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Implementing and evaluating an automatic centroid moment tensor procedure for the Indonesia region and surrounding areas

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Earth and Planetary Physics 2024年第4期8卷 609-620页

作者： Madlazim Muhammad Nurul Fahmi Dyah Permata Sari Ella Meilianda Sorja Koesuma Physics Department Faculty of Mathematics and Natural SciencesUniversitas Negeri SurabayaSurabaya 60231Indonesia Science Education study program Faculty of Mathematics and Natural SciencesUniversitas Negeri Surabaya 60231SurabayaIndonesia Disaster Science Department Faculty of Mathematics and Natural SciencesUniversitas Syiah KualaAceh 23126Indonesia Physics Department Faculty of Mathematics and Natural SciencesUniversitas Sebelas MaretSolo 57126Indonesia

The purpose of this research was to suggest an applicable procedure for computing the centroid moment tensor(CMT)automatically and in real time from earthquakes that occur in Indonesia and the surrounding *** software was used to estimate the CMT solution by selecting the velocity model that best suited the local and regional geological conditions in Indonesia and the surrounding *** data used in this study were earthquakes with magnitudes of 5.4 to ***-quality,real-time broadband seismographic data were provided by the International Federation of Digital Seismograph Networks Web Services(FDSNWS)and the European Integrated Data Archive(EIDA)Federation in Indonesia and the surrounding ***,the inversion process and filter adjustment were carried out on the seismographic data to obtain good CMT *** CMT solutions from Gisola provided good-quality solutions,in which all earthquake data had A-level quality(high quality,with good variant reduction).The Gisola CMT solution was justified with the Global CMT(GCMT)solution by using the Kagan angle value,with an average of approximately 11.2°.This result suggested that the CMT solution generated from Gisola was trustworthy and *** Gisola CMT solution was typically available within approximately 15 minutes after an earthquake *** it met the quality requirement,it was automatically published on the *** catalog of local and regional earthquake records obtained through this technology holds great promise for improving the current understanding of regional seismic activity and ongoing tectonic *** accurate and real-time CMT solution generated by implementing the Gisola algorithm consisted of moment tensors and moment magnitudes,which provided invaluable insights into earthquakes occurring in Indonesia and the surrounding areas.

关键词： centroid moment tensor Gisola International Federation of Digital Seismograph Networks Web Services(FDSNWS) real time Indonesia

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Spectroscopic Observations of Ten Galactic Wolf–Rayet Stars at Bosscha Observatory:Determination of Stellar Parameters and Mass-loss Rates

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Research in Astronomy and Astrophysics 2024年第9期24卷 9-29页

作者： Hakim Luthfi Malasan Bakuh Danang Setyo Budi Department of Astronomy Faculty of Mathematics and Natural Sciences Institut Teknologi Bandung Bosscha Observatory Institut Teknologi Bandung Master program in Astronomy Faculty of Mathematics and Natural Sciences Institut Teknologi Bandung

We present optical spectra of 10 Galactic Wolf–Rayet（WR） stars that consist of five WN and five WC stars. The optical observation was conducted using a low-resolution spectrograph NEO-R1000（λ/Δλ1000） at GAO-ITB RTS（27.94 cm, F/10.0）, Bosscha Observatory, Lembang. We implemented stellar atmosphere Postdam Wolf–Rayet（PoWR） grid modeling to derive stellar parameters. The normalized optical spectrum can be used to find the best model from the available PoWR grid, then we could derive stellar temperature and transformation radius. To derive luminosity, stellar radius and color excess, we conducted a Spectral Energy Distribution（SED） analysis with additional data on the near-ultraviolet spectrum from the International Ultraviolet Explorer（IUE） database, and UBV and 2MASS JHK broadband filter data. Additional analysis to derive asymptotic terminal wind velocity was conducted from the P-Cygni profile analysis of the high-resolution IUE ultraviolet spectrum. With previously derived parameters, we could determine the mass loss rate of the WR stars. Furthermore, we compared our results with previous work that used PoWR code and the differences are not more than 20%. We conclude that the PoWR spectral grid is sufficient to derive WR stellar parameters quickly and could provide more accurate initial parameter input to the PoWR program code.

