Video watermarking plays a crucial role in protecting intellectual property rights and ensuring content authenticity.This study delves into the integration of Galois Field(GF)multiplication tables,especially GF(2^(4))...Video watermarking plays a crucial role in protecting intellectual property rights and ensuring content authenticity.This study delves into the integration of Galois Field(GF)multiplication tables,especially GF(2^(4)),and their interaction with distinct irreducible polynomials.The primary aim is to enhance watermarking techniques for achieving imperceptibility,robustness,and efficient execution time.The research employs scene selection and adaptive thresholding techniques to streamline the watermarking process.Scene selection is used strategically to embed watermarks in the most vital frames of the video,while adaptive thresholding methods ensure that the watermarking process adheres to imperceptibility criteria,maintaining the video's visual quality.Concurrently,careful consideration is given to execution time,crucial in real-world scenarios,to balance efficiency and efficacy.The Peak Signal-to-Noise Ratio(PSNR)serves as a pivotal metric to gauge the watermark's imperceptibility and video quality.The study explores various irreducible polynomials,navigating the trade-offs between computational efficiency and watermark imperceptibility.In parallel,the study pays careful attention to the execution time,a paramount consideration in real-world scenarios,to strike a balance between efficiency and efficacy.This comprehensive analysis provides valuable insights into the interplay of GF multiplication tables,diverse irreducible polynomials,scene selection,adaptive thresholding,imperceptibility,and execution time.The evaluation of the proposed algorithm's robustness was conducted using PSNR and NC metrics,and it was subjected to assessment under the impact of five distinct attack scenarios.These findings contribute to the development of watermarking strategies that balance imperceptibility,robustness,and processing efficiency,enhancing the field's practicality and effectiveness.展开更多
Among the bamboo slips dating to the Warring States period(475-221 BCE),stored at Tsinghua University,there is an aggregate of 21 specially shaped slips that are painted with red lines on the obverse side.Numbers are ...Among the bamboo slips dating to the Warring States period(475-221 BCE),stored at Tsinghua University,there is an aggregate of 21 specially shaped slips that are painted with red lines on the obverse side.Numbers are written on 20 slips in accordance with certain rules,and on one slip without numbers there are 20 round holes and residues of ribbon.These slips,after being compiled as a whole,serve as a practical calculator in the form of a table,which is designated as Suan Biao算表(the multiplication table).In this paper,the structure and functions of the Suan Biao are discussed by comparing it with other ancient multiplication tables.Specifically,it is noted that the core of the Suan Biao is a multiplication table comprising the numbers 9 to 1 and their products 81 to 1;the other parts are an extension of the core.The Suan Biao employs the decimal place value system and manifested the author’s knowledge of the commutative law of multiplication,the distributive law of multiplication over addition,and fractions.Not only is this table directly applicable to the multiplication of two-digit numbers,but also to division.In addition,certain computations regarding 1/2 or fractions containing 1/2 can be conducted using this table,and it may also be used for extracting roots.The Suan Biao is of great significance for research on ancient mathematics,and its discovery is enormously valuable for studies on arithmetic methods and computational tools in early China.展开更多
In order to study the infl uence of the ground motion spatial eff ect on the seismic response of large span spatial structures with isolation bearings, a single-layer cylindrical latticed shell scale model with a simi...In order to study the infl uence of the ground motion spatial eff ect on the seismic response of large span spatial structures with isolation bearings, a single-layer cylindrical latticed shell scale model with a similarity ratio of 1/10 was constructed. An earthquake simulation shaking table test on the response under multiple-support excitations was performed with the high-position seismic isolation method using high damping rubber (HDR) bearings. Small-amplitude