ADVANCES IN ASTRONOMY 在天文学、天体物理学和宇宙学的所有领域发表文章。该杂志接受对天体和更广阔的宇宙的观测和理论调查，以及关于他们研究的新方法和仪器的报告。

The journal "Advances in Astronomy" covers all areas of astronomy, astrophysics, and cosmology, publishing relevant research articles. It accepts observational and theoretical studies of celestial bodies and the broader universe, as well as reports on new methods and instruments related to their research.

《Advances in Astronomy》期刊涵盖天文学、天体物理学和宇宙学的各个领域，发表相关的研究文章。该杂志接受对天体及更广阔宇宙的观测和理论研究，以及关于新方法和仪器的报告。

Advances in Astronomy

In this work, we construct a new model of compact stars in the presence of anisotropic matter in the Rastall theory of gravity. For this, we considered the anisotropic matter content when formulating the Rastall field equations. Secondly, the Tolman–Oppenheimer–Volkoff (TOV) equation in the context of Rastall theory is formulated. We apply the Finch–Skea ansatz in the static and spherically symmetric geometry to obtain the analytic solution of the derived field equations in the Rastall theory of gravity. We match the internal solution to the corresponding external Schwarzschild space‐time in order to determine the values of the unknown constants involved in the Rastall field equations due to the Finch–Skea ansatz. The resulting model is applied to a few prominent compact stars in order to verify its physical viability. Energy conditions, the TOV equation, stability analysis via sound speeds (radial and transverse in this case), equation of state parameters, mass function, compactness, and surface redshift are some of the analytical expressions that are examined in this inquiry. In order to verify the physical acceptance of the obtained results, we provided a graphical analysis of some necessary analytical expressions. Also, the numerical values of some physical parameters are calculated and are presented in the tabular form to observe the Buchdahl limit and some other important criterion. We note that our model is well consistent with the physical requirements.

M. R. Shahzad

M. Amjad

Y. M. Abo Essa

K. El-Rashidy

Faisal Rasheed

Khalil Hadi Hakami

Homan Emadifar

Study of Anisotropic Compact Star Model in Modified Gravity Using Finch–Skea Geometry

修正引力中使用Finch–Skea几何的各向异性致密星模型研究

The QiTai Radio Telescope (QTT) will be equipped with the active surface adjustment system (ASAS) to correct the main reflector deformation caused by environmental loading. In order to guarantee the stability and performance of the active surface system under fault conditions, it is necessary to adopt the fault-tolerant method when actuator faults have occurred. In this paper, a fault control method based on actuator faults weighting is proposed to solve the active surface fault control problem. According to the coordinates of the adjustable points of the panels corresponding to the faulty actuators, a new paraboloid is fitted by a weighted health matrix, and the fitting surface is taken as the target to adjust the surface shape.

Danqing Zhang

Binbin Xiang

Aili Yusup

Na Wang

Guljaina Kazezkhan

Fault Tolerance for Active Surface System with Actuator Faults

具有执行器故障的主动表面系统的容错性

This study is devoted to explore bouncing cosmology in the context of <math xmlns="http://www.w3.org/1998/Math/MathML" id="M2"> <mi>f</mi> <mfenced open="(" close=")" separators="|"> <mrow> <mi mathvariant="script">G</mi> <mo>,</mo> <mi>T</mi> </mrow> </mfenced> </math> theory of gravity. For this purpose, a Gauss–Bonnet cosmological model with logarithmic trace term is considered. In particular, the possibility of obtaining bouncing solutions by considering two equations of state parameters is investigated. A graphical analysis is provided for analyzing the obtained bouncing solutions. The energy conditions are discussed in detail. It is interesting to notice that null and strong energy conditions are violated near the neighborhood of bouncing points justifying the accelerating universe in the light of the recent observational data. The behavior of the scale factor, red shift function, deceleration parameter, and Hubble parameter is also debated. An important feature of the current study is the discussion of conservation equation in <math xmlns="http://www.w3.org/1998/Math/MathML" id="M3"> <mi>f</mi> <mfenced open="(" close=")" separators="|"> <mrow> <mi mathvariant="script">G</mi> <mo>,</mo> <mi>T</mi> </mrow> </mfenced> </math> gravity. The possibility of some suitable constraint equations which recover the standard conservation equation is discussed, and all the free parameters are assumed accordingly. All the results in this study suggest that the proposed <math xmlns="http://www.w3.org/1998/Math/MathML" id="M4"> <mi>f</mi> <mfenced open="(" close=")" separators="|"> <mrow> <mi mathvariant="script">G</mi> <mo>,</mo> <mi>T</mi> </mrow> </mfenced> </math> gravity model provides good bouncing solutions with the chosen EoS parameters.

