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Root-Of-Trust for Continuous Integration and Continuous Deployment Pipeline in Cloud Computing
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作者 Abdul Saboor Mohd Fadzil Hassan +4 位作者 Rehan Akbar Erwin Susanto Syed Nasir Mehmood Shah Muhammad Aadil Siddiqui Saeed Ahmed Magsi 《Computers, Materials & Continua》 SCIE EI 2022年第11期2223-2239,共17页
Cloud computing has gained significant use over the last decade due to its several benefits,including cost savings associated with setup,deployments,delivery,physical resource sharing across virtual machines,and avail... Cloud computing has gained significant use over the last decade due to its several benefits,including cost savings associated with setup,deployments,delivery,physical resource sharing across virtual machines,and availability of on-demand cloud services.However,in addition to usual threats in almost every computing environment,cloud computing has also introduced a set of new threats as consumers share physical resources due to the physical co-location paradigm.Furthermore,since there are a growing number of attacks directed at cloud environments(including dictionary attacks,replay code attacks,denial of service attacks,rootkit attacks,code injection attacks,etc.),customers require additional assurances before adopting cloud services.Moreover,the continuous integration and continuous deployment of the code fragments have made cloud services more prone to security breaches.In this study,the model based on the root of trust for continuous integration and continuous deployment is proposed,instead of only relying on a single signon authentication method that typically uses only id and password.The underlying study opted hardware security module by utilizing the Trusted Platform Module(TPM),which is commonly available as a cryptoprocessor on the motherboards of the personal computers and data center servers.The preliminary proof of concept demonstrated that the TPM features can be utilized through RESTful services to establish the root of trust for continuous integration and continuous deployment pipeline and can additionally be integrated as a secure microservice feature in the cloud computing environment. 展开更多
关键词 Root of Trust(RoT) Trusted Platform Module(TPM) cryptoprocessor microservices Hardware Security Modules(HSM) DevOps
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Infrared Spectroscopy-Based Chemometric Analysis for Lard Differentiation in Meat Samples
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作者 Muhammad Aadil Siddiqui M.H.Md Khir +3 位作者 Zaka Ullah Muath Al Hasan Abdul Saboor Saeed Ahmed Magsi 《Computers, Materials & Continua》 SCIE EI 2023年第5期2859-2871,共13页
One of the most pressing concerns for the consumer market is the detection of adulteration in meat products due to their preciousness.The rapid and accurate identification mechanism for lard adulteration in meat produ... One of the most pressing concerns for the consumer market is the detection of adulteration in meat products due to their preciousness.The rapid and accurate identification mechanism for lard adulteration in meat products is highly necessary,for developing a mechanism trusted by consumers and that can be used to make a definitive diagnosis.Fourier Transform Infrared Spectroscopy(FTIR)is used in this work to identify lard adulteration in cow,lamb,and chicken samples.A simplified extraction method was implied to obtain the lipids from pure and adulterated meat.Adulterated samples were obtained by mixing lard with chicken,lamb,and beef with different concentrations(10%–50%v/v).Principal component analysis(PCA)and partial least square(PLS)were used to develop a calibration model at 800–3500 cm^(−1).Three-dimension PCA was successfully used by dividing the spectrum in three regions to classify lard meat adulteration in chicken,lamb,and beef samples.The corresponding FTIR peaks for the lard have been observed at 1159.6,1743.4,2853.1,and 2922.5 cm−1,which differentiate chicken,lamb,and beef samples.The wavenumbers offer the highest determination coefficient R2 value of 0.846 and lowest root mean square error of calibration(RMSEC)and root mean square error prediction(RMSEP)with an accuracy of 84.6%.Even the tiniest fat adulteration up to 10%can be reliably discovered using this methodology. 展开更多
