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2. CLASS GROUPS IN CYCLIC ℓ-EXTENSIONS: COMMENTS ON A PAPER BY G. CORNELL
- Author
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ROSEN, MICHAEL
- Published
- 2014
3. Rectifications to the Papers Sets of Uniqueness and Sets of Multiplicity, I and II
- Author
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Salem, R.
- Published
- 1948
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4. Generalized Limits in General Analysis: Second Paper
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Moore, Charles N.
- Published
- 1923
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5. Generalized Limits in General Analysis, First Paper
- Author
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Moore, Charles N.
- Published
- 1922
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6. Generalization of Certain Theorems of Bohl, [Second Paper]
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Murray, F. H.
- Published
- 1927
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7. α-淀粉酶处理废纸浆降解淀粉类 有机物及净化浆料研究.
- Author
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冯琨, 孔话峥, 王燕燕, 赵梦醒, and 刘廷志
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WASTE paper ,PAPER pulp ,ABSOLUTE value ,SEWAGE ,ZETA potential - Abstract
Copyright of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2020
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- View/download PDF
8. The role of the fiber and the bond in the hygroexpansion and curl of thin freely dried paper sheets.
- Author
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Brandberg, August, Motamedian, Hamid Reza, Kulachenko, Artem, and Hirn, Ulrich
- Subjects
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ABSOLUTE value , *FIBERS - Abstract
A computationally efficient method to study the in-plane and out-of-plane dimensional instability of thin paper sheets under the influence of moisture changes is presented. The method explicitly resolves the bonded and the free segments of fibers in the sheet, capturing the effect of anisotropic hygroexpansion at the fiber level. The method is verified against a volumetric model. The importance of longitudinal fiber hygroexpansion is demonstrated in spite of the absolute value of longitudinal hygroexpansion being an order of magnitude lower than the transverse hygroexpansion component. Finally, the method is used to demonstrate the formation of macroscopic sheet curl due to a moisture gradient in structurally uniform sheets in the absence of viscoelastic or plastic constitutive behavior and through-thickness residual stress profiles. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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9. Some Remarks on Montel's Paper concerning Upper Limit of Absolute Values of Roots of Algebraic Equations
- Author
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Tôya, Tikara
- Published
- 1933
10. Allelopathic Effects of Cedrus deodara Needle Extracts on Seed Germination and Early Growth of Three Turfgrasses.
- Author
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Menghong HU, Xun LYU, Man SUN, Baoquan ZHANG, and Yuan LIU
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ORNAMENTAL plants ,GERMINATION ,TURFGRASSES ,WHITE clover ,ABSOLUTE value ,WATER purification ,FILTER paper - Abstract
This study was conducted to provide reference for plant landscaping, optimization of planting structure and rational allocation of species in Cedrus deodcua gardens. [Methods] With three common garden plants in northern China, Trifolium repens L, Poa pralensis L and Trifolium pralense L, as receptors, the effects of four concentrations ( 0.025, 0. 05, 0.075 and 0.10 g/ml) of C. deodara needle extract on seed germination and early seedling growth of the three turf grasses were studied by the Petri dish filter paper method, using a clear water treatment ( 0 g/ml) as control check (CK). Data were subjected to analysis of variance ( ANOVA) and multiple comparisons (Duncan) using SPSS16. 0. [Results] Different concentrations of C. deodcua needle extract had significant inhibitory effects on seed germination, radicle and seedling height growth of T. repens, T. pratense and P. pratensis ( P < 0.05 ), and the inhibitory effects increased with the increase of concentration. When the concentration reached 0. 075 g/ ml, seed germination and seedling growth of T. repens stopped, and radicle and seedling growth of T. pratense and P. pralensis also stopped. When the concentration was equal to 0.10 g/ ml, germination of T. pralense and P. pralensis seeds was inhibited, and the absolute values of allelopathic index was the largest, that is, the inhibitory effects were the largest. And with the increase of concentration, the absolute value of synthetical allelopathic index also increased. The extract of C. deodcua needles contained main allelochemicals leading to the scarcity of understory vegetation. [Conclusions] This study provides a theoretical basis for reasonable garden plant configuration during C. deodara greening and garden landscaping. [ABSTRACT FROM AUTHOR]
- Published
- 2022
11. Non-covalently cationized nanocellulose from hemp: Kinetics, key properties, and paper strengthening.
- Author
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Aguado, Roberto, Tarrés, Quim, Mutjé, Pere, Pèlach, M. Àngels, and Delgado-Aguilar, Marc
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SURFACE charges , *HEMP , *WOOD-pulp , *ADSORPTION kinetics , *ABSOLUTE value , *WOOD chemistry , *HYDROXYL group , *LIGNIN structure - Abstract
Cationic cellulose, despite its long history, has yet to find a place in the paper industry. However, recent research is evaluating the potential of its nanoscale forms. Likewise, the processes of Western manufacturers are optimized for wood pulps, relegating non-wood crops to specific products that, as also proposed by current research, could include nanocellulose. We combined these trends with the existing knowledge of the strong adsorption of poly(diallyldimethylammonium chloride) (polyDADMAC) on cellulosic fibers, which can be deemed a non-covalent kind of cationization. For that, polyDADMAC was first anchored to refined hemp pulps, under conditions that allowed the deprotonation of the primary hydroxyl groups of cellulose. The fiber surface remained positively-charged even after thoroughly washing the samples, owing not only to the small proportions of acidic hemicelluloses and lignin, but also to stable ion-dipole interactions. This non-covalent cationization was found to follow pseudo-second order kinetics, indicating that diffusion through the fiber was the rate-controlling step. PolyDADMAC-containing fibers were then fibrillated by high-pressure homogenization. The surface charge of cationic nanocellulose was greater than that of the starting fibers, as the specific surface area increased. Nonetheless, polyDADMAC caused agglomeration of fibrils to a certain extent. As a drawback, when applied in papermaking, cationic nanocellulose lowered air permeability to a lesser extent than non-cationized nanofibers. As an advantage, the tensile index increased by up to 57% in the absence of any retention agent. • Adsorption of polyDADMAC to hemp pulp fibers follows pseudo-second order kinetics. • Both refining and fibrillation increase the absolute value of the surface charge. • Strong binding of polyDADMAC: ionic in alkaline media, ion-dipole after neutralization. • The resulting nanofibers improve paper strength without the need of retention aids. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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12. Complex situations, guidelines, high scientific value papers and the real world: a crucial combination.
- Author
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Campanelli, Giampiero
- Subjects
- *
SCIENTIFIC literature , *HERNIA surgery , *ABDOMINAL wall , *ABSOLUTE value - Abstract
This document discusses the importance of a scientific approach in the field of abdominal wall surgery. It emphasizes the need for a combination of factors, including personal experience, guidelines, and analysis of scientific literature, in order to provide patients with the best possible care. The document also highlights the complexity of the field and the value of research in addressing challenging situations. This special issue of the journal Hernia, guest edited by international experts, aims to provide surgeons with valuable insights and support in their daily practice. [Extracted from the article]
- Published
- 2024
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13. A new complex mapping method of neural networks used in sound source localization.