M. Farasat Shamir

Bouncing Cosmology in <math xmlns="http://www.w3.org/1998/Math/MathML" id="M1"> <mi>f</mi> <mfenced open="(" close=")" separators="|"> <mrow> <mi>G</mi> <mo>,</mo> <mi>T</mi> </mrow> </mfenced> </math> Gravity with Logarithmic Trace Term

带有对数迹项的<math xmlns="http://www.w3.org/1998/Math/MathML" id="M1"> <mi>f</mi> <mfenced open="(" close=")" separators="|"> <mrow> <mi>G</mi> <mo>,</mo> <mi>T</mi> </mrow> </mfenced> </math>引力中的反弹宇宙学

Extensions of fuzzy sets to broader contexts constitute one of the leading areas of research in the context of problems in artificial intelligence. Their aim is to address decision-making problems in the real world whenever obtaining accurate and sufficient data is not a straightforward task. In this way, spherical fuzzy sets were recently introduced as a step beyond to modelize such problems more precisely on the basis of the human nature, thus expanding the space of membership levels, which are defined under imprecise circumstances. The main goal in this study is to apply the spherical fuzzy set version of Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS), a well-established multicriteria decision-making approach, in the context of planetary defense. As of the extraction of knowledge from a group of experts in the field of near-Earth asteroids, they rated four deflection technologies of asteroids (kinetic impactor, ion beam deflection, enhanced gravity tractor, and laser ablation) that had been previously assessed by means of the classical theory of fuzzy series. This way, a comparative study was carried out whose most significant results are the kinetic impactor being the most suitable alternative and the spherical fuzzy set version of the TOPSIS approach behaves more sensitively than the TOPSIS procedure for triangular fuzzy sets with regard to the information provided by our group of experts.

M. Fernández-Martínez

J. M. Sánchez-Lozano

Assessment of Near-Earth Asteroid Deflection Techniques via Spherical Fuzzy Sets

近地小行星偏转技术评估：基于球形模糊集的方法

The helium burning phase represents the second stage that the star used to consume nuclear fuel in its interior. In this stage, the three elements, carbon, oxygen, and neon, are synthesized. The present paper is twofold: firstly, it develops an analytical solution to the system of the conformable fractional differential equations of the helium burning network, where we used, for this purpose, the series expansion method and obtained recurrence relations for the product abundances, that is, helium, carbon, oxygen, and neon. Using four different initial abundances, we calculated 44 gas models covering the range of the fractional parameter <math xmlns="http://www.w3.org/1998/Math/MathML" id="M1"><mi>α</mi><mo>=</mo><mn>0.5</mn><mo>−</mo><mn>1</mn></math> with step <math xmlns="http://www.w3.org/1998/Math/MathML" id="M2"><mi mathvariant="normal">Δ</mi><mi>α</mi><mo>=</mo><mn>0.05</mn></math> . We found that the effects of the fractional parameter on the product abundances are small which coincides with the results obtained by a previous study. Secondly, we introduced the mathematical model of the neural network (NN) and developed a neural network algorithm to simulate the helium burning network using a feed-forward process. A comparison between the NN and the analytical models revealed very good agreement for all gas models. We found that NN could be considered as a powerful tool to solve and model nuclear burning networks and could be applied to the other nuclear stellar burning networks.

Emad A.-B. Abdel-Salam

Mohamed I. Nouh

Yosry A. Azzam

M. S. Jazmati

Conformable Fractional Models of the Stellar Helium Burning via Artificial Neural Networks