关键词 Fourier transform infrared spectroscopy LARD HALAL PCA PLS RMSEC RMSEP
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Experimental Evaluation of Trilateration-Based Outdoor Localizationwith LoRaWAN
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作者 Saeed Ahmed Magsi Mohd Haris Bin Md Khir +5 位作者 Illani Bt Mohd Nawi Muath Al Hasan Zaka Ullah Fasih Ullah Khan Abdul Saboor Muhammad Aadil Siddiqui 《Computers, Materials & Continua》 SCIE EI 2023年第4期845-862,共18页
Long Range Wide Area Network (LoRaWAN) in the Internet ofThings (IoT) domain has been the subject of interest for researchers. Thereis an increasing demand to localize these IoT devices using LoRaWAN dueto the quickly... Long Range Wide Area Network (LoRaWAN) in the Internet ofThings (IoT) domain has been the subject of interest for researchers. Thereis an increasing demand to localize these IoT devices using LoRaWAN dueto the quickly growing number of IoT devices. LoRaWAN is well suited tosupport localization applications in IoTs due to its low power consumptionand long range. Multiple approaches have been proposed to solve the localizationproblem using LoRaWAN. The Expected Signal Power (ESP) basedtrilateration algorithm has the significant potential for localization becauseESP can identify the signal’s energy below the noise floor with no additionalhardware requirements and ease of implementation. This research articleoffers the technical evaluation of the trilateration technique, its efficiency,and its limitations for the localization using LoRa ESP in a large outdoorpopulated campus environment. Additionally, experimental evaluations areconducted to determine the effects of frequency hopping, outlier removal, andincreasing the number of gateways on localization accuracy. Results obtainedfrom the experiment show the importance of calculating the path loss exponentfor every frequency to circumvent the high localization error because ofthe frequency hopping, thus improving the localization performance withoutthe need of using only a single frequency. 展开更多
关键词 LoRaWAN LOCALIZATION expected signal power(ESP) path loss exponent(PLE) TRILATERATION
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Combined Effect of Concept Drift and Class Imbalance on Model Performance During Stream Classification
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作者 Abdul Sattar Palli Jafreezal Jaafar +3 位作者 Manzoor Ahmed Hashmani Heitor Murilo Gomes Aeshah Alsughayyir Abdul Rehman Gilal 《Computers, Materials & Continua》 SCIE EI 2023年第4期1827-1845,共19页
Every application in a smart city environment like the smart grid,health monitoring, security, and surveillance generates non-stationary datastreams. Due to such nature, the statistical properties of data changes over... Every application in a smart city environment like the smart grid,health monitoring, security, and surveillance generates non-stationary datastreams. Due to such nature, the statistical properties of data changes overtime, leading to class imbalance and concept drift issues. Both these issuescause model performance degradation. Most of the current work has beenfocused on developing an ensemble strategy by training a new classifier on thelatest data to resolve the issue. These techniques suffer while training the newclassifier if the data is imbalanced. Also, the class imbalance ratio may changegreatly from one input stream to another, making the problem more complex.The existing solutions proposed for addressing the combined issue of classimbalance and concept drift are lacking in understating of correlation of oneproblem with the other. This work studies the association between conceptdrift and class imbalance ratio and then demonstrates how changes in classimbalance ratio along with concept drift affect the classifier’s performance.We analyzed the effect of both the issues on minority and majority classesindividually. To do this, we conducted experiments on benchmark datasetsusing state-of-the-art classifiers especially designed for data stream classification.Precision, recall, F1 score, and geometric mean were used to measure theperformance. Our findings show that when both class imbalance and conceptdrift problems occur together the performance can decrease up to 15%. Ourresults also show that the increase in the imbalance ratio can cause a 10% to15% decrease in the precision scores of both minority and majority classes.The study findings may help in designing intelligent and adaptive solutionsthat can cope with the challenges of non-stationary data streams like conceptdrift and class imbalance. 展开更多
