西方哲学从古希腊发展到现在,已经有2000多年的历史,巴门尼德作为古希腊重点代表人物之一,是学习和了解西方哲学无法绕开的人物,其思想对古希腊哲学家影响深远,被芝诺、柏拉图、亚里士多德等哲学家批判、继承和吸收,其在哲学上的成就或...西方哲学从古希腊发展到现在,已经有2000多年的历史,巴门尼德作为古希腊重点代表人物之一,是学习和了解西方哲学无法绕开的人物,其思想对古希腊哲学家影响深远,被芝诺、柏拉图、亚里士多德等哲学家批判、继承和吸收,其在哲学上的成就或许不如柏拉图和亚里士多德那样深刻,但是也有着不可忽视的作用。“esti”一词作为巴门尼德哲学中最重要的一个概念,标志着哲学从追寻具体的物质形态走向抽象思维,对于巴门尼德残篇2中“esti”一词的翻译,翻译家们众说纷纭,英译者将“esti”一词翻译为“is”,国内对于“esti”一词翻译为“是”还是“存在”产生了长久的讨论。本文主要就国内对“esti”一词不同的翻译进行解析和对比。Western philosophy has a history spanning over 2000 years since its origins in ancient Greece. Parmenides, as one of the most important figures of ancient Greece, is an essential figure in the study and understanding of Western philosophy. His ideas had a far-reaching impact on ancient Greek philosophers and were criticized, inherited and absorbed by philosophers such as Zeno, Plato, and Aristotle. While his philosophical contributions may not be as profound as those of Plato or Aristotle, they are nonetheless significant. The term “esti” is one of the most important concepts in Parmenides’ philosophy, marking the transition of philosophy from the pursuit of concrete material forms to abstract thinking. There has been much debate among scholars regarding the translation of “esti” in Fragment 2 of Parmenides. English translators generally render it as “is,” while in China, there has been a long-standing discussion on whether to translate it as “is” or “exist”. This paper primarily analyzes and compares the different translations of “esti” in China.展开更多
A novel rotational invariance technique for blind estimates of direction of arrival (I)OA) and Doppler frequency with unknown array manifold due to array sensor uncertainties is proposed, taking Doppler frequency diff...A novel rotational invariance technique for blind estimates of direction of arrival (I)OA) and Doppler frequency with unknown array manifold due to array sensor uncertainties is proposed, taking Doppler frequency difference between a successive pulses as rotational parameter. The effectiveness of the new method is confirmed by computer simulation. Compared with the existing 2-D DOA-frequeucy estimate techniques, the computation load of the proposed method can be saved greatly.展开更多
Dynamic time-varying operational conditions pose great challenge to the estimation of system remaining useful life （RUL） for the deteriorating systems. This paper presents a method based on probabilistic and stochas...Dynamic time-varying operational conditions pose great challenge to the estimation of system remaining useful life （RUL） for the deteriorating systems. This paper presents a method based on probabilistic and stochastic approaches to estimate system RUL for periodically moni- tored degradation processes with dynamic time-varying operational conditions and condition- specific failure zones. The method assumes that the degradation rate is influenced by specific oper- ational condition and moreover, the transition between different operational conditions plays the most important role in affecting the degradation process. These operational conditioqs are assumed to evolve as a discrete-time Markov chain （DTMC）. The failure thresholds are also determined by specific operational conditions and described as different failure zones. The 2008 PHM Conference Challenge Data is utilized to illustrate our method, which contains mass sensory signals related to the degradation process of a commercial turbofan engine. The RUE estimation method using the sensor measurements of a single sensor was first developed, and then multiple vital sensors were selected through a particular optimization procedure in order to increase the prediction accuracy. The effectiveness and advantages of the proposed method are presented in a comparison with exist- ing methods for the same dataset.展开更多
In this paper, we establish the maximum norm estimates of the solutions of the finite volume element method （FVE） based on the P1 conforming element for the non-selfadjoint and indefinite elliptic problems.
This paper studies the Galerkin finite element approximations of a class of stochas- tic fractionM differential equations. The discretization in space is done by a standard continuous finite element method and almost ...This paper studies the Galerkin finite element approximations of a class of stochas- tic fractionM differential equations. The discretization in space is done by a standard continuous finite element method and almost optimal order error estimates are obtained. The discretization in time is achieved via the piecewise constant, discontinuous Galerkin method and a Laplace transform convolution quadrature. We give strong convergence error estimates for both semidiscrete and fully discrete schemes. The proof is based on the error estimates for the corresponding deterministic problem. Finally, the numerical example is carried out to verify the theoretical results.展开更多
A carrier frequency offset （CFO） estimator was developed based on an interference cancellation scheme for an orthogonal frequency division multiplex access uplink. An initial CFO estimate was first ob- tained based ...A carrier frequency offset （CFO） estimator was developed based on an interference cancellation scheme for an orthogonal frequency division multiplex access uplink. An initial CFO estimate was first ob- tained based on the received training signals at each user＇s prescribed subcarder positions. Then, the re- ceived training signals were compensated by using the initial CFO estimates in the frequency domain and the multi-user interferences were estimated. Finally, the interference-cancelled training signals were used to reliably estimate each user＇s CFO. The CFO estimator performance was evaluated by the bit error rate per- formances of the CFO compensation-based receivers at the base station. Simulations show that with this optima CFO compensation receiver, the performance gain with the esti- mated CFO values is approximately 3 dB better at the 0.1% bit error rate than the initial CFO estimates.展开更多
This paper is concerned with a priori error estimates of a finite element method for numerical reconstruction of some unknown distributed flux in an inverse heat conduction problem. More precisely, some unknown distri...This paper is concerned with a priori error estimates of a finite element method for numerical reconstruction of some unknown distributed flux in an inverse heat conduction problem. More precisely, some unknown distributed Neumann data are to be recovered on the interior inaccessible boundary using Dirichlet measurement data on the outer ac- cessible boundary. The main contribution in this work is to establish the some a priori error estimates in terms of the mesh size in the domain and on the accessible/inaccessible boundaries, respectively, for both the temperature u and the adjoint state p under the lowest regularity assumption. It is revealed that the lower bounds of the convergence rates depend on the geometry of the domain. These a priori error estimates are of immense interest by themselves and pave the way for proving the convergence analysis of adaptive techniques