A wavelet method of detection and estimation of change points in nonparametric regression models under random design is proposed. The confidence bound of our test is derived by using the test statistics based on empir...A wavelet method of detection and estimation of change points in nonparametric regression models under random design is proposed. The confidence bound of our test is derived by using the test statistics based on empirical wavelet coefficients as obtained by wavelet transformation of the data which is observed with noise. Moreover, the consistence of the test is proved while the rate of convergence is given. The method turns out to be effective after being tested on simulated examples and applied to IBM stock market data.展开更多
Some representative working conditions were measured, and the amplitude distribution rule of each representative working condition after analysis of measured data was got. The building of 2 D distributing function be...Some representative working conditions were measured, and the amplitude distribution rule of each representative working condition after analysis of measured data was got. The building of 2 D distributing function between the range and the mean of random load was discussed. Experiment was carried out to get the fatigue strength data of the material of transmission component. Accessing the P S a S m N camber of combined load of bending and torsion on this material after analysis. And the process of calculating the 2 D fatigue life in multi working condition was discussed.展开更多
Based on probability and statistic, a design method of precision cam profileconcerning the influence of random processing errors is advanced. Combining the design with theprocess, which can be used to predict that cam...Based on probability and statistic, a design method of precision cam profileconcerning the influence of random processing errors is advanced. Combining the design with theprocess, which can be used to predict that cam profiles will be successfully processed or not in thedesign stage, design of the cam can be done by balancing the economization and reliability. Inaddition, an fuzzy deduction method based on Bayers formula is advanced to estimate processingreasonable of the designed precision cam profile, and it take few samples.展开更多
In this paper, we re-formalize the security notions of universal designated multi verifier signature （UDMVS） schemes. Then the first UDMVS scheme is presented in the standard model （i.e. without random oracles） ba...In this paper, we re-formalize the security notions of universal designated multi verifier signature （UDMVS） schemes. Then the first UDMVS scheme is presented in the standard model （i.e. without random oracles） based on Waters＇ signature scheme. In this setting, a signature holder can to designate the signature to multi verifiers. Moreover, the security of our proposed scheme is based on the Gap Bilinear Difffie-Hellman assumption.展开更多
Clear effects criterion is an important criterion for selecting fractional factorial designs[1].Tang et al.[2]derived upper and lower bounds on the maximum number of clear two-factor interactions（2fi＇s）in 2^n-（n-k...Clear effects criterion is an important criterion for selecting fractional factorial designs[1].Tang et al.[2]derived upper and lower bounds on the maximum number of clear two-factor interactions（2fi＇s）in 2^n-（n-k）designs of resolution Ⅲ and Ⅳ by constructing 2^n-（n-k）designs.But the method in[2]does not perform well sometimes when the resolution is Ⅲ.This article modifies the construction method for 2^n-（n-k） designs of resolution Ⅲ in[2].The modified method is a great improvement on that used in[2].展开更多
Spacecraft in the aerospace field and military equipment in the military field are at risk of being impacted by external objects,which can cause local damage to the structure.The randomness of local damage is a newcha...Spacecraft in the aerospace field and military equipment in the military field are at risk of being impacted by external objects,which can cause local damage to the structure.The randomness of local damage is a newchallenge for structural design,and it is essential to take random damage into account in the conceptual design phase for the purpose of improving structure’s resistance to external shocks.In this article,a random damaged structure is assumed to have damages of the same size and shape at random locations,and the random damage is considered as multiple damage conditions of the structure.In order to improve the randomness and comprehensiveness of the multiple damage conditions,the stacking strategy is used to generate the distribution of the damage area.Following this strategy,the topology optimization design of the random damaged structure,which is to minimize the weight of the structure with a constraint on the stress of the structure under multiple damage conditions,is formulated based on the independent continuousmapping(ICM)method.The dual sequence quadratic programming(DSQP)algorithm combined with the stress globalization method is adopted to solve the optimization problem.The numerical examples demonstrate the effectiveness and applicability of the proposed method in the topology optimization of strength-safe continuum structures.展开更多