关键词： outflows stars: atmospheres stars: mass-loss stars: massive stars: winds stars: Wolf-Rayet

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Mirror symmetry for special nilpotent orbit closures In Memory of Professor Gang Xiao

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Science China mathematics 2024年

作者： Baohua Fu Yongbin Ruan Yaoxiong Wen AMSS HLM and MCM Chinese Academy of Sciences Korea Institute for Advanced study Institute for Advanced study in mathematics Zhejiang University School of Mathematical sciences University of Chinese Academy of Sciences

Motivated by geometric Langlands, we initiate a program to study the mirror symmetry between nilpotent orbit closures of a semisimple Lie algebra and those of its Langlands dual. The most interesting case is Bn via Cn. Classically, there is a famous Springer duality between special orbits. Therefore, it is natural to speculate that the mirror symmetry we seek may coincide with Springer duality in the context of special ***, such a naive statement fails. To remedy the situation, we propose a conjecture which asserts the mirror symmetry for certain parabolic/induced covers of special orbits. Then, we prove the conjecture for Richardson orbits and obtain certain partial results in general. In the process, we reveal some very interesting and yet subtle structures of these finite covers, which are related to Lusztig’s canonical quotients of special nilpotent orbits. For example, there is a mysterious asymmetry in the footprint or range of degrees of these finite covers. Finally, we provide two examples to show that the mirror symmetry fails outside the footprint.

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Density peak clustering using tensor network

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Science China(Information sciences) 2024年第3期67卷 321-322页

作者： Xiao SHI Yun SHANG Institute of mathematics Academy of Mathematics and Systems ScienceChinese Academy of Sciences School of Mathematical sciences University of Chinese Academy of Sciences National Center for mathematics and Interdisciplinary sciences Key Laboratory of ManagementDecision and Information SystemsAcademy of Mathematics and Systems ScienceChinese Academy of Sciences

Tensor networks have been a powerful tool in simulating many-body physics and have recently gained recognition in the machine learning community due to their remarkable representation capabilities. However, using tens... 详细信息

关键词： Tensors

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An eikonal equation-based earthquake location method by inversion of multiple phase arrivals

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Science China Earth sciences 2024年第6期67卷 1802-1817页

作者： Gaoyue LAO Dinghui YANG Shaolin LIU Guiju DONG Wenshuai WANG Kui LIU National Institute of natural Hazards Ministry of Emergency Management of ChinaBeijing 100085China School of Earth sciences Yunnan UniversityKunming 650091China Department of Mathematical sciences Tsinghua UniversityBeijing 100084China School of mathematics and Statistics Ningxia UniversityYinchuan 750021China

The precise determination of earthquake location is the fundamental basis in seismological community,and is crucial for analyzing seismic activity and performing seismic *** arrivals are generally used to practically determine earthquake ***,first-arrival traveltimes are not sensitive to focal ***,they cannot accurately constrain focal *** improve the accuracy,researchers have analyzed the depth phases of earthquake *** traveltimes of depth phases are sensitive to focal depths,and the joint inversion of depth phases and direct phases can be implemented to potentially obtain accurate earthquake ***,researchers can determine earthquake locations in layered *** layered models can only represent the first-order feature of subsurface structures,the advantages of joint inversion are not fully explored if layered models are *** resolve the issue of current joint inversions,we use the traveltimes of three seismic phases to determine earthquake locations in heterogeneous *** three seismic phases used in this study are the first P-,sPg-and *** calculate the traveltimes of the three seismic phases by solving an eikonal equation with an upwind difference scheme and use the traveltimes to determine earthquake *** verify the accuracy of the earthquake location method by the inversion of three seismic phases,we take the 2021 M_(S)6.4 Yangbi,Yunnan earthquake as an example and locate this earthquake using synthetic and real seismic *** tests demonstrate that the eikonal equation-based earthquake location method,which involves the inversion of multiple phase arrivals,can effectively improve earthquake location accuracy.

关键词： Earthquake location Eikonal equation Fast marching method Heterogeneous model

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L vector spaces and L fields

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Science China mathematics 2024年第10期67卷 2195-2216页

作者： Yinhe Peng Liuzhen Wu Academy of mathematics and Systems Science Chinese Academy of Sciences

We construct in ZFC(the Zermelo-Fraenkel system with choice) an L topological vector space—a topological vector space that is an L space—and an L field—a topological field that is an L space. This generalizes earli... 详细信息

关键词： minimal walk topological vector space topological field L space L vector space L field

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Polynomial-Time Key-Recovery Attacks Against NTRURe Encrypt from ASIACCS'15

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Journal of Systems Science & Complexity 2024年第3期37卷 1308-1325页

作者： LIU Zhen PAN Yanbin ZHENG Jinwei School of Cyber Science and Technology Hubei Key Laboratory of Applied MathematicsHubei UniversityWuhan 430062China Key Laboratory of mathematics Mechanization Academy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China School of Mathematical sciences University of Chinese Academy of SciencesBeijing 100190China

In ASIACCS 2015, Nu nez, et al. proposed a proxy re-encryption scheme, named NTRURe Encrypt, based on NTRU, which allows a proxy to translate ciphertext under the delegator’s public key into a re-encrypted ciphertext that can be decrypted correctly by delegatee’s private key. Because of the potential resistance to quantum algorithm, high efficiency and various applications in real life,NTRURe Encrypt has drawn lots of attention and its security has been widely discussed and *** PQCrypto2019, Liu, et al. proposed two key recovery attacks against it. However, their first attack heavily relies on a weaken decryption oracle, and the second attack needs to collect about 260ciphertexts from the same message by theoretical analysis, which makes both of the attacks unrealistic. In this paper, inspired by the broadcast attack against NTRU, the authors find out that for NTRURe Encrypt the delegator and the delegatee can efficiently recover each other’s private key in polynomial time without any unrealistic assumptions. In addition, the authors also show how to fix NTRURe Encrypt to resist the proposed attacks. As a by-product, the authors also show how to commit broadcast attacks against NTRU 2001 with even dg, which was thought infeasible before.