柔性分数模型通过人工神经网络模拟恒星氦燃烧

In this work, we study the cosmological dynamics of the early universe by employing a small field potential in the context of multifield inflation. By investigating analytically the cosmological observables, such as the number of e-folds <math xmlns="http://www.w3.org/1998/Math/MathML" id="M1"><mi>N</mi></math> , potential slow-roll parameters <math xmlns="http://www.w3.org/1998/Math/MathML" id="M2"><msub><mrow><mi>ϵ</mi></mrow><mrow><mi>V</mi></mrow></msub></math> , <math xmlns="http://www.w3.org/1998/Math/MathML" id="M3"><msub><mrow><mi>η</mi></mrow><mrow><mi>V</mi></mrow></msub></math> , and spectral index <math xmlns="http://www.w3.org/1998/Math/MathML" id="M4"><msub><mrow><mi>n</mi></mrow><mrow><mi>s</mi></mrow></msub></math> which carry significant information, we show that they impact the inflationary universe considerably. The tensor-to-scalar ratio concerning the curvature perturbation is worked out for the potential under consideration which is another significant observable and comes out to be nonnegative. In multifield models of inflation, both types of curvature and isocurvature perturbations exist, while, in the present work, during the slow-roll, isocurvature perturbations are suppressed and therefore can be neglected. The surviving perturbations which are due to the curvature only can be tackled suitably by a mechanism developed by Sasaki and Stewart known as Sasaki–Stewart formalism. The effect of augmenting the number of e-folds on the power spectrum through the spectral index and its impact on the observable parameters of the slow-roll inflationary phase is observed by carrying out the analysis. It is observed analytically that the spectrum of multifield inflation is effectively different than its corresponding single-field inflation. The field values and their masses affect the results profoundly at the time of horizon-crossing.

Muhammad Zahid Mughal

Feroz Khan

Fuad A. Awwad

Emad A. A. Ismail

A Study of the Early Cosmic Dynamics in a Multifield Model of Inflation and Curvature Perturbations

多场模型中早期宇宙动力学及曲率扰动的研究

This paper presents forecast and investigation of the variation in ionospheric Total Electron Content (TEC) during the solar eclipses (SEs) of December 2019 and June 2020 using three different methods: Deep Autoregressive model (DeepAR), Feed-Forward Neural Network (FFNN), and Ordinary Kriging-based Surrogate Model (OKSM), and the TEC data predicted by DeepAR, FFNN, and OKSM were compared with the actual TEC during the observation days. The study was conducted based on GPS data taken from the IISC receiver located in Bangalore, India, during the SEs which happened on 26.12.2019 and 21.06.2020. The TEC data were examined to assess the effect of solar eclipses on TEC values. Eighty-day prior TEC data for the IISC station are gathered from IONOLAB servers along with the other parameter data like Dst, Ap, F10.7, and Kp taken from OMNIWEB servers which were used to predict TEC. The reliability of the forecasted results is evaluated using numerical factors like Normalized Root Mean Square Error (NRMSE), Correlation Coefficient (CC), Root Mean Square Error (RMSE), Mean Absolute Error (MAE), and R-squared. The study demonstrates the usefulness of combining multiple methods for analyzing TEC variations during SEs and highlights the potential of OKSM, FFNN, and DeepAR models for studying TEC variation in the same context. The findings may be useful for satellite broadcasting and navigational services and for further research into the influence of solar eclipses on the TEC changes.

R. Mukesh

Sarat C. Dass

Negash Lemma Gurmu

M. Vijay

S. Kiruthiga

S. Mythili

D. Venkata Ratnam

V. B. S. Srilatha Indira Dutt

Forecasting Ionospheric TEC Changes Associated with the December 2019 and June 2020 Solar Eclipses: A Comparative Analysis of OKSM, FFNN, and DeepAR Models

预测2019年12月和2020年6月日食相关的电离层TEC变化：OKSM、FFNN和DeepAR模型的比较分析

The need for precise radio telescope pointing has driven great attention to investigating the effect of antenna local deformation or irregularity, such as unevenness in the azimuth track. Although the track-alidade interaction model is commonly used to investigate the pointing effect of track unevenness (such as the works on DSN 34 m antennas and the Green Bank Telescope), few experiments have been done to test the effectiveness of this model independently from the overall pointing model. To address this issue, a method utilizing an optical pointing telescope (OPT) for determining the impact of track unevenness on pointing is proposed. This method uses a group of reference pointing data collected by an OPT mounted at the bottom of the antenna alidade to extract the twist effect of the alidade from the radio telescope pointing data, thus compared with the predicted twist by the track-alidade model. This method was applied to the 26 meter Nanshan Radio Telescope (NSRT 26 m), achieving good agreement with the model-predicted values.