Fe-Ni-Cr-based super-high-strength maraging stainless steels were generally realized by multiple-element alloying under a given heat treatment processing. A series of alloy compositions were designed with a uniform cl...Fe-Ni-Cr-based super-high-strength maraging stainless steels were generally realized by multiple-element alloying under a given heat treatment processing. A series of alloy compositions were designed with a uniform cluster formula of [Ni16Fe192]（Cr32（Ni16-x-y-z-m-n MoxTiyNbzAlmVn）） （at.%） that was developed out of a unique alloy design tool, a cluster- plus-glue-atom model. Alloy rods with a diameter of 6 mm were prepared by copper-mold suction-cast processing under the argon atmosphere. These alloy samples were solid-solutioned at 1273 K for 1 h, followed by water-quenching, and then aged at 783 K for 3 h. The effect of the valence electron concentration, characterized with the number of valence electrons per unit cluster （VE/uc） formula of 16 atoms, on microhardness of these designed maraging stainless steels at both solid- solutioned and aged states was investigated. The relationship between alloy compositions and microhardness in maraging stainless steels was firstly established by the random forest （RF, a kind of machine learning methods） based on the experimental results. It was found that not only the microhardness of any given composition alloy within the frame of cluster formula, but also the alloy composition with a maximum microhardness for any given VE/uc, could be predicted in good agreement with the guidance of the relationship by RF. The contributions of minor-alloying elements to the microhardness of the aged alloys were also discussed.展开更多
Cutterhead loads are the key mechanical parameters for the strength design of the full face hard rock tunnel boring machine(TBM).Due to the brittle rock-breaking mechanism,the excavation loads acting on cutters fluctu...Cutterhead loads are the key mechanical parameters for the strength design of the full face hard rock tunnel boring machine(TBM).Due to the brittle rock-breaking mechanism,the excavation loads acting on cutters fluctuate strongly and show some randomness.The conventional method that using combinations of some special static loads to perform the strength design of TBM cutterhead may lead to strength failure during working practice.In this paper,a three-dimensional finite element model for coupled Cutterhead–Rock is developed to determine the cutterhead loads.Then the distribution characteristics and the influence factors of cutterhead loads are analyzed based on the numerical results.It is found that,as time changes,the normal and tangential forces acting on cutters and the total torque acting on the cutterhead approximately distribute log normally,while the total thrusts acting on the cutterhead approximately show a normal distribution.Furthermore,the statistical average values of cutterhead loads are proportional to the uniaxial compressive strength(UCS)of cutting rocks.The values also change with the penetration and the diameter of cutterhead following a power function.Based on these findings,we propose a three-parameter model for the mean of cutterhead loads and a method of generating the random cutter forces.Then the strength properties of a typical cutterhead are analyzed in detail using loads generated by the new method.The optimized cutterhead has been successfully applied in engineering.The method in this paper may provide a useful reference for the strength design of TBM cutterhead.展开更多
Reliability optimal design is an integrated approach widely adopted in engineering. The fuze components are designed by a BP neural network combined with an optimal design approach based on their multi-failure modes. ...Reliability optimal design is an integrated approach widely adopted in engineering. The fuze components are designed by a BP neural network combined with an optimal design approach based on their multi-failure modes. Their reliability probabilities in multi-failure modes are transformed into deterministic design parameters. The designed results by an example of optimizing the fuze spring under a certain reliability show that the integrated approach is practical and efficient.展开更多