- Author
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Jian, Zeming, Hu, Junhao, Nie, Lei, and Liu, Mengran
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ACOUSTIC localization ,CONVOLUTIONAL neural networks ,LOCALIZATION (Mathematics) ,ABSOLUTE value ,SMART homes - Abstract
Sound source localization has a wide range of application prospects in many fields, such as smart home and audio monitoring. Traditional methods are difficult to achieve accurate location in the face of multi-path reflection, reverberation, and ambient noise. In this paper, a complex mapping conversion method for sound source location is proposed. By using complex-valued convolutional neural networks to fuse the amplitude and phase information of the data, a more accurate and comprehensive analysis can be carried out to improve its robustness and realize the accurate location of the sound source. The sound source location method based on complex-valued convolutional neural networks is studied, and the complex mapping principle is analyzed. Simulation and experimental studies were carried out, and the results of simulation and experiment are basically consistent. In the experiment, the positioning accuracy of the complex mapping method is 9.49% higher than that of the absolute value method and 15.81% higher than that of the phase angle method. In addition, its localization success rate, respectively, increased by 4.9% and 8.6% compared to two other methods. This paper opens up a new way for the application of complex-valued convolutional neural networks in sound source localization. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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14. Evaluation of Landslide Susceptibility in Tekes County, Yili Prefecture Based on the Information Quantity Method.
- Author
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Cao, Xiaohong, Wu, Bin, Shang, Yanjun, Wang, Weizhong, Xu, Tao, Li, Qiaoxue, and Meng, He
- Subjects
AUTOMATIC control systems ,ABSOLUTE value ,LANDSLIDES ,GEOLOGICAL formations ,STATISTICAL correlation - Abstract
In order to scientifically and rationally evaluate the susceptibility to landslide hazards in Tekes County, Yili State. This paper takes Tekes County in Xinjiang as an example, on the basis of a comprehensive analysis of the regional geological environment conditions and the distribution pattern and formation conditions of geological disasters, using the data of geological disaster points (landslide center points), and through the correlation matrix calculation of the evaluation factors, the nine evaluation factors with larger absolute values of correlation coefficients were determined to construct the evaluation system of the susceptibility to landslide geological hazards in Tekesi County. Combining the information quantity method and the entropy value method, using the weights determined by the entropy value method, the information quantity method is used to calculate the information quantity value of each factor within the factor, calculate the susceptibility index of landslide geological disasters within the territory of Tekes County, and then carry out the landslide susceptibility evaluation. The susceptibility of landslide disasters was evaluated by ArcGIS. The results show that the landslide disaster susceptibility level in Tekes County can be divided into four levels: high susceptibility, medium susceptibility, low susceptibility, and not susceptible, with areas of 491.3276 km
2 , 1181.5171 km2 , 1674.7609 km2 and 5295.2976 km2 accounting for 5.68%, 13.67%, 19.38% and 61.27% of the total area of Tex County, respectively. The AUC number obtained by the success curve method (ROC) is 0.8736, reflecting the evaluation accuracy of 87.36%, indicating that the model method used in this paper is effective. The results are expected to provide practical data support for landslide disaster control in Tekes County and provide a reference for geological disaster monitoring, early warning and engineering prevention and control deployment in Yili Valley. [ABSTRACT FROM AUTHOR]- Published
- 2024
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15. 猪肉价格波动的影响因素分析及预警机制研究 ----基于山东省猪肉价格的实证分析.
- Author
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周玉兰, 王官娟, and 李爱爱
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PRICE fluctuations ,PRICES ,SUPPLY & demand ,VALUE (Economics) ,ABSOLUTE value ,PORK products - Abstract
Copyright of Agricultural Outlook (1673-3908) is the property of Institute of Agricultural Information, Chinese Academy of Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2024
16. A new two-step iterative technique for efficiently solving absolute value equations.
- Author
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Gul, Nisar, Chen, Haibo, Iqbal, Javed, and Shah, Rasool
- Subjects
ABSOLUTE value ,EQUATIONS - Abstract
Purpose: This work presents a new two-step iterative technique for solving absolute value equations. The developed technique is valuable and effective for solving the absolute value equation. Various examples are given to demonstrate the accuracy and efficacy of the suggested technique. Design/methodology/approach: In this paper, we present a new two-step iterative technique for solving absolute value equations. This technique is very straightforward, and due to the simplicity of this approach, it can be used to solve large systems with great effectiveness. Moreover, under certain assumptions, we examine the convergence of the proposed method using various theorems. Numerical outcomes are conducted to present the feasibility of the proposed technique. Findings: This paper gives numerical experiments on how to solve a system of absolute value equations. Originality/value: Nowadays, two-step approaches are very popular for solving equations (1). For solving AVEs, Liu in Shams (2021), Ning and Zhou (2015) demonstrated two-step iterative approaches. Moosaei et al. (2015) introduced a novel approach that utilizes a generalized Newton's approach and Simpson's rule to solve AVEs. Zainali and Lotfi (2018) presented a two-step Newton technique for AVEs that converges linearly. Feng and Liu (2016) have proposed minimization approaches for AVEs and presented their convergence under specific circumstances. Khan et al. (2023), suggested a nonlinear CSCS-like technique and a Picard-CSCS approach. Based on the benefits and drawbacks of the previously mentioned methods, we will provide a two-step iterative approach to efficiently solve equation (1). The numerical results show that our proposed technique converges rapidly and provides a more accurate solution. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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17. Complex modal analysis of structural vibration and acoustic radiation of plates.
- Author
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Wei, Lai and Li, Sheng
- Subjects
ACOUSTIC radiation ,STRUCTURAL dynamics ,ACOUSTIC vibrations ,EIGENVECTORS ,MODAL analysis ,ABSOLUTE value ,COUPLINGS (Gearing) - Abstract
Inhomogeneous damping distribution leads to the occurrence of complex modes of structures. Complex modes' vibration and acoustic radiation characteristics are different from real modes. This paper studies the complex modal characteristics of inhomogeneously damped plates for forced vibration. We used the state space method to obtain the complex eigenvalues and eigenvectors of the vibration system and calculated the relationship between modal coordinates and frequency under unit force. The results show that the absolute values of the modal coordinates of two conjugate complex eigenvectors are different, and the structure's vibration is dominated by the eigenvectors corresponding to eigenvalues with positive imaginary parts near natural frequencies. When investigating the structural sound radiation in the vibration mode space, each mode's acoustic radiation is not independent but coupled with each other. The influence of the coupling between complex modes on the calculation results of the acoustic radiation power of the plate is studied in this paper. The results show that the coupling effect between modes cannot be ignored when calculating the acoustic radiation power based on complex modes. Finally, the error of calculating acoustic power using the decoupling approximation instead of the complex mode method is analyzed. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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- View/download PDF
18. Regulation Fair Disclosure and Earnings Information: Market, Analyst, and Corporate Responses
- Author
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Bailey, Warren, Li, Haitao, Mao, Connie X., and Zhong, Rui