关键词 CLASSIFICATION data streams class imbalance concept drift class imbalance ratio
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An RFI Mitigation Pipeline for CRAFTS Multi-beam Data Based on Signal Cross-Correlation Function and SumThreshold Algorithm
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作者 Zong-Hao Chen Shan-Ping You +7 位作者 Xu-Hong Yu Pei Wang Di Li Xiao-Yao Xie Zhi-Jie Liu Chun-Qing Wang Peng Zeng Bin Zhang 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2023年第5期160-171,共12页
The increasing radio frequency interference(RFI)is a well-recognized problem in radio astronomy research.Pulsars and Fast Radio Bursts(FRBs)are high-priority science targets of the ongoing Commercial Radio Astronomy F... The increasing radio frequency interference(RFI)is a well-recognized problem in radio astronomy research.Pulsars and Fast Radio Bursts(FRBs)are high-priority science targets of the ongoing Commercial Radio Astronomy FAST Survey(CRAFTS).To improve the quality of RFI removal in searches of pulsars and FRBs based on CRAFTS multi-beam data,we here propose an intuitive but powerful RFI mitigation pipeline(CCF-ST).The“CCF-ST”is a spatial filter constructed by signal cross-correlation function(CCF)and Sum-Threshold(ST)algorithm.The RFI marking result is saved in a“mask”file,a binary format for RFI masks in PRESTO.Three known pulsars,PSR B0525-21,PSR B0621-04,and PSR J0943+2252 from CRAFTS L-band 19 beams data are used for evaluation of the performance of CCF-ST in comparison with other methods,such as PRESTO’s“rfifind”,ArPLS-ST and ArPLS-SF.The result shows that CCF-ST can reduce effective data loss rate and improves the detected signal-to-noise ratio of the pulsations by~26%and~18%respectively compared with PRESTO’s“rfifind”and ArPLS-ST.The CCF-ST also has the advantage of low computational cost,e.g.,reducing the time consumption by~40%and memory consumption by~90%compared with ArPLS-SF.We expect that the new RFI mitigation and analysis toolkit(CCF-ST)demonstrated in this paper can be applied to CRAFTS and other multi-beam telescope observations to improve the data quality and efficiency of pulsar and FRB searches. 展开更多
关键词 methods data analysis-(stars:)pulsars general-stars neutron
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An Overview of FAST Real-time Fast Radio Burst Searching System
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作者 X.X.Zhang R.Duan +9 位作者 V.Gajjar H.Y.Zhang P.Wang C.H.Niu D.Werthimer J.Cobb S.Y.Li X.Pei Y.Zhu D.Li 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2023年第9期251-263,共13页
In this paper,we report a real-time Fast Radio Burst(FRB)searching system that has been successfully implemented with the 19 beam receiver of the Five-hundred-meter Aperture Spherical radio Telescope(FAST).The relativ... In this paper,we report a real-time Fast Radio Burst(FRB)searching system that has been successfully implemented with the 19 beam receiver of the Five-hundred-meter Aperture Spherical radio Telescope(FAST).The relatively small field of view of FAST makes the search for new FRBs challenging,but its high sensitivity significantly improves the accuracy of FRB localization and enables the detection of high-precision neutral hydrogen absorption lines generated by FRBs.Our goal is to develop an FRB searching system capable of realtime detection of FRBs that allows high-time resolution spectro-temporal studies among the repeated bursts,as well as detailed investigations of these bursts and exploration of FRB progenitor models.The data from each beam of the 19-beam receiver are fed into a high-performance computing node server,which performs real-time searches for pulses with a wide dispersion measure(DM)range of 20–10,000 pc cm^(-3) with step efficiency of 25%in real time.Then,the head node server aggregates all the candidate signals from each beam within a given time,determining their authenticity based on various criteria,including arrival time,pulse width,signal-to-noise ratio and coincidence patterns among the 19 beams.Within the 1.05–1.45 GHz operating bandwidth of the FAST 19beam receiver,the system achieves a frequency resolution of 122.07 kHz and a time resolution of 270.336μs.Subsequently,our team detected a series of bursts with a DM of 566 on 2019 August 30 confirming them as FRB121102.The FRB searching system enables the 19-beam receiver of FAST to detect repeated/one-off pulses/bursts in real time. 展开更多