sinusoidal waves and seismic wave records with various spectral characteristics were applied to the model. The dynamic characteristics of the model and the seismic isolation eff ect on it were analyzed at varying apparent wave velocities, namely infi nitely great, 1000 m/s, 500 m/s and 250 m/s. Besides, numerical simulations were carried out by Matlab software. According to the comparison results, the numerical results agreed well with the experimental data. Moreover, the results showed that the latticed shell roof exhibited a translational motion as a rigid body after the installation of the HDR bearings with a much lower natural frequency, higher damping ratio and only 1/2~1/8 of the acceleration response peak values. Meanwhile, the structural responses and the bearing deformations at the output end of the seismic waves were greatly increased under multiple-support excitations.展开更多
Porcelain electrical equipment （PEE）, such as current transformers, is critical to power supply systems, but its seismic performance during past earthquakes has not been satisfactory. This paper studies the seismic ...Porcelain electrical equipment （PEE）, such as current transformers, is critical to power supply systems, but its seismic performance during past earthquakes has not been satisfactory. This paper studies the seismic performance of two typical types of PEE and proposes a damping method for PEE based on multiple tuned mass dampers （MTMD）. An MTMD damping device involving three mass units, named a triple tuned mass damper （TTMD）, is designed and manufactured. Through shake table tests and finite element analysis, the dynamic characteristics of the PEE are studied and the effectiveness of the MTMD damping method is verified. The adverse influence of MTMD redundant mass to damping efficiency is studied and relevant equations are derived. MTMD robustness is verified through adjusting TTMD control frequencies. The damping effectiveness of TTMD, when the peak ground acceleration far exceeds the design value, is studied. Both shake table tests and finite element analysis indicate that MTMD is effective and robust in attenuating PEE seismic responses. TTMD remains effective when the PGA far exceeds the design value and when control deviations are considered.展开更多
面向大规模机械装备监测数据管理中遇到的海量数据存储、快速读写响应、大规模数据分析等难题,提出使用基于NoSQL(Not only SQL)的LaUD-MS系统进行监测数据管理的存储架构。设计一种多列族自由表模型,并通过理论和实验对其读写性能进行...面向大规模机械装备监测数据管理中遇到的海量数据存储、快速读写响应、大规模数据分析等难题,提出使用基于NoSQL(Not only SQL)的LaUD-MS系统进行监测数据管理的存储架构。设计一种多列族自由表模型,并通过理论和实验对其读写性能进行分析对比,证明了本存储方案能够解决海量监测数据的存储难题,并满足面向维护、维修和大修服务的查询需求。展开更多
文摘Video watermarking plays a crucial role in protecting intellectual property rights and ensuring content authenticity.This study delves into the integration of Galois Field(GF)multiplication tables,especially GF(2^(4)),and their interaction with distinct irreducible polynomials.The primary aim is to enhance watermarking techniques for achieving imperceptibility,robustness,and efficient execution time.The research employs scene selection and adaptive thresholding techniques to streamline the watermarking process.Scene selection is used strategically to embed watermarks in the most vital frames of the video,while adaptive thresholding methods ensure that the watermarking process adheres to imperceptibility criteria,maintaining the video's visual quality.Concurrently,careful consideration is given to execution time,crucial in real-world scenarios,to balance efficiency and efficacy.The Peak Signal-to-Noise Ratio(PSNR)serves as a pivotal metric to gauge the watermark's imperceptibility and video quality.The study explores various irreducible polynomials,navigating the trade-offs between computational efficiency and watermark imperceptibility.In parallel,the study pays careful attention to the execution time,a paramount consideration in real-world scenarios,to strike a balance between efficiency and efficacy.This comprehensive analysis provides valuable insights into the interplay of GF multiplication tables,diverse irreducible polynomials,scene selection,adaptive thresholding,imperceptibility,and execution time.The evaluation of the proposed algorithm's robustness was conducted using PSNR and NC metrics,and it was subjected to assessment under the impact of five distinct attack scenarios.These findings contribute to the development of watermarking strategies that balance imperceptibility,robustness,and processing efficiency,enhancing the field's practicality and effectiveness.