- Published
- 2003
19. New Methods of Series Expansions between Three Anomalies.
- Author
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Zhao, Dongfang, Li, Houpu, Bian, Shaofeng, Chen, Yongbing, and Li, Wenkui
- Subjects
EXTREME value theory ,FOURIER series ,KEPLER'S equation ,ABSOLUTE value ,POWER series - Abstract
The calculation of satellite orbit involves some very complex formula derivations and expansions, which are very difficult to manually derive and prone to errors. And the efficiency of manual derivation is not high. We can use computer algebra systems to derive complex formulas related to satellite orbits. This can avoid some of the drawbacks of manual derivation and significantly improve computational efficiency and accuracy. In the past, the relationship among three anomalies was generally represented in the form of a trigonometric series with the first eccentricity e as the parameter. In this paper, the trigonometric series with the parameter m = 1 − 1 − e 2 e is used, as determined by the Lagrange conjugate series. We can use the formula of the Lagrange conjugate series to derive the relationship between the true anomaly and elliptic anomaly. And the relationship between the elliptic anomaly and the mean anomaly is derived by using the symbolic iteration method. In this research paper, we calculated the accuracy of the trigonometric series expansion among three types of anomalies at the first eccentricity e equal to values of 0.01, 0.1, and 0.2. The calculation results indicate that the accuracy of the trigonometric series expansion with m as the parameter is better than 10
−5 . Moreover, in some cases, the trigonometric series expansion among the three anomalies with m as a parameter is simpler in form than the expansion expressed with parameter e. This paper also derived and calculated the symbolic expressions and extreme values of the difference among three anomalies and expressed the extreme values of the difference in the form of a power series of e. It can be seen that the extreme value increases with the increase in eccentricity e. And the absolute values of the extreme value of the difference between the elliptic anomaly and the mean anomaly, the true anomaly and the elliptic anomaly, and the true anomaly and the mean anomaly increase in this order. When the eccentricity is small, the absolute value of the extreme value of the difference between the true anomaly and the mean anomaly is about twice as large as the elliptic anomaly and the mean anomaly and the true anomaly and the mean anomaly. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
20. Uniqueness and stability for the solution of a nonlinear least squares problem.
- Author
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Huang, Meng and Xu, Zhiqiang
- Subjects
CONVEX sets ,ABSOLUTE value ,LEAST squares - Abstract
In this paper, we focus on the nonlinear least squares problem: \min _{{\boldsymbol {x}}\in \mathbb {H}^d}\|\lvert A{\boldsymbol {x}}\rvert -{\boldsymbol {b}}\| where A\in \mathbb {H}^{m\times d}, {\boldsymbol {b}}\in \mathbb {R}^m with \mathbb {H}\in \left \{\mathbb {R},\mathbb {C}\right \} and consider the uniqueness and stability of solutions. This problem arises in applications such as phase retrieval and absolute value rectification neural networks. While several results have been developed to characterize the uniqueness and stability of solutions when {\boldsymbol {b}}=\lvert A{\boldsymbol {x}}_0\rvert for some {\boldsymbol {x}}_0\in \mathbb {H}^d, no existing results address the case where {\boldsymbol {b}} is arbitrary. In this paper, we investigate the uniqueness and stability of solutions for the more general case where {\boldsymbol {b}} is not necessarily equal to \lvert A{\boldsymbol {x}}_0\rvert for any {\boldsymbol {x}}_0\in \mathbb {H}^d. We prove that for any matrix A\in \mathbb {H}^{m\times d}, there is always a vector {\boldsymbol {b}}\in \mathbb {R}^m for which the solution to the nonlinear least squares problem is not unique. However, we show that such "bad" vectors {\boldsymbol {b}} are negligible in practice; specifically, if {\boldsymbol {b}}\in \mathbb {R}_{ }^m does not lie in some measure zero set, then the solution is unique. Furthermore, we establish certain conditions under which the solution is guaranteed to be unique. Regarding the stability of solutions, we prove that the solution is not uniformly stable. However, if we restrict the vectors {\boldsymbol {b}} to a convex set where the solution to the least squares problem is unique, then the solution becomes stable. To the best of our knowledge, our results represent the first theoretical results of the uniqueness and stability of solutions for the nonlinear least squares problem. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
21. Design and Use of Deep Confidence Network Based on Crayfish Optimization Algorithm in Automatic Assessment Method of Hearing Effectiveness.
- Author
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Ying Cheng
- Subjects
OPTIMIZATION algorithms ,CRAYFISH ,FEATURE extraction ,ABSOLUTE value ,CONFIDENCE - Abstract
INTRODCTION: Listening strategy analysis and assessment not only need objective and fair sound listening strategy analysis, but also need high-precision and high real-time assessment model, and even more need in-depth analysis and feature extraction of the influencing factors of listening assessment. OBJECTIVES: To address the problems of current automatic assessment methods, such as non-specific application, poor generalization, low assessment accuracy, and poor real-time performance. METHODS: This paper proposes an automatic assessment method based on a deep confidence network based on crawfish optimization algorithm. First, the multi-dimensional listening strategy evaluation system is constructed by analyzing the listening improvement strategy; then, the depth confidence network is improved by the crayfish optimization algorithm to construct the automatic evaluation model; finally, through the analysis of simulation experiments. RESLUTS: The proposed method improves the evaluation accuracy, robustness, and real-time performance. The absolute value of the relative error of the automatic evaluation value of the proposed method is controlled in the range of 0.011, and the evaluation time is less than 0.005 s. The method is based on a deep confidence network based on the crayfish optimization algorithm. CONCLUSION: The problems of non-specific application of automated assessment methods, poor generalization, low assessment accuracy, and poor real-time performance are addressed. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
22. Time-varying discrete cosine transform based on shaping regularization and its application in seismic data analysis.
- Author
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Zhu, Zhaolin, Wu, Guoning, Gu, Yaxin, Huang, Jinliang, Chen, Zhihao, and Lu, Haotian
- Subjects
DISCRETE cosine transforms ,RADON transforms ,DATA analysis ,COSINE function ,ABSOLUTE value ,DISCRETE wavelet transforms ,SIGNAL processing ,LINEAR systems - Abstract
The discrete cosine transform is a commonly used technique in the field of signal processing that employs cosine basis functions for signal analysis. Traditionally, the regression coefficients of the cosine basis functions are solely based on frequency information. This paper extends the regression coefficients associated with the cosine basis functions to take into account both frequency and time information, not just frequency information alone. This modification results in an ill-posed linear system, which requires regularization to prevent overfitting. To address this, this paper uses shaping regularization, a technique used to stabilize ill-posed problems. By doing so, the absolute values of these extended coefficients, now exhibiting variations in both frequency and time domains, are defined as the time–frequency distribution of that input signal. The numerical experiments conducted to validate this approach demonstrate that the proposed method yields a commendable time–frequency resolution. Consequently, it proves valuable for interpreting seismic data, showcasing its potential for applications in this field. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