关键词： Broadcast attack key recovery NTRU NTRUReEncrypt

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C^(α)regularity of weak solutions of non-homogeneous ultraparabolic equations with drift terms

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Science China mathematics 2024年第1期67卷 23-44页

作者： Wendong Wang Liqun Zhang School of Mathematical sciences Dalian University of TechnologyDalian 116024China Institute of mathematics Academy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China

We consider a class of non-homogeneous ultraparabolic differential equations with singular drift terms arising from some physical models,and prove that weak solutions are H?lder continuous,which are sharp in some sense and also generalize the well-known De Giorgi-Nash-Moser theory to degenerate parabolic equations satisfying the H?rmander hypoellipticity *** new ingredients are manifested in two aspects:on the one hand,for lower-order terms,we exploit a new Sobolev inequality suitable for the Moser iteration by improving the result of Pascucci and Polidoro(2004);on the other hand,we explore the G-function from an early idea of Kruzhkov(1964)and an approximate weak Poincaréinequality for non-negative weak sub-solutions to prove the H?lder regularity.

关键词： ultraparabolic equations Moser iteration Poincare inequality C^a regularity

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Tracing suspended and bed sediments during high and low water periods using geochemical characteristics-Case study:Vazrood watershed,northern Iran

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Journal of Mountain Science 2024年第2期21卷 470-483页

作者： KARIMI Nabiyeh GHOLAMI Leila KAVIAN Ataollah KHALEDI DARVISHAN Abdulvahed Department of Watershed Management Faculty of Natural ResourcesSari Agricultural Sciences and Natural Resources UniversitySari ***Iran Department of Watershed Management Engineering Faculty of Natural ResourcesTarbiat Modares UniversityNoor ***Iran

Complete and comprehensive information about sediment dynamic and identification of hotspots of sediment production and transport are necessary for understanding the erosion processes and increasing the efficiency of soil and water conservation *** studies used the sediment fingerprint techniques to investigate the contribution of different sources in suspended and bed sediment yield of the ***,the contribution of various land use/land covers in suspended and bed sediment yield for the great Caspian Sea basin is in an aura of ambiguity and the present study was conducted to gather information about an important part of this area in northern Iran,where rangelands are located upstream of Hyrcanian forests and dense agricultural lands are located *** surface soil of different land use/land covers including forest,rangeland,agriculture and streambank lands were sampled in 30 *** and bed sediments were sampled in the watershed outlet in two high and low water *** characteristics of soil and sediment samples containing 59 elements were measured using ICP-OES GBC *** reliable and suitable tracers from 59 elements were then selected using Range test,Kruskal-Wallis and Discriminant Function Analysis,respectively,in FingerPro package of R *** results showed that for suspended sediment,streambank and rangeland had the highest contributions of 86.2%and 47.5%,respectively,in two high and low water *** bed sediment,in two high and low water periods,rangeland and streambank had the highest contributions of 73.8%and 84.4%,*** use change and especially human activities such as agriculture,road construction and development of residential areas along the main river riparian zone has led to a significant increase in suspended and bed sediments.

关键词： Caspian Sea basin FingerPro Geochemistry Sediment transport Tracer combination

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On Minor Left Prime Factorization Problem for Multivariate Polynomial Matrices

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Journal of Systems Science & Complexity 2024年第3期37卷 1295-1307页

作者： LU Dong WANG Dingkang XIAO Fanghui School of mathematics Southwest Jiaotong UniversityChengdu 610031China KLMM Academy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China School of Mathematical sciences University of Chinese Academy of SciencesBeijing 100049China MOE-LCSM School of Mathematics and StatisticsHunan Normal UniversityChangsha 410081China

A new necessary and sufficient condition for the existence of minor left prime factorizations of multivariate polynomial matrices without full row rank is *** key idea is to establish a relationship between a matrix and any of its full row rank *** on the new result,the authors propose an algorithm for factorizing matrices and have implemented it on the computer algebra system *** examples are given to illustrate the effectiveness of the algorithm,and experimental data shows that the algorithm is efficient.

关键词： Free modules Grobner bases minor left prime(MLP) multivariate polynomial matrices polynomial matrix factorizations

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