关键词 Astronomical Instrumentation-Methods and Techniques-instrumentation spectrographs-methods MISCELLANEOUS
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Updated Inventory of Carbon Monoxide in the Taurus Molecular Cloud
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作者 Yan Duan Di Li +4 位作者 Laurent Pagani Paul F.Goldsmith Tao-Chung Ching Chen Wang Jinjin Xie 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2023年第9期56-65,共10页
The most extensive survey of carbon monoxide(CO)gas in the Taurus molecular cloud relied on ^(12)CO and ^(13)CO J=1→0 emission only,distinguishing the region where ^(12)CO is detected without ^(13)CO(named mask 1 reg... The most extensive survey of carbon monoxide(CO)gas in the Taurus molecular cloud relied on ^(12)CO and ^(13)CO J=1→0 emission only,distinguishing the region where ^(12)CO is detected without ^(13)CO(named mask 1 region)from the one where both are detected(mask 2 region)(Goldsmith et al.2008;Pineda et al.2010).We have taken advantage of recent ^(12)CO J=3→2 James Clerk Maxwell Telescope observations,where they include mask 1regions to estimate density,temperature,and N(CO)with a large velocity gradient model.This represents 1395 pixels out of~1.2 million in the mark 1 region.Compared to Pineda et al.(2010)results and assuming a Tkin of 30 K,we find a higher volume density of molecular hydrogen of 3.3×10^(3) cm^(-3),compared to their 250-700 cm^(-3),and a CO column density of 5.7×10^(15)cm^(-2),about a quarter of their value.The differences are important and show the necessity to observe several CO transitions to better describe the intermediate region between the dense cloud and the diffuse atomic medium.Future observations to extend the ^(12)CO J=3→2 mapping further away from the ^(13)COdetected region comprising mask 1 are needed to revisit our understanding of the diffuse portions of dark clouds. 展开更多
关键词 SUBMILLIMETER ISM-ISM clouds-ISM MOLECULES
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Liver Tumor Decision Support System on Human Magnetic Resonance Images:A Comparative Study
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作者 Hiam Alquran Yazan Al-Issa +4 位作者 Mohammed Alslatie Isam Abu-Qasmieh Amin Alqudah Wan Azani Mustafa Yasmin Mohd Yacob 《Computer Systems Science & Engineering》 SCIE EI 2023年第8期1653-1671,共19页
Liver cancer is the second leading cause of cancer death worldwide.Early tumor detection may help identify suitable treatment and increase the survival rate.Medical imaging is a non-invasive tool that can help uncover... Liver cancer is the second leading cause of cancer death worldwide.Early tumor detection may help identify suitable treatment and increase the survival rate.Medical imaging is a non-invasive tool that can help uncover abnormalities in human organs.Magnetic Resonance Imaging(MRI),in particular,uses magnetic fields and radio waves to differentiate internal human organs tissue.However,the interpretation of medical images requires the subjective expertise of a radiologist and oncologist.Thus,building an automated diagnosis computer-based system can help specialists reduce incorrect diagnoses.This paper proposes a hybrid automated system to compare the performance of 3D features and 2D features in classifying magnetic resonance liver tumor images.This paper proposed two models;the first one employed the 3D features while the second exploited the 2D features.The first system uses 3D texture attributes,3D shape features,and 3D graphical deep descriptors beside an ensemble classifier to differentiate between four 3D tumor categories.On top of that,the proposed method is applied to 2D slices for comparison purposes.The proposed approach attained 100%accuracy in discriminating between all types of tumors,100%Area Under the Curve(AUC),100%sensitivity,and 100%specificity and precision as well in 3D liver tumors.On the other hand,the performance is lower in 2D classification.The maximum accuracy reached 96.4%for two classes and 92.1%for four classes.The top-class performance of the proposed system can be attributed to the exploitation of various types of feature selection methods besides utilizing the ReliefF features selection technique to choose the most relevant features associated with different classes.The novelty of this work appeared in building a highly accurate system under specific circumstances without any processing for the images and human input,besides comparing the performance between 2D and 3D classification.In the future,the presented work can be extended to be used in the huge dataset.Then,it can be a reliable,efficient Computer Aided Diagnosis(CAD)system employed in hospitals in rural areas. 展开更多