23. Wind tunnel test on low-rise buildings influenced by hillside height in typical mountain terrain.
- Author
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Zhong, Min, Lin, Minghui, Zhou, Zhanxue, Li, Zhengnong, Lu, Junyu, and Xu, Fen
- Subjects
WIND tunnel testing ,TYPHOONS ,WIND pressure ,ABSOLUTE value ,BUILDING stones ,MODELS & modelmaking - Abstract
Hills and mountain fields have a high proportion in coastal areas around the world. Especially in China, lots of low-rise buildings are in complex mountain terrain. Compared with the flat topography under typhoons, due to the change caused by complex topography, the damage ratio of low-rise buildings is much larger. This paper investigates the wind pressure distribution in three different configurations of typical mountain terrain on low-rise buildings in coastal areas by wind tunnel tests. At the same time, the results are compared with the wind pressure distribution of low-rise buildings without surrounding structures. The variation of the average pressure coefficient and shape coefficient with the change of hillside height under a wind attack angle of 0° and the trends of average wind pressure coefficients of a low-rise building under wind attack angles of 0° – 90° are studied. The results show that the distribution of pressure in low buildings is significantly affected by the height of the mountain. When the hillside height is half of the scale physical model, the influence coefficient from the mountain to each surface of the whole building is within 50%. When the hillside height is four times that of the model, the influence factor from the mountain to each surface of the whole building is obvious and is most significantly influenced by the leeward roof. The mean design criteria of the low-rise building, such as windward midline, leeward roof, and windward roof in these three typical mountain terrains, should be designed for their higher absolute value of the average pressure coefficient. The mean pressure coefficient under different wind angles and mountain environments has a significant relationship. The most unfavorable wind angle of wind load calculations should be considered when designing low-rise buildings. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
24. Evaluation of a Condition Monitoring Algorithm for Early Bearing Fault Detection.
- Author
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Gruber, Hannes, Fuchs, Anna, and Bader, Michael
- Subjects
ROLLER bearings ,BREAKDOWNS (Machinery) ,OUTLIER detection ,TRACKING algorithms ,FAILED states ,ALGORITHMS ,ABSOLUTE value ,FAST Fourier transforms - Abstract
Roller bearings are critical components in various mechanical systems, and the timely detection of potential failures is essential for preventing costly downtimes and avoiding substantial machinery breakdown. This research focuses on finding and verifying a robust method that can detect failures early, without creating false positive failure states. Therefore, this paper introduces a novel algorithm for the early detection of roller bearing failures, particularly tailored to high-precision bearings and automotive test bed systems. The featured method (AFI—Advanced Failure Indicator) utilizes the Fast Fourier Transform (FFT) of wideband accelerometers to calculate the spectral content of vibration signals emitted by roller bearings. By calculating the frequency bands and tracking the movement of these bands within the spectra, the method provides an indicator of the machinery's health, mainly focusing on the early stages of bearing failure. The calculated channel can be used as a trend indicator, enabling the method to identify subtle deviations associated with impending failures. The AFI algorithm incorporates a non-static limit through moving average calculations and volatility analysis methods to determine critical changes in the signal. This thresholding mechanism ensures the algorithm's responsiveness to variations in operating conditions and environmental factors, contributing to its robustness in diverse industrial settings. Further refinement was achieved through an outlier detection filter, which reduces false positives and enhances the algorithm's accuracy in identifying genuine deviations from the normal operational state. To benchmark the developed algorithm, it was compared with three industry-standard algorithms: VRMS calculations per ISO 10813-3, Mean Absolute Value of Extremums (MAVE), and Envelope Frequency Band (EFB). This comparative analysis aimed to evaluate the efficacy of the novel algorithm against the established methods in the field, providing valuable insights into its potential advantages and limitations. In summary, this paper presents an innovative algorithm for the early detection of roller bearing failures, leveraging FFT-based spectral analysis, trend monitoring, adaptive thresholding, and outlier detection. Its ability to confirm the first failure state underscores the algorithm's effectiveness. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
25. A new efficient two-step iterative method for solving absolute value equations.
- Author
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Khan, Alamgir, Iqbal, Javed, and Shah, Rasool
- Subjects
ABSOLUTE value ,NONLINEAR equations ,FINITE difference method ,EQUATIONS - Abstract
Purpose: This study presents a two-step numerical iteration method specifically designed to solve absolute value equations. The proposed method is valuable and efficient for solving absolute value equations. Several numerical examples were taken to demonstrate the accuracy and efficiency of the proposed method. Design/methodology/approach: We present a two-step numerical iteration method for solving absolute value equations. Our two-step method consists of a predictor-corrector technique. The new method uses the generalized Newton method as the predictor step. The four-point open Newton-Cotes formula is considered the corrector step. The convergence of the proposed method is discussed in detail. This new method is highly effective for solving large systems due to its simplicity and effectiveness. We consider the beam equation, using the finite difference method to transform it into a system of absolute value equations, and then solve it using the proposed method. Findings: The paper provides empirical insights into how to solve a system of absolute value equations. Originality/value: This paper fulfills an identified need to study absolute value equations. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
26. Proof of the Kresch-Tamvakis conjecture.
- Author
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Caughman, John S. and Terada, Taiyo S.
- Subjects
LOGICAL prediction ,INTEGERS ,MATHEMATICS ,ABSOLUTE value - Abstract
In this paper we resolve a conjecture of Kresch and Tamvakis [Duke Math. J. 110 (2001), pp. 359–376]. Our result is the following. Theorem : For any positive integer D and any integers i,j (0\leq i,j \leq D), \; the absolute value of the following hypergeometric series is at most 1: \begin{equation*} {_4F_3} \left [ \begin {array}{c} -i, \; i+1, \; -j, \; j+1 \\ 1, \; D+2, \; -D \end{array} ; 1 \right ]. \end{equation*} To prove this theorem, we use the Biedenharn-Elliott identity, the theory of Leonard pairs, and the Perron-Frobenius theorem. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
27. A novel method for gear gravimetric wear prediction based on improved particle swarm optimization and non-stationary random process probability distribution fitting.
- Author
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Chen, Cheng and Wang, Honghua
- Subjects
PARTICLE swarm optimization ,DISTRIBUTION (Probability theory) ,STOCHASTIC processes ,ABSOLUTE value ,STATIONARY processes ,GAUSSIAN sums - Abstract
Purpose: Stimulated by previous reference, which proposed making straight line of regression to test gear gravimetric wear loss sequence distribution, this paper aims to propose using straight line of regression to fit gear gravimetric wear loss sequence based on stationary random process suppose. Faced to that the stationary random sequence suppose had not been proved by previous reference, and that prediction did not present high precision, this paper proposes a method of fitting non-stationary random process probability distribution function. Design/methodology/approach: Firstly, this paper proposes using weighted sum of Gauss items to fit zero-step approximate probability density. Secondly, for the beginning, this paper uses the method with few Gauss items under low precision. With the amount of points increasing, this paper uses more Gauss items under higher precision, and some Gauss items and some former points are deleted under precision condition. Thirdly, for particle swarm optimization with constraint problem, this paper proposed improved method, and the stop condition is under precision condition. Findings: In experiment data analysis section, gear wear loss prediction is done by the method proposed by this paper. Compared with the method based on the stationary random sequence suppose by prediction relative error, the method proposed by this paper lowers the relative error whose absolute values are more than 5%, except when the current point sequence number is 2, and retains the relative error, whose absolute values are lower than 5%, still lower than 5%. Originality/value: Finally, the method proposed by this paper based on non-stationary random sequence suppose is proved to be the better method in gear gravimetric wear loss prediction. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
28. Research on the Impact of Atmospheric Self-Purification Capacity on Environmental Pollution: Based on the Threshold Effect of Environmental Regulation.