Ye Yuan

Zhi-Yong Liu

Measuring Track-Related Pointing Errors on the Nanshan Radio Telescope with an Optical Pointing Telescope

使用光学指向望远镜测量南山射电望远镜的轨道相关指向误差

This paper presents a composite control algorithm for the radio telescope servo control system to address the target tracking and matched/mismatched disturbance suppression problems. The algorithm consists of the equivalent-input-disturbance (EID) approach and the optimal control method. An EID estimator is developed using the difference between the estimated output of the state observer and the measurement output and then the estimate of the EID is fed forward into the control input to reject the disturbance. A cost function with clear physical meaning is selected and the weighting parameters are adjusted for the optimal controller to improve tracking performance. Considering the nonminimum phase characteristics of the radio telescope system, the state observer gain is computed using the linear matrix inequality (LMI) method. The system stability is analyzed using the small gain theorem, and the linear quadratic regulator (LQR) control method is utilized to determine the state feedback gain. Finally, the composite controller is designed for an identified telescope model. Simulation results show that for the tracking performance, the settling time of proposed method is 1.13 s and reduces by about 0.32 s and 0.87 s than that of the ADRC controller and PI controller, respectively. For the antidisturbance performance, the RMS value and the maximum error of the proposed method are 0.0039 and 0.0128, which are 42.86% and 40.38% of the ADRC controller and 30.71% and 27.77% of the PI controller, respectively, which indicates that the proposed method has better control performance. In addition, the proposed controller has certain robustness to systematic parameter perturbations.

Lei Yang

Zhiyong Liu

Ning Li

Tracking and Disturbance Suppression of the Radio Telescope Servo System Based on the Equivalent-Input-Disturbance Approach

基于等效输入干扰方法的射电望远镜伺服系统跟踪与扰动抑制

Abbreviation	Adv. Astron.
Journal Impact	1.61
Quartiles(Global)	ASTRONOMY & ASTROPHYSICS(Q3)

ISSN	1687-7969, 1687-7977
h-index	34

Publication Information	Publisher: Hindawi Publishing Corporation，Publishing cycle: ，Journal Type: journal，Open Access Journals: Yes
Basic data	Year of publication: 2010，Proportion of original research papers: 100.00%，Self Citation Rate:6.20%， Gold OA Rate: 100.00%
Journal Fees	$1080Details
Average review cycle	网友分享经验：22 Weeks

Advances in Astronomy

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Study of Anisotropic Compact Star Model in Modified Gravity Using Finch–Skea Geometry

Fault Tolerance for Active Surface System with Actuator Faults

Bouncing Cosmology in $f (G, T)$ Gravity with Logarithmic Trace Term

Assessment of Near-Earth Asteroid Deflection Techniques via Spherical Fuzzy Sets

Conformable Fractional Models of the Stellar Helium Burning via Artificial Neural Networks

A Study of the Early Cosmic Dynamics in a Multifield Model of Inflation and Curvature Perturbations

Forecasting Ionospheric TEC Changes Associated with the December 2019 and June 2020 Solar Eclipses: A Comparative Analysis of OKSM, FFNN, and DeepAR Models

Measuring Track-Related Pointing Errors on the Nanshan Radio Telescope with an Optical Pointing Telescope

Tracking and Disturbance Suppression of the Radio Telescope Servo System Based on the Equivalent-Input-Disturbance Approach

Study of Anisotropic Compact Star Model in Modified Gravity Using Finch–Skea Geometry

Advances in Astronomy

Journal Citation Format

A journal article with 1 author

A journal article with 2 authors

A journal article with 3 authors

A journal article with 5 or more authors

Books Citation Format

Thesis Citation Format

Web sites Citation Format

Patent Citation Format

Staying up late manually editing references? ivySCI automatically matches journals and helps you generate references with a single click.

Share Submission Experience

Study of Anisotropic Compact Star Model in Modified Gravity Using Finch–Skea Geometry

Fault Tolerance for Active Surface System with Actuator Faults

Bouncing Cosmology in f G , T Gravity with Logarithmic Trace Term

Assessment of Near-Earth Asteroid Deflection Techniques via Spherical Fuzzy Sets

Conformable Fractional Models of the Stellar Helium Burning via Artificial Neural Networks

A Study of the Early Cosmic Dynamics in a Multifield Model of Inflation and Curvature Perturbations

Forecasting Ionospheric TEC Changes Associated with the December 2019 and June 2020 Solar Eclipses: A Comparative Analysis of OKSM, FFNN, and DeepAR Models

Measuring Track-Related Pointing Errors on the Nanshan Radio Telescope with an Optical Pointing Telescope

Tracking and Disturbance Suppression of the Radio Telescope Servo System Based on the Equivalent-Input-Disturbance Approach

Study of Anisotropic Compact Star Model in Modified Gravity Using Finch–Skea Geometry

Bouncing Cosmology in $f (G, T)$ Gravity with Logarithmic Trace Term