integrated into our optimization model. Furthermore, we develop an alternating optimization method to obtain the optimal solution of the formulated nonconvex problem by iteratively solving two subproblems. For the phase beamforming optimization subproblem, we first convert the random phase errors to a deterministic expression, and then utilize the successive convex approximation method to solve the phase beamforming optimization problem. For the transmit power and time-slot allocation subproblem, the optimal transmit power of WDs is derived in closed-form expressions, and the approximation method and variable substitution technique are adopted to obtain the optimal time-slot allocation and transmit power of HAP. Finally, numerical results are provided to evaluate the performance of our proposed method and reveal the benefits introduced by the IRS technique as compared to benchmark methods.
An Optimized Speckle Noise Reduction Filter For Ultrasound Images using Anisotropic Diffusion Technique

Noise is possibly the most annoying problem in the ﬁeld of image processing. In medical image or ultrasound image processing the speckle noise is arises with a major difficulty. Eliminating such noise is an important preprocessing task. For acquiring a better performance, an optimized anisotropic diffusion techniques for ultrasound images are presented in this paper. It’s a new method for denoising the image without blurring the frontiers between different regions. This method is based on the differentiation of the diffusion in the direction of the gradient. For quantifying the performance we calculate the ratio of mean grey level, the signal to noise ratio, the peak signal to noise ratio, the root mean square error, image fidelity and the structural content. This method gives a better result with comparison to existing Perona–Malik anisotropic diffusion method.