- Author
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Zhou, Jingkun, Zhao, Xiao, and Yin, Ting
- Subjects
POLLUTION ,ENVIRONMENTAL regulations ,AIR pollution ,ABSOLUTE value ,STATISTICS ,POLLUTION prevention - Abstract
In China, Hebei Province and Guangdong Province have many pollution-intensive industries; yet Hebei suffers more serious atmospheric or environmental pollution than Guangdong. To explain the phenomenon, this paper chooses the statistical data of 286 prefecture-level cities in the Chinese mainland from 2005 to 2018 and empirically tests the spatial effect and threshold characteristics of atmospheric self-purification capacity on environmental pollution by using the spatial autoregression model (SAR), spatial Durbin model (SDM), and panel threshold model. As evinced, the local atmospheric self-purification capacity has a significant inhibitory effect on environmental pollution, and the absolute value of the direct effect coefficient reaches 1.337. Simultaneously, atmospheric self-purification capacity has a threshold effect on environmental pollution. The threshold value of environmental regulation as a threshold variable is 11.6349. This means that when the level of environmental regulation proves higher than 11.6349, it attenuates the inhibitory effect of the atmospheric self-purification capacity on environmental pollution. As the heterogeneity research unveils, atmospheric self-purification capacities in various regions form a significant correlation with environmental pollution. This paper suggests that local governments should strengthen environmental regulation and construct an inter-regional joint prevention and control system for atmospheric-pollution governance to enhance the atmospheric self-purification capacity. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
29. Return of the NPLs to the Bright Side: Which Unlikely to Pay Firms are More Likely to Pay?
- Author
-
Affinito, Massimiliano and Meucci, Giorgio
- Subjects
NONPERFORMING loans ,BANK loans ,ABSOLUTE value ,BUSINESS size ,BUSINESS enterprises ,ENDOWMENTS ,DEBTOR & creditor - Abstract
Bank loans are divided into performing and non-performing loans (NPLs). NPLs are in turn divided into categories characterized by different degrees of difficulty of the debtor and level of risk for the creditor bank. Unlikely to pay loans (UTPs) are NPLs that have a non-zero probability of returning to the performing status. This paper analyzes at the firm and bank level the entire pool of UTPs vis-à-vis firms (UTP firms) in Italy from 2005 to 2019 to detect the characteristics of UTP firms that are more likely to return to the performing state. So far, the literature focused only on status changes from performing to NPLs. To our knowledge, this is the first paper that reverses the perspective and examines the drivers of return to the performing state. The paper shows that the factors most closely related to the new upgrade are — negatively — firm size and absolute value of debts, and — positively — capital and liquidity endowments. Results show that the soundness of lending banks increases the likelihood that firms return to the performing state. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
30. Bias-voltage photoconductance and photoluminescence for the determination of silicon-dielectric interface properties in SiO2/Al2O3 stacks.
- Author
-
Masuch, Paul, Reichel, Christian, Bonilla, Ruy Sebastian, Richter, Armin, and Benick, Jan
- Subjects
CARRIER density ,SURFACE charges ,PHOTOLUMINESCENCE measurement ,PHOTOLUMINESCENCE ,SILICON wafers ,CHARGE carriers ,ABSOLUTE value - Abstract
This paper presents an advanced measurement method for controlling the surface charge carrier density of passivated silicon wafers during photoconductance and photoluminescence measurements, by employing semitransparent poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) electrodes with an applied bias voltage. This is employed to study and analyze charge carrier dynamics in dielectric layers by measuring their direct influence on effective lifetime. With this method, the carrier population at the surface and the effective carrier lifetimes of n- and p-type samples can be investigated, from which the fixed charge carrier density Q
f of the passivation can be extracted. Additionally, the defect density Dit can also be derived from the minimum lifetime values at flatband voltage. In SiO2 /Al2 O3 stacks with varying SiO2 interlayer thickness, it was shown that by changing the SiO2 thickness, the carrier density Qf can be tuned to a wide range of values, which corresponds to the results obtained in other studies. An increase in interlayer thickness resulted in a decrease in Qf . Varying the SiO2 thickness, the behavior of the respective effective lifetime under bias voltage also changes, exhibiting hysteresis-like effects, which are attributed to additional charges getting trapped at the surface during bias-voltage application. This effect is much more pronounced for samples with a thinner SiO2 layer as well as for the n-type samples. Additionally, the doping type also influences the magnitude of Qf , with p-type samples generally reaching lower absolute values. It was also shown that aging of the samples had a significant effect on the measured Qf , which was increased compared to the initial Qf of the passivation. This effect was more pronounced for the n-type samples. The measurements were realized by a cost-effective and easy-to-use microcontroller-based potentiostat, which can be used as a simple add-on to existing photoconductance or photoluminescence measurement setups. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
31. Corrigendum to Power Approximations for Overall Average Effects in Meta-Analysis With Dependent Effect Sizes.
- Subjects
ABSOLUTE value - Abstract
The document is a correction notice for an article titled "Power Approximations for Overall Average Effects in Meta-Analysis With Dependent Effect Sizes" published in the Journal of Educational and Behavioral Statistics. The correction addresses an error in Equation 17 of the article, providing the correct formula. The correction also includes revised values for weights used in the CE working model and corrects the weights reported in an example. The correction has a negligible effect on the power estimates for the CE working model and does not affect the substantive findings of the study. The correction notice also mentions revised versions of Figure 1 and Figure 2A in the original paper, which depict the approximate power of different tests and the difference between approximate power and true power, respectively. The correction does not significantly impact the results presented in these figures. [Extracted from the article]
- Published
- 2024
- Full Text
- View/download PDF
32. Biomass‐based lateral root morphological parameter models for rapeseed (Brassica napus L.).
- Author
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Zhang, Wei‐xin, Wu, Qian, Sun, Chuan‐liang, Ge, Dao‐kuo, Cao, Jing, Liang, Wan‐jie, Yin, Ying‐jun, Li, Hong, Cao, Hong‐xin, Zhang, Wen‐yu, Li, Bai‐ming, and Xin, Yu‐kai
- Subjects
RAPESEED ,ROOT growth ,ABSOLUTE value ,BIOMASS ,CULTIVARS ,SURFACE area - Abstract
Lateral roots, including adventitious roots, are the main component of rapeseed roots with support, absorb, and synthesis functions and their morphological parameters directly affecting the plant's aboveground growth and yield. Root biomass, as a material base for lateral root growth, can be used as a link between plant phenotypes and their physiological processes, as well as to enhance root 3D growth model mechanisms and accuracy. To quantify the relationships between lateral root morphological indices and the corresponding organ biomass for rapeseed, we used two cultivars, NY 22 (conventional) and NZ 1818 (hybrid), and conducted cultivar and fertilizing cylindrical tube experiments during the 2016–2019, with two fertilizer levels, no fertilizer, and 180 kg N ha−1 fertilizer. The lateral root biomass and morphological parameters were determined during the whole growth period. The biomass‐based lateral root morphological parameter models were developed by analyzing the quantitative relationship between the lateral root morphological indices and their corresponding biomass, and the descriptive models were verified with independent experimental data. The results showed that the correlation (r) of simulated and observed values for the lateral root morphological parameters are all greater than 0.9 with significant levels at p < 0.001. The absolute values of the average absolute difference (da) of simulated and observed values for the lateral root length (LLR), lateral root average diameter (ADLR), lateral root surface area (SALR), and lateral root volume (VLR) are −30.408 cm, −0.003 mm, 12.902 cm2, and 0.039 cm3, respectively. The RMSE values are 175.183 cm, 0.010 mm, 59.710 cm2, and 1.513 cm3, respectively. The ratio of da to the average observed values (dap) for the LLR and VLR are all less than 5%, and the ADLR and SALR are all <6%. The models developed in this paper have good performance and reliability for predicting lateral root morphological parameters of rapeseed. The study provides a mechanistic method for linking the rapeseed growth model with the morphological model using corresponding organic biomass and laying a good foundation for establishing a 3D morphological model for rapeseed root system based on biomass. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