关键词 Liver tumors ensemble classifier 3D shape features 3D cooccurrence matrix ResNet101
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Cross-correlation Forecast of CSST Spectroscopic Galaxy and MeerKAT Neutral Hydrogen Intensity Mapping Surveys
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作者 Yu-Er Jiang Yan Gong +6 位作者 Meng Zhang Qi Xiong Xingchen Zhou Furen Deng Xuelei Chen Yin-Zhe Ma Bin Yue 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2023年第7期25-36,共12页
Cross-correlating the data on neutral hydrogen(HⅠ)21 cm intensity mapping with galaxy surveys is an effective method to extract astrophysical and cosmological information.In this work,we investigate the cross-correla... Cross-correlating the data on neutral hydrogen(HⅠ)21 cm intensity mapping with galaxy surveys is an effective method to extract astrophysical and cosmological information.In this work,we investigate the cross-correlation of MeerKAT single-dish mode HⅠintensity mapping and China Space Station Telescope(CSST)spectroscopic galaxy surveys.We simulate a survey area of~300 deg~2 of MeerKAT and CSST surveys at z=0.5 using MultiDark N-body simulation.The PC A algorithm is applied to remove the foregrounds of HⅠintensity mapping,and signal compensation is considered to solve the signal loss problem in HⅠ-galaxy cross power spectrum caused by the foreground removal process.We find that from CSST galaxy auto and MeerKAT-CSST cross power spectra,the constraint accuracy of the parameter productΩ_(HⅠ)b_(HⅠ)r_(HⅠ,g)can reach~1%,which is about one order of magnitude higher than the current results.After performing the full MeerKAT HⅠintensity mapping survey with5000 deg~2 survey area,the accuracy can be enhanced to<0.3%.This implies that the MeerKAT-CSST cross-correlation can be a powerful tool to probe the cosmic HⅠproperty and the evolution of galaxies and the Universe. 展开更多
关键词 (cosmology:)large-scale structure of universe (cosmology:)cosmological parameters COSMOLOGY
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青藏高原东缘变形机制的讨论:来自数值模拟结果的限定 被引量:20
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作者 姚琪 徐锡伟 +2 位作者 邢会林 张微 高翔 《地球物理学报》 SCIE EI CAS CSCD 北大核心 2012年第3期863-874,共12页
青藏高原东缘的地壳结构是两种主流青藏高原隆升模式争辩的焦点之一.中下地壳流曾经被认为是高原东缘隆升的主要构造驱动力,但是中上地壳之间低阻低速层的发现及其与2008 MS8.0汶川地震良好的对应关系表明,高原东缘具有向东刚性挤出的... 青藏高原东缘的地壳结构是两种主流青藏高原隆升模式争辩的焦点之一.中下地壳流曾经被认为是高原东缘隆升的主要构造驱动力,但是中上地壳之间低阻低速层的发现及其与2008 MS8.0汶川地震良好的对应关系表明,高原东缘具有向东刚性挤出的可能性.然而大部分关于龙门山断裂的数值模拟仍建立在下地壳流的基础上,仅将低阻低速层作为断裂的延续或是弱化地壳物性参数的软弱层,而非能够控制块体滑动的"解耦层",也没有考虑到刚性块体变形中的断裂相互作用.本文建立了包含相互平行的龙门山断裂与龙日坝断裂的刚性上地壳模型,用极薄的低阻低速层作为块体滑动的解耦带,采用速率相关的非线性摩擦接触有限元方法,基于R最小策略控制时间步长,计算了在仅有侧向挤压力作用下,低阻低速层对青藏高原东缘的刚性块体变形和断裂活动的作用.计算结果显示,低阻低速层控制了刚性块体的垂直变形和水平变形分布特征.在侧向挤压力的持续作用下,在低阻低速层控制下的巴颜喀拉块体能够快速隆升,而缺乏低阻低速层的四川盆地隆升速度和隆升量均极小,隆升差异集中在龙门山断裂附近,使其发生应力积累乃至破裂.龙日坝断裂被两侧的刚性次级块体挟持着一起向南东方向运动,但该断裂的走滑运动分解了绝大部分施加在块体边界上的走滑量,使得相邻的龙门山次级块体的走滑分量遽然减少,也使得龙门山断裂表现出以逆冲为主,兼有少量走滑的运动性质.本文所得的这些计算结果显示了在缺乏中下地壳流,仅在低阻低速层解耦下刚性块体隆升过程及相关断裂活动,提供了青藏高原东缘刚性块体挤出的可行性,为青藏高原东缘隆升机制的研究讨论提供了重要依据. 展开更多
关键词 青藏高原东缘 低阻低速层 有限元 龙门山断裂 龙日坝断裂
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地震发生过程的有限单元法模拟--以苏门答腊俯冲带上的大地震为例 被引量:36
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作者 朱守彪 邢会林 +1 位作者 谢富仁 石耀霖 《地球物理学报》 SCIE EI CAS CSCD 北大核心 2008年第2期460-468,共9页
地震预报由目前的经验预报走向物理预报,数值模拟地震过程是其中的关键.文中应用统一的数学公式表述了速率相关的摩擦接触中黏着(sticking)和滑移(sliding)这两种不同的运动状态;有限元计算中采用静力显示的时间积分方法,基于R最小策略... 地震预报由目前的经验预报走向物理预报,数值模拟地震过程是其中的关键.文中应用统一的数学公式表述了速率相关的摩擦接触中黏着(sticking)和滑移(sliding)这两种不同的运动状态;有限元计算中采用静力显示的时间积分方法,基于R最小策略,控制时间步长以保持力学状态变化稳定,从而保证有限元计算过程平稳、收敛.以2004年发生过Mm=9.3特大地震的苏门答腊俯冲带为例,模拟了俯冲带上俯冲板片与上伏板块之间的闭锁、解锁、滑动到再闭锁这一准周期性过程,即地震的孕育、发生过程.计算结果表明,俯冲带上具有较大尺度、介质均匀、摩擦系数相同的区域是产生大规模、大幅度整体突然滑动(即大地震)的条件;模拟的苏门答腊俯冲带上的大地震在时间上有准周期性,空间上有迁移特征,破裂由深部向浅部进行;此外,俯冲带的几何特征对大地震的震源位置有很大的影响. 展开更多
关键词 有限单元 摩擦接触 地震 苏门答腊俯冲带
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断裂两盘岩性差异对汶川地震的影响 被引量:13