An approach to design small scale CMOS static random access memory (SRAM) is proposed. The design of address decoder, memory cell, and the layout are included. This approach adopts flip-flop array structure. The flip-...An approach to design small scale CMOS static random access memory (SRAM) is proposed. The design of address decoder, memory cell, and the layout are included. This approach adopts flip-flop array structure. The flip-flops are used as the storage cells and they are stacked to form the whole SRAM module. The word select bit is generated from the address decoder. And one word at a time is selected for reading or writing. The design of the memory core's layout is also discussed since it should be optimized to save area and also should be convenient for realization. It's a full-custom layout. The address decoder is composed of combinational logic circuit and its layout is also designed as a full-custom layout. With all these modules, the integral structure of the SRAM is carried out.展开更多
[目的]系统梳理口服中药治疗支气管扩张症(简称“支扩”)随机对照试验(RCT)的文献特征及结局指标现状,为提高临床研究质量及构建核心指标集提供参考。[方法]计算机检索PubMed、Embase、Cochrane Library、Web of Science、中国知网(CNKI...[目的]系统梳理口服中药治疗支气管扩张症(简称“支扩”)随机对照试验(RCT)的文献特征及结局指标现状,为提高临床研究质量及构建核心指标集提供参考。[方法]计算机检索PubMed、Embase、Cochrane Library、Web of Science、中国知网(CNKI)、万方数据知识服务平台(Wangfang Database)、维普网(VIP)及中国生物医学文献服务系统(SinoMed)数据库中口服中药治疗支扩RCT相关文献,检索时间为2019年1月1日—2024年7月31日,提取基本信息、文献特征、结局指标等进行统计分析。[结果]共纳入117篇文献、9733例患者。1项为多中心研究,汤剂为最常用剂型,干预疗程多集中于8 d~2周,15篇文献提及随访,94篇文献报告患者中医证型。共得到106种结局指标,可归为9个指标域,总报告频次为889次,报告率前10位的指标依次是:有效率、不良反应、第1秒用力呼气容积(FEV1)、中医证候积分、C反应蛋白(CRP)、白细胞计数、用力肺活量(FVC)、FEV1/FVC、降钙素原(PCT)、中医症状积分。[结论]近5年口服中药治疗支扩RCT在研究方案设计及结局指标报告方面存在病例代表性差、疗程短、随访率低、辨证参考标准不一、结局指标应用不规范等诸多问题,未来仍需更多高质量RCT,同时需构建中医药治疗支扩核心指标集,以提高中医药循证证据质量。展开更多
基金the National Natural Science Foundation of China （No. 60375003） the Astronautics Basal Science Foundation of China （No. 03153059）.
文摘A wavelet method of detection and estimation of change points in nonparametric regression models under random design is proposed. The confidence bound of our test is derived by using the test statistics based on empirical wavelet coefficients as obtained by wavelet transformation of the data which is observed with noise. Moreover, the consistence of the test is proved while the rate of convergence is given. The method turns out to be effective after being tested on simulated examples and applied to IBM stock market data.
文摘Some representative working conditions were measured, and the amplitude distribution rule of each representative working condition after analysis of measured data was got. The building of 2 D distributing function between the range and the mean of random load was discussed. Experiment was carried out to get the fatigue strength data of the material of transmission component. Accessing the P S a S m N camber of combined load of bending and torsion on this material after analysis. And the process of calculating the 2 D fatigue life in multi working condition was discussed.
基金This project is supported by Significant Project Foundation of National 863 Program, China.
文摘Based on probability and statistic, a design method of precision cam profileconcerning the influence of random processing errors is advanced. Combining the design with theprocess, which can be used to predict that cam profiles will be successfully processed or not in thedesign stage, design of the cam can be done by balancing the economization and reliability. Inaddition, an fuzzy deduction method based on Bayers formula is advanced to estimate processingreasonable of the designed precision cam profile, and it take few samples.
基金Supported by the National Natural Science Foundation of China (60772136)
文摘In this paper, we re-formalize the security notions of universal designated multi verifier signature （UDMVS） schemes. Then the first UDMVS scheme is presented in the standard model （i.e. without random oracles） based on Waters＇ signature scheme. In this setting, a signature holder can to designate the signature to multi verifiers. Moreover, the security of our proposed scheme is based on the Gap Bilinear Difffie-Hellman assumption.
基金NNSF of China(10571093,10671099 and 10771123)SRFDP of China(20050055038)+1 种基金NSF of Shandong Province of China(Q2007A05)the Visiting Scholar Program at Chern Institute of Mathematics
文摘Clear effects criterion is an important criterion for selecting fractional factorial designs[1].Tang et al.[2]derived upper and lower bounds on the maximum number of clear two-factor interactions（2fi＇s）in 2^n-（n-k）designs of resolution Ⅲ and Ⅳ by constructing 2^n-（n-k）designs.But the method in[2]does not perform well sometimes when the resolution is Ⅲ.This article modifies the construction method for 2^n-（n-k） designs of resolution Ⅲ in[2].The modified method is a great improvement on that used in[2].
基金supported by the National Natural Science Foundation of China (Grant 11872080).