33. Economical Design of Drip Irrigation Control System Management Based on the Chaos Beetle Search Algorithm.
- Author
-
Zhang, Yue and Song, Chenchen
- Subjects
MICROIRRIGATION ,SEARCH algorithms ,ABSOLUTE value ,IMAGE encryption ,PROBLEM solving - Abstract
In the realm of existing intelligent drip irrigation control systems, traditional PID control encounters challenges in delivering satisfactory control outcomes, primarily owing to issues related to non-linearity, time-varying behavior, and hysteresis. In order to solve the problem of the unstable operation of the drip irrigation system in an intelligent irrigation system, this paper proposes chaotic beetle swarm optimization (CBSO) based on the BAS (beetle antennae search) longicorn search algorithm, with inertial weights, variable learning factors, and logistic chaos initialization improving global search capabilities. This was accomplished by formulating the optimization objective, which involved integrating the control input's time integral term, the square term, and the absolute value of the error. Subsequently, PID parameter tuning was performed. In order to verify the actual effect of the CBSO algorithm on the PID drip irrigation control system, MATLAB was used to simulate and compare PID control optimized by the GA algorithm, PSO algorithm, and BSO (beetle search optimization) algorithm. The results show that PID control based on CBSO optimization has a short response time, small overshoot, and no oscillation in the steady state process. The performance of the controller is improved, which provides a basis for PID parameter setting for a drip irrigation control system. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
34. International Evidence on the Demand for Money
- Author
-
Fair, Ray C.
- Published
- 1987
- Full Text
- View/download PDF
35. WHICH CHARACTERISTICS OF PRICE-FIXING AGREEMENTS ARE RELATED TO A GREATER DAMAGE TO CONSUMERS?
- Author
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Campio Pinha, Lucas
- Subjects
DAMAGES (Law) ,PRICE fixing ,ANTITRUST law ,ELASTICITY (Economics) ,ABSOLUTE value ,CONSUMERS ,PROSECUTION ,SUPPLY & demand ,PUNISHMENT ,CARTELS - Abstract
Copyright of Revista de Economia Contemporânea is the property of Revista de Economia Contemporanea and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2022
- Full Text
- View/download PDF
36. A BP Neural Network-Based Early Warning Model for Student Performance in the Context of Big Data.
- Author
-
Shi, Chengxiang and Tan, Yun
- Subjects
DATA mining ,APRIORI algorithm ,BIG data ,PSYCHOLOGY of students ,ACADEMIC achievement ,ABSOLUTE value - Abstract
Nowadays, educational data mining technology has received more and more attention from scholars in China, and the application of correlation between student behavior data and student achievement to teaching management has become a hot research topic. Starting from the study of the potential association between book borrowing and student achievement in the big data environment, the paper analyzes the correlation between book borrowing and student achievement based on the Apriori algorithm and concludes that there is a strong correlation rule between book borrowing and student achievement. Based on BP neural network prediction algorithm, the paper constructs an early warning model for student performance by predicting book borrowing through course performance. The absolute value of the error between the predicted value of book borrowing and the real value of borrowing is used as a basis to make early warning for students' performance, so as to realize the monitoring of students' learning situation, thereby providing theoretical suggestions for teachers' teaching and promoting the school's management of students. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
37. A Quantitative Seismic Topographic Effect Prediction Method Based upon BP Neural Network Algorithm and FEM Simulation.
- Author
-
Jiang, Qifeng, Rong, Mianshui, Wei, Wei, and Chen, Tingting
- Subjects
- *
ARTIFICIAL neural networks , *GROUND motion , *FINITE element method , *ALGORITHMS , *ABSOLUTE value - Abstract
Topography can strongly affect ground motion, and studies of the quantification of hill surfaces' topographic effect are relatively rare. In this paper, a new quantitative seismic topographic effect prediction method based upon the BP neural network algorithm and three-dimensional finite element method (FEM) was developed. The FEM simulation results were compared with seismic records and the results show that the PGA and response spectra have a tendency to increase with increasing elevation, but the correlation between PGA amplification factors and slope is not obvious for low hills. New BP neural network models were established for the prediction of amplification factors of PGA and response spectra. Two kinds of input variables' combinations which are convenient to achieve are proposed in this paper for the prediction of amplification factors of PGA and response spectra, respectively. The absolute values of prediction errors can be mostly within 0.1 for PGA amplification factors, and they can be mostly within 0.2 for response spectra's amplification factors. One input variables' combination can achieve better prediction performance while the other one has better expandability of the predictive region. Particularly, the BP models only employ one hidden layer with about a hundred nodes, which makes it efficient for training. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
38. Tropical extensions and Baker-Lorscheid multiplicities for idylls.
- Author
-
Gunn, Sera
- Subjects
- *
NEWTON diagrams , *MULTIPLICITY (Mathematics) , *ABSOLUTE value , *HYPERGROUPS , *ARITHMETIC - Abstract
AbstractIn a recent paper, Baker and Oliver Lorscheid showed that Descartes’s Rule of Signs and Newton’s Polygon Rule can both be interpreted as multiplicities of polynomials over hyperfields. Hyperfields are a generalization of fields which encode things like the arithmetic of signs or of absolute values. By looking at multiplicities of polynomials over such algebraic structures, Baker and Lorscheid showed that you can recover the rules of Descartes and Newton. In this paper, we define tropical extensions for idylls. Such extensions have appeared for semirings with negation symmetries in the work of Akian-Gaubert-Guterman and for hypergroups and hyperfields in the work of Bowler-Su. Examples of tropical extensions are extending the tropical hyperfield to higher ranks, or extending the hyperfield of signs to the tropical real hyperfield by including a valuation. The results of this paper concern the interaction of multiplicities and tropical extensions. First, there is a lifting theorem from initial forms to the entire polynomial from which we will show that multiplicities for a polynomial are equal to the corresponding multiplicity for some initial form. Second, we show that tropical extensions preserve the property that the sum of all multiplicities is bounded by the degree. Consequentially, we have this degree bound for every stringent hyperfield. This gives a partial answer to a question posed by Baker and Lorscheid about which hyperfields have this property. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