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作者 姚琪 邢会林 +1 位作者 徐锡伟 张微 《地球物理学报》 SCIE EI CAS CSCD 北大核心 2012年第11期3634-3647,共14页
岩性差异导致层间变形差异是常见的构造变形现象.龙门山断裂带中段北川—映秀断裂虹口至清平段,断裂上盘为坚硬的前震旦系褶皱基底,下盘则为软弱的前陆盆地沉积物,两者之间具有较大的岩性差异.本文利用基于R-minimum的有限元算法对在一... 岩性差异导致层间变形差异是常见的构造变形现象.龙门山断裂带中段北川—映秀断裂虹口至清平段,断裂上盘为坚硬的前震旦系褶皱基底,下盘则为软弱的前陆盆地沉积物,两者之间具有较大的岩性差异.本文利用基于R-minimum的有限元算法对在一个地震复发间隔内的断层活动进行非线性摩擦接触模拟.计算结果显示,上下盘泊松比的差异则对断层破裂时间及快体变形影响不大,但不同的泊松比条件下断层的破裂过程略有不同,而上下盘杨氏模量的差异能够延迟断层的破裂时间,延长破裂过程,扩大地震复发间隔,且扩大了下盘深度10km以上和10km以下地层变形的差异.双断坡构造能够通过深部的应力分解来削弱断层下盘深度10km以上的变形,但是在上下盘岩性一致的情况下,双断坡构造推迟了主断层的滑动时间,延长了破裂过程,而在强硬上盘和软弱下盘共存的条件下,发育于软弱下盘的次级破裂并不能对主断层的破裂时间和破裂过程造成较大影响.北川—映秀断裂上盘强硬的彭灌杂岩和下盘软弱的含碳沉积地层对汶川地震双断坡式破裂的生成具有重要的促进作用. 展开更多
关键词 龙门山断裂带 汶川地震 杨氏模量 泊松比 摩擦接触
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共轭断层系统的非线性有限元模拟与震群模型讨论 被引量:6
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作者 郭婷婷 徐锡伟 +1 位作者 邢会林 于贵华 《地震地质》 EI CSCD 北大核心 2015年第2期598-612,共15页
采用断层摩擦接触的非线性有限元模拟方法,对单断层与交叉断层2种断层模型分别进行数值模拟计算对比,结合中国大陆双震或震群型地震孕育发生的构造条件对共轭断层系统的孕震与发震机理进行了讨论与分析。断面滑动摩擦机制较好地解释了... 采用断层摩擦接触的非线性有限元模拟方法,对单断层与交叉断层2种断层模型分别进行数值模拟计算对比,结合中国大陆双震或震群型地震孕育发生的构造条件对共轭断层系统的孕震与发震机理进行了讨论与分析。断面滑动摩擦机制较好地解释了共轭断层由闭锁状态进入发生地震的滑动状态的过程,共轭断层系统会交替地发生失稳事件,验证了2组共轭断层系统构成的地震模型的滑动习性。其数值模拟与讨论分析结果可为共轭断层发育区的地震监测预报提供科学依据。 展开更多
关键词 共轭断层系统 地震构造模型 摩擦接触 非线性有限元模拟
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2015年尼泊尔地震三维发震构造及地震危险性研究 被引量:2
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作者 姚琪 徐锡伟 +5 位作者 邢会林 程佳 江国焰 马未宇 刘杰 杨文 《地球物理学报》 SCIE EI CAS CSCD 北大核心 2018年第6期2332-2343,共12页
2015年4月25日尼泊尔M_W7.8地震发生在喜马拉雅造山带上,人们普遍认为该地震不足以释放该造山带上累积的能量,但对该地区后续地震危险性评价多基于二维或是假三维的形变反演计算结果.本研究从2015年尼泊尔地震主震与其最大余震M_W7.3地... 2015年4月25日尼泊尔M_W7.8地震发生在喜马拉雅造山带上,人们普遍认为该地震不足以释放该造山带上累积的能量,但对该地区后续地震危险性评价多基于二维或是假三维的形变反演计算结果.本研究从2015年尼泊尔地震主震与其最大余震M_W7.3地震之间的关系出发,着重分析讨论了尼泊尔地震的时间和空间的非均匀性,结合震源机制解、地壳速度结构、精定位后的余震分布及InSAR反演结果,建立了三维发震构造模型,利用非线性摩擦有限元方法,对一个地震周期内断层摩擦行为和块体变形进行了模拟,将计算结果和地表同震形变、形变反演的同震破裂、历史地震时空演化进行对比,在确认该三维模型可靠性的基础上,讨论了该地区后续地震的可能位置,认为在1934年比哈—尼泊尔M_W^8.1地震以东区域,还存在发生大地震的可能,在最大余震M_W7.3地震东南部位,还存在发生中大地震的可能. 展开更多
关键词 2015尼泊尔地震 三维模型 走向不均匀 非线性摩擦 有限元方法 地震危险性
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Jini技术应用及其与EJB的比较 被引量:2
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作者 朱茜 陈福民 徐冰 《微型电脑应用》 2001年第6期57-59,共3页
本文在研究分布式计算必要性的基础上 ,通过对 Jini结构牲特征的探讨 ,比较了 Jini和 EJB的异同点 。
关键词 分布式计算 JAVA Jini EJB INTERNET
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Decomposition and Evolution of Intracontinental Strike-Slip Faults in Eastern Tibetan Plateau 被引量:8
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作者 YAO Qi XU Xiwei +2 位作者 XING Huilin XU Chong WANG Xiaohui 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2013年第2期304-317,共14页
Little attention had been paid to the intracontinental strike-slip faults of the Tibetan Plateau. Since the discovery of the Longriba fault using re-measured GPS data in 2003, an increasing amount of attention has bee... Little attention had been paid to the intracontinental strike-slip faults of the Tibetan Plateau. Since the discovery of the Longriba fault using re-measured GPS data in 2003, an increasing amount of attention has been paid to this neglected fault. The local relief and transverse swath profile show that the Longriba fault is the boundary line that separates the high and flat tomography of the Tibet plateau from the high and precipitous tomography of Orogen. In addition, GPS data shows that the Longriba fault is the boundary line where the migratory direction of the Bayan Har block changed from eastward to southeastward. The GPS data shows that the Longriba fault is the boundary fault of the sub-blocks of the eastern Bayan Har block. We built three-dimensional models containing the Longriba fault and the middle segment of the Longmenshan fault, across the Bayan Har block and the Sichuan Basin. A nonlinear finite element method was used to simulate the fault behavior and the block deformation of the Eastern Tibetan Plateau. The results show that the low resistivity and low velocity layer acts as a detachment layer, which causes the overlying blocks to move southeastward. The detachment layer also controls the vertical and horizontal deformation of the rigid Bayan Har block and leads to accumulation strain on the edge of the layer where the Longmenshan thrust is located. After a sufficient amount of strain has been accumulated on the Longmenshan fault, a large earthquake