文摘Spacecraft in the aerospace field and military equipment in the military field are at risk of being impacted by external objects,which can cause local damage to the structure.The randomness of local damage is a newchallenge for structural design,and it is essential to take random damage into account in the conceptual design phase for the purpose of improving structure’s resistance to external shocks.In this article,a random damaged structure is assumed to have damages of the same size and shape at random locations,and the random damage is considered as multiple damage conditions of the structure.In order to improve the randomness and comprehensiveness of the multiple damage conditions,the stacking strategy is used to generate the distribution of the damage area.Following this strategy,the topology optimization design of the random damaged structure,which is to minimize the weight of the structure with a constraint on the stress of the structure under multiple damage conditions,is formulated based on the independent continuousmapping(ICM)method.The dual sequence quadratic programming(DSQP)algorithm combined with the stress globalization method is adopted to solve the optimization problem.The numerical examples demonstrate the effectiveness and applicability of the proposed method in the topology optimization of strength-safe continuum structures.
文摘Fe-Ni-Cr-based super-high-strength maraging stainless steels were generally realized by multiple-element alloying under a given heat treatment processing. A series of alloy compositions were designed with a uniform cluster formula of [Ni16Fe192]（Cr32（Ni16-x-y-z-m-n MoxTiyNbzAlmVn）） （at.%） that was developed out of a unique alloy design tool, a cluster- plus-glue-atom model. Alloy rods with a diameter of 6 mm were prepared by copper-mold suction-cast processing under the argon atmosphere. These alloy samples were solid-solutioned at 1273 K for 1 h, followed by water-quenching, and then aged at 783 K for 3 h. The effect of the valence electron concentration, characterized with the number of valence electrons per unit cluster （VE/uc） formula of 16 atoms, on microhardness of these designed maraging stainless steels at both solid- solutioned and aged states was investigated. The relationship between alloy compositions and microhardness in maraging stainless steels was firstly established by the random forest （RF, a kind of machine learning methods） based on the experimental results. It was found that not only the microhardness of any given composition alloy within the frame of cluster formula, but also the alloy composition with a maximum microhardness for any given VE/uc, could be predicted in good agreement with the guidance of the relationship by RF. The contributions of minor-alloying elements to the microhardness of the aged alloys were also discussed.
基金Supported by National Basic Research Program of China(973 Program,Grant No.2013CB035042)the National Natural Science Foundation of China(Grant No.11672202)
文摘Cutterhead loads are the key mechanical parameters for the strength design of the full face hard rock tunnel boring machine(TBM).Due to the brittle rock-breaking mechanism,the excavation loads acting on cutters fluctuate strongly and show some randomness.The conventional method that using combinations of some special static loads to perform the strength design of TBM cutterhead may lead to strength failure during working practice.In this paper,a three-dimensional finite element model for coupled Cutterhead–Rock is developed to determine the cutterhead loads.Then the distribution characteristics and the influence factors of cutterhead loads are analyzed based on the numerical results.It is found that,as time changes,the normal and tangential forces acting on cutters and the total torque acting on the cutterhead approximately distribute log normally,while the total thrusts acting on the cutterhead approximately show a normal distribution.Furthermore,the statistical average values of cutterhead loads are proportional to the uniaxial compressive strength(UCS)of cutting rocks.The values also change with the penetration and the diameter of cutterhead following a power function.Based on these findings,we propose a three-parameter model for the mean of cutterhead loads and a method of generating the random cutter forces.Then the strength properties of a typical cutterhead are analyzed in detail using loads generated by the new method.The optimized cutterhead has been successfully applied in engineering.The method in this paper may provide a useful reference for the strength design of TBM cutterhead.
文摘Reliability optimal design is an integrated approach widely adopted in engineering. The fuze components are designed by a BP neural network combined with an optimal design approach based on their multi-failure modes. Their reliability probabilities in multi-failure modes are transformed into deterministic design parameters. The designed results by an example of optimizing the fuze spring under a certain reliability show that the integrated approach is practical and efficient.
文摘An approach to design small scale CMOS static random access memory (SRAM) is proposed. The design of address decoder, memory cell, and the layout are included. This approach adopts flip-flop array structure. The flip-flops are used as the storage cells and they are stacked to form the whole SRAM module. The word select bit is generated from the address decoder. And one word at a time is selected for reading or writing. The design of the memory core's layout is also discussed since it should be optimized to save area and also should be convenient for realization. It's a full-custom layout. The address decoder is composed of combinational logic circuit and its layout is also designed as a full-custom layout. With all these modules, the integral structure of the SRAM is carried out.