39. Monocular Absolute Depth Estimation from Motion for Small Unmanned Aerial Vehicles by Geometry-Based Scale Recovery.
- Author
-
Zhang, Chuanqi, Weng, Xiangrui, Cao, Yunfeng, and Ding, Meng
- Subjects
DRONE aircraft ,MONOCULARS ,REMOTELY piloted vehicles ,ORTHOGONAL matching pursuit ,IMAGE sensors ,GEOMETRIC modeling ,ABSOLUTE value - Abstract
In recent years, there has been extensive research and application of unsupervised monocular depth estimation methods for intelligent vehicles. However, a major limitation of most existing approaches is their inability to predict absolute depth values in physical units, as they generally suffer from the scale problem. Furthermore, most research efforts have focused on ground vehicles, neglecting the potential application of these methods to unmanned aerial vehicles (UAVs). To address these gaps, this paper proposes a novel absolute depth estimation method specifically designed for flight scenes using a monocular vision sensor, in which a geometry-based scale recovery algorithm serves as a post-processing stage of relative depth estimation results with scale consistency. By exploiting the feature correspondence between successive images and using the pose data provided by equipped navigation sensors, the scale factor between relative and absolute scales is calculated according to a multi-view geometry model, and then absolute depth maps are generated by pixel-wise multiplication of relative depth maps with the scale factor. As a result, the unsupervised monocular depth estimation technology is extended from relative depth estimation in semi-structured scenes to absolute depth estimation in unstructured scenes. Experiments on the publicly available Mid-Air dataset and customized data demonstrate the effectiveness of our method in different cases and settings, as well as its robustness to navigation sensor noise. The proposed method only requires UAVs to be equipped with monocular camera and common navigation sensors, and the obtained absolute depth information can be directly used for downstream tasks, which is significant for this kind of vehicle that has rarely been explored in previous depth estimation studies. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
40. Investigation into the Characteristics of Expansion and Compression Deformation of Interbedded Weak Expansive Rocks in Water Immersion.
- Author
-
Wang, Yaning, Li, Yuchen, Qin, Haoyu, Zhu, Yangui, Yao, Yibo, Jin, Jin, Zheng, Tao, Qian, Qingting, and Chen, De
- Subjects
WATER immersion ,HIGH speed trains ,ABSOLUTE value ,STRUCTURAL engineering ,TIME series analysis ,ROCK deformation - Abstract
In order to investigate the deformation characteristics of interbedded weak expansive rocks in water immersion, the sandstone–mudstone interbedded structures were taken as the object of this study. A total of 27 sets of indoor immersion tests were designed with three influencing factors, namely, the layer thickness ratios of sandstone and mudstone (1:1, 2:1, 3:1), the occurrence of the rock layers (flat, oblique, and vertical), and the overburden loadings (0 kPa, 12.5 kPa, and 25 kPa). Tests were conducted to obtain the deformation time series data of the samples during the immersion loading process. Based on this, the influence pattern of each influencing factor on the sample deformation was analyzed individually. The results show that with the increase in overburden loading and rock inclination angle, the sample develops from expansion deformation to compression deformation. Changes in the layer thickness ratio will not change the deformation trend of the sample, and the decrease in the relative mudstone content will only reduce the absolute value of the sample's expansion and compression deformation. The deformation stability rate of the sample under load is 5~7 times that under no load. The increase in layer thickness ratio and rock inclination angle will lead to different degrees of attenuation of sample expansion force in the range of 8.91~38.68% and 51.00~58.83%, respectively. The research results of this paper can provide a meaningful reference for the design and maintenance of a high-speed railway subgrade in a weak expansive rock area with an interbedded structure. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
41. 영상에서 화소 분포 및 공간 가중치 기반의 AWGN 제거 알고리즘.
- Author
-
정경석 and 김남호
- Subjects
ADDITIVE white Gaussian noise ,DIGITAL cameras ,DIGITAL technology ,DIGITAL images ,ABSOLUTE value - Abstract
Due to the widespread use of mobile devices and digital cameras, the usage of image data on various online platforms and social media has been rapidly increasing. However, during the data processing, digital images can exhibit various types of noise, with Additive White Gaussian Noise being one of the most common types. Various types of filters have been studied to remove such noise, but traditional methods have shown inadequate performance in either low-frequency or high-frequency regions. Therefore, this paper proposes an AWGN removal algorithm based on pixel distribution and spatial weighting. The algorithm utilizes absolute deviation values to analyze pixel data distribution, and based on this analysis, it separates each local mask into low-frequency and high-frequency regions. Additionally, it adaptively applies the algorithm by considering the pixel distribution in each region to effectively remove noise. Simulation results demonstrated that the proposed algorithm effectively preserved detailed information in high-frequency regions while also exhibiting excellent noise removal performance in low-frequency regions. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
42. Cost-Efficient Approximation for Magnitude of a Complex Signal.
- Author
-
Wu, Chih-Feng and Shiue, Muh-Tian
- Subjects
SIGNALS & signaling ,AUTOMATIC gain control ,MATHEMATICAL models ,MATHEMATICAL analysis ,DESIGN templates - Abstract
In this paper, a signal model and a mathematical analysis of an efficient approach are derived to acquire the approximate magnitude of a complex signal by inducing a pre-biased or a pre-scaled factor in the design criteria. According to the deductive results, the pre-biased or pre-scaled factor can be 2∼3 dB, which is determined through its application. The numerical evaluations show that the mean square error (MSE) of the proposed efficient approach for the random signal is around −33 dB. Based on the design templates for the considered approaches, the occupied areas of the proposed type-1 and -2 approaches are merely 0.13 and 0.09 times the area of the direct-method, respectively. As a result, the proposed efficient approach is certainly a cost-efficient method for obtaining the approximate magnitude of a complex signal. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
43. A Study on the Transient Characteristics of the Power-Off Transition Process of a Double-Volute Centrifugal Pump.
- Author
-
Lu, Lifeng, Ren, Ziwei, Wang, Zhongzan, Zhou, Wenjie, Li, Siwei, Dai, Jin, Yang, Chunxia, and Dang, Mengfan
- Subjects
CENTRIFUGAL pumps ,ELECTRIC power failures ,ABSOLUTE value ,COMPUTER performance ,INTERNAL friction - Abstract
A double-volute centrifugal pump is a very important pump type; the internal flow field of a centrifugal pump will change drastically during the transition process of power failure, which will affect the safety and stability of the pump's operation. In this paper, the CFD numerical simulation method is used, and the UDF procedure is developed to realize the continuous update of the impeller speed at each time step. The working parameters, such as the torque and flow rate at the instantaneous moment, are obtained through the sequential iteration of each small step, and a numerical simulation of the power-off transient is carried out on a double-volute centrifugal pump; additionally, the changes in the external characteristic parameters and the internal flow field of the centrifugal pump are analyzed in detail. The results show that the double-volute centrifugal pump experienced four different modes after power failure, namely pump mode, braking mode, turbine mode, and runaway mode, and the absolute values of the runaway speed and runaway flow rate are 1.465 times and 1.21 times the initial values, respectively. Through the analysis of the flow field in different regions, the change processes of the generation, development, and disappearance of the vortex at each position of the centrifugal pump are obtained, and the change and development processes of the internal velocity gradient of the centrifugal pump are obtained. In addition, it is found that the high-speed area located in the second volute runner is larger than that of the first volute runner because the second volute runner is shorter and narrower than the first volute runner. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