文摘Among the bamboo slips dating to the Warring States period(475-221 BCE),stored at Tsinghua University,there is an aggregate of 21 specially shaped slips that are painted with red lines on the obverse side.Numbers are written on 20 slips in accordance with certain rules,and on one slip without numbers there are 20 round holes and residues of ribbon.These slips,after being compiled as a whole,serve as a practical calculator in the form of a table,which is designated as Suan Biao算表(the multiplication table).In this paper,the structure and functions of the Suan Biao are discussed by comparing it with other ancient multiplication tables.Specifically,it is noted that the core of the Suan Biao is a multiplication table comprising the numbers 9 to 1 and their products 81 to 1;the other parts are an extension of the core.The Suan Biao employs the decimal place value system and manifested the author’s knowledge of the commutative law of multiplication,the distributive law of multiplication over addition,and fractions.Not only is this table directly applicable to the multiplication of two-digit numbers,but also to division.In addition,certain computations regarding 1/2 or fractions containing 1/2 can be conducted using this table,and it may also be used for extracting roots.The Suan Biao is of great significance for research on ancient mathematics,and its discovery is enormously valuable for studies on arithmetic methods and computational tools in early China.
基金National Natural Science Foundation of China under Grant No.51278008the National Key Research and Development Plan of China under Grant No.2016YFC0701103
文摘In order to study the infl uence of the ground motion spatial eff ect on the seismic response of large span spatial structures with isolation bearings, a single-layer cylindrical latticed shell scale model with a similarity ratio of 1/10 was constructed. An earthquake simulation shaking table test on the response under multiple-support excitations was performed with the high-position seismic isolation method using high damping rubber (HDR) bearings. Small-amplitude sinusoidal waves and seismic wave records with various spectral characteristics were applied to the model. The dynamic characteristics of the model and the seismic isolation eff ect on it were analyzed at varying apparent wave velocities, namely infi nitely great, 1000 m/s, 500 m/s and 250 m/s. Besides, numerical simulations were carried out by Matlab software. According to the comparison results, the numerical results agreed well with the experimental data. Moreover, the results showed that the latticed shell roof exhibited a translational motion as a rigid body after the installation of the HDR bearings with a much lower natural frequency, higher damping ratio and only 1/2~1/8 of the acceleration response peak values. Meanwhile, the structural responses and the bearing deformations at the output end of the seismic waves were greatly increased under multiple-support excitations.
基金Scientific Research Fund of IEM,CEA under Grant Nos.2016B09,2014B12China Natural Science Foundation under Grant Nos.51478442,51408565
文摘Porcelain electrical equipment （PEE）, such as current transformers, is critical to power supply systems, but its seismic performance during past earthquakes has not been satisfactory. This paper studies the seismic performance of two typical types of PEE and proposes a damping method for PEE based on multiple tuned mass dampers （MTMD）. An MTMD damping device involving three mass units, named a triple tuned mass damper （TTMD）, is designed and manufactured. Through shake table tests and finite element analysis, the dynamic characteristics of the PEE are studied and the effectiveness of the MTMD damping method is verified. The adverse influence of MTMD redundant mass to damping efficiency is studied and relevant equations are derived. MTMD robustness is verified through adjusting TTMD control frequencies. The damping effectiveness of TTMD, when the peak ground acceleration far exceeds the design value, is studied. Both shake table tests and finite element analysis indicate that MTMD is effective and robust in attenuating PEE seismic responses. TTMD remains effective when the PGA far exceeds the design value and when control deviations are considered.
文摘面向大规模机械装备监测数据管理中遇到的海量数据存储、快速读写响应、大规模数据分析等难题,提出使用基于NoSQL(Not only SQL)的LaUD-MS系统进行监测数据管理的存储架构。设计一种多列族自由表模型,并通过理论和实验对其读写性能进行分析对比,证明了本存储方案能够解决海量监测数据的存储难题,并满足面向维护、维修和大修服务的查询需求。