occurs, such as the 2008 Wenchuan earthquake. The strike slip activity of the Longriba fault, which is above the low resistivity and low velocity layer, partitions the lateral displacements of the Bayan Har block and adjusts the direction of motion of the Bayan Har block, from the eastward moving Ahba sub-block in the west to southeastward moving Longmenshan sub-block in the east. Four models with different depths to the Longriba fault were constructed: (1) a shallow fault with a depth of only 4 km, (2) a deeper fault that is half as deep as the Longmenshan fault, (3) a deep fault that is 2 km shallower than the low resistivity and low velocity layer, and (4) a fault that is as deep as the low resistivity and low velocity layer. The activity and influence of the Longriba fault with different development stage under this tectonic system were shown: in one Earthquake recurrence period, the rupture region of the fault increases with the depth of the fault, and the lateral slip partition by the fault also changes with the fault depth. It suggests that the Longriba fault is a newly generated fault that developed after the quick uplift in Late Cenozoic along this tectonic setting and gradually extended from the northwest to southeast. The calculations provide the characteristic of block deformation and fault behaviors of intra-continental strike-slip fault and major boundary thrust faults in the eastern margin of the Tibet plateau. Although the low resistivity and low velocity layer controls the deformation of the Bayan Hat block and the uplift of the Longmenshan thrust, the partition of the Longriba fault has an important influence on the intra-plate deformation and modern geomorphic evolution. 展开更多
关键词 Bayan Har block Longmenshan thrust fault Longriba fault intracontinental fault nonlinear friction
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PARALLEL ANALYSIS OF COMBINED FINITE/DISCRETE ELEMENT SYSTEMS ON PC CLUSTER 被引量:5
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作者 王福军 Y.T.FENG +2 位作者 D.R.J.OWEN 张静 刘洋 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2004年第5期534-540,共7页
A computational strategy is presented for the nonlinear dynamic analysis of large- scale combined finite/discrete element systems on a PC cluster.In this strategy,a dual-level domain decomposition scheme is adopted to... A computational strategy is presented for the nonlinear dynamic analysis of large- scale combined finite/discrete element systems on a PC cluster.In this strategy,a dual-level domain decomposition scheme is adopted to implement the dynamic domain decomposition.The domain decomposition approach perfectly matches the requirement of reducing the memory size per processor of the calculation.To treat the contact between boundary elements in neighbouring subdomains,the elements in a subdomain are classified into internal,interfacial and external elements.In this way,all the contact detect algorithms developed for a sequential computation could be adopted directly in the parallel computation.Numerical examples show that this implementation is suitable for simulating large-scale problems.Two typical numerical examples are given to demonstrate the parallel efficiency and scalability on a PC cluster. 展开更多
关键词 parallel computation finite element discrete element PC cluster
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LBM simulation of fluid flow in fractured porous media with permeable matrix 被引量:3
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作者 Jinfang Gao Huiling Xing 《Theoretical & Applied Mechanics Letters》 CAS 2012年第3期49-52,共4页
To analyze and depict complicated fluid behaviors in fractured porous media with variably permeable matrix,an integrated discrete computational algorithm is proposed based on lattice Boltzmann method(LBM).This paper... To analyze and depict complicated fluid behaviors in fractured porous media with variably permeable matrix,an integrated discrete computational algorithm is proposed based on lattice Boltzmann method(LBM).This paper combines with the external force model and statistical material physics to effectively describe the feature changes while the fluid passes through the fractures within the permeable matrix.As an application example,a two dimensional rock sample is reconstructed using the digital image and characterized with different feature values at each LBM grid to distinguish pores,impermeable and permeable matrix by stating its local physical property.Compared with the conventional LBM,the results demonstrate the advantages of proposed algorithm in modeling fluid flow phenomenon in fractured porous media with variably permeable matrix. 展开更多