44. Intumescent coatings based on polyfurfuryl alcohol: a design-of-experiments approach.
- Author
-
Marefat Seyedlar, Roghayyeh, Imani, Mohammad, and Mirabedini, Seyed Mojtaba
- Subjects
PROTECTIVE coatings ,SURFACE coatings ,ALKYD resins ,MILD steel ,ABSOLUTE value ,MICROSCOPY - Abstract
The aim of this paper was to investigate intumescent coatings based on polyfurfuryl alcohol (PFA) resin as a binder benefiting from high char yield and low smoke emission. To this end, the coatings composition in terms of PFA binder resin, long oil alkyd plasticizing resin, TiO
2 pigment, and flame-retardant additives (FR) was changed as input parameters according to a mixture design-of-experiments. The corresponding changes in the backside temperature of mild steel substrate (Tb ), residual char expansion ratio, limiting oxygen index, and char residue (wt% @1000 °C) were studied as the response variables describing fire performance characteristics of the coatings. The results showed that the backside temperature of the plate increased and the expansion ratio decreased with increasing in the alkyd resin concentration. Also, the flame-retardant efficiency of coatings strongly depends on the content of FR additives. When the content of PFA and alkyd resin was increased at a high level (35 and 4 wt%, respectively), the Tb of the coated plates reached 415 °C rapidly, due to the cracking of the coating and the lower concentration of FR additives. However, the formula with higher FR content, i.e., 68 wt%, showed the lowest Tb value ca. 128 °C. Flame-retardant characteristics directly depended on the expansion ratio of the coatings and the morphology of the char layer remaining on the substrate after the flame test; therefore, coatings with a higher expansion ratio showed lower backside temperature. The findings were supported by examining of the remaining char morphology after a flame test by optical microscopy and validated by comparing the predicted and actual responses for optimization. The value of absolute relative deviation was obtained in the range of 1.6–7.9, which indicates a good agreement between the proposed and experimental results. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
45. Better approximations for quasi-convex functions.
- Author
-
Kadakal, Huriye
- Subjects
INTEGRAL inequalities ,DIFFERENTIABLE functions ,ABSOLUTE value ,INTEGRAL functions - Abstract
In this paper, by using Hölder-İşcan, Hölder integral inequality and an general identity for differentiable functions we can get new estimates on generalization of Hadamard, Ostrowski and Simpson type integral inequalities for functions whose derivatives in absolute value at certain power are quasi-convex functions. It is proved that the result obtained Hölder-İşcan integral inequality is better than the result obtained Hölder inequality. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
46. Ostrowski type inequalities via ψ−(α,β,γ,δ)− convex function.
- Author
-
Hassan, Ali and Khan, Asif R.
- Subjects
INTEGRAL inequalities ,ABSOLUTE value - Abstract
In this paper, we are introducing very first time the class of (α, β, γ, δ)-convex function in mixed kind, which is the generalization of many classes of convex functions. We would like to state well-known Ostrowski inequal- ity via Montgomery identity for ψ - (α, β, γ, δ)-convex function in mixed kind. In addition, we establish some Ostrowski type inequalities for the class of functions whose derivatives in absolute values at certain powers are ψ – (α, β, γ, δ)-convex functions in mixed kind by using different techniques including Hölder's inequality and power mean inequality. Also, various established results would be captured as special cases. Moreover, some applications in terms of special means would also be given. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
47. Modulus-based block triangular splitting iteration method for solving the generalized absolute value equations.
- Author
-
Dai, Pingfei and Wu, Qingbiao
- Subjects
ABSOLUTE value ,MATRIX inversion ,EQUATIONS ,ESTIMATION theory ,LINEAR equations ,LINEAR systems - Abstract
In this paper, we focus on solving the generalized absolute value equations (GAVE). We present a new method named as modulus-based block triangular splitting iteration (MBTS) method based on the block matrix structure resulting from the transformation of the GAVE into two equations. This method is developed by decomposing the matrix into diagonal and triangular matrices, as well as applying a series of suitable combination and modification techniques. The advantage of the MBTS method is that it is not necessary to solve the inverse of the coefficient matrix of the linear equation system during each iteration, which greatly improves the computational speed and reduces its storage requirements. In addition, we present some convergent theorems proving by different techniques and the estimate of the required number of iteration steps. Furthermore, in the accompanying corollaries, we provide some estimations for choosing appropriate parameter values. Finally, we validated the effectiveness and efficiency of our newly developed method through two numerical examples of the GAVE. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
48. An Explicit Form of Ramp Function.
- Author
-
Venetis, John Constantine
- Subjects
DIGITAL signal processing ,ORTHOGONAL polynomials ,APPLIED sciences ,CONTINUOUS functions ,ABSOLUTE value - Abstract
In this paper, an analytical exact form of the ramp function is presented. This seminal function constitutes a fundamental concept of the digital signal processing theory and is also involved in many other areas of applied sciences and engineering. In particular, the ramp function is performed in a simple manner as the pointwise limit of a sequence of real and continuous functions with pointwise convergence. This limit is zero for strictly negative values of the real variable x , whereas it coincides with the independent variable x for strictly positive values of the variable x . Here, one may elucidate beforehand that the pointwise limit of a sequence of continuous functions can constitute a discontinuous function, on the condition that the convergence is not uniform. The novelty of this work, when compared to other research studies concerning analytical expressions of the ramp function, is that the proposed formula is not exhibited in terms of miscellaneous special functions, e.g., gamma function, biexponential function, or any other special functions, such as error function, hyperbolic function, orthogonal polynomials, etc. Hence, this formula may be much more practical, flexible, and useful in the computational procedures, which are inserted into digital signal processing techniques and other engineering practices. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
49. Study of 10 kW Vanadium Flow Battery Discharge Characteristics at Different Load Powers.
- Author
-
Rashitov, Ilia, Voropay, Aleksandr, Tsepilov, Grigoriy, Kuzmin, Ivan, Loskutov, Alexey, Osetrov, Evgeny, Kurkin, Andrey, and Lipuzhin, Ivan
- Subjects
FLOW batteries ,VANADIUM redox battery ,LEAD-acid batteries ,ELECTRIC batteries ,CURVE fitting ,ABSOLUTE value ,SERVICE life ,ENERGY storage - Abstract
Vanadium redox flow batteries are promising energy storage devices and are already ahead of lead–acid batteries in terms of installed capacity in energy systems due to their long service life and possibility of recycling. One of the crucial tasks today is the development of models for assessing battery performance and its residual resource based on the battery's present state. A promising method for estimating battery capacity is based on analyzing present voltage and current values under various load conditions. This paper analyzes the discharge characteristics of a 10 kW all-vanadium redox flow battery at fixed load powers from 6 to 12 kW. A linear dependence of operating voltage and initial discharge voltage on load power is established. It is also determined that the slope of the discharge curve linear section does not increase linearly in absolute value, and the Box–Lucas model can be used to describe it. Models for predicting current VRFB capacity based on different curve fitting functions are proposed. These models can be used to roughly estimate battery capacity at different load powers. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
50. A Modified Spectral Conjugate Gradient Method for Absolute Value Equations Associated with Second-Order Cones.
- Author
-
Gao, Leifu, Liu, Zheng, Zou, Jingfei, and Wang, Zengwei
- Subjects
ABSOLUTE value ,EQUATIONS ,CONJUGATE gradient methods - Abstract
In this paper, we propose a modified spectral conjugate gradient (MSCG) method for solving absolute value equations associated with second-order cones (SOCAVEs). Some properties of the SOCAVEs are analyzed, and the global convergence of the MSCG method is discussed in depth. Numerical experiments are given to illustrate the effectiveness and competitiveness of our algorithm. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
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