关键词 fractured porous media fluid dynamics permeable matrix lattice Boltzmann
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Sounds Synthesis with Slime Mould of Physarum Polycephalum 被引量:2
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作者 Eduardo R. Miranda Andrew Adamatzky Jeff Jones 《Journal of Bionic Engineering》 SCIE EI CSCD 2011年第2期107-113,共7页
This paper introduces a novel application of bionic engineering: a bionic musical instrument using Physarum polycephalum. Physarum polycephalum is a huge single cell with thousands of nuclei, which behaves like a gia... This paper introduces a novel application of bionic engineering: a bionic musical instrument using Physarum polycephalum. Physarum polycephalum is a huge single cell with thousands of nuclei, which behaves like a giant amoeba. During its foraging behavior this plasmodium produces electrical activity corresponding to different physiological states. We developed a method to render sounds from such electrical activity and thus represent spatio-temporal behavior of slime mould in a form apprehended auditorily. The electrical activity is captured by various electrodes placed on a Petri dish containing the cultured slime mold. Sounds are synthesized by a bank of parallel sinusoidal oscillators connected to the electrodes. Each electrode is responsible for one partial of the spectrum of the resulting sound. The behavior of the slime mould can be controlled to produce different timbres. 展开更多
关键词 Physarum polycephalum bionic musical instrument unconventional computing sound synthesis SONIFICATION
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Interaction of cetyltrimethylammonium bromide with drug in aqueous/electrolyte solution:A combined conductometric and molecular dynamics method study 被引量:3
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作者 Md.Anamul Hoque Md.Masud Alam +5 位作者 Mohammad Robel Molla Shahed Rana Malik Abdul Rub Mohammad A.Halim Mohammed Abdullah Khan Farida Akhtar 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2018年第1期159-167,共9页
Interaction between beta-lactum antibiotic drug ciprofloxacin hydrochloride(CFH)and cationic surfactant cetyltrimethylammonium bromide(CTAB)was performed conductometrically in aqueous as well as in the occurrence of d... Interaction between beta-lactum antibiotic drug ciprofloxacin hydrochloride(CFH)and cationic surfactant cetyltrimethylammonium bromide(CTAB)was performed conductometrically in aqueous as well as in the occurrence of different salts(NaCl,KCl as well as NH_4Cl)over the temperature range of 298.15–323.15 K at the regular interval of 5 K.CFH drug has been suggested for the treatment of bacterial infections such as urinary tract infections and acute sinusitis.A clear critical micelle concentration(CMC)was obtained for pure CTAB as well as(CFH+CTAB)mixed systems.The decrease in CMC values of CTAB caused by the addition of CFH reveals the existence of the interaction between the components and therefore it is the indication of micelle formation at lower concentration of CTAB and their CMC values further decrease in attendance of salts.A nonlinear behavior in the CMC versus T plot was observed in all the cases.The ΔG_m^0 values are found to be negative in present study systems demonstrated the stability of the solution.The values of ΔH_m^0 and ΔS_m^0 reveal the existence of hydrophobic and electrostatic interactions between CFH and CTAB.The thermodynamic properties of transfer for the micellization were also evaluated and discussed in detail.Molecular dynamic simulation disclosed that environment of water and salts have impact on the hydrophobic interaction between CFH and CTAB.In water and salts,CTAB adopts spherical micelle in which charged hydrophilic groups are interacted with waters whereas hydrophobic tails form the core of the micelle.This hydrophobic core region is highly conserved and protected.In addition,micelle formation is more favorable in aqueous Na Cl solution than other solutions. 展开更多
关键词 相互作用 溴化物 动力学方法 电解质 学习 分子 尿道感染 表面活化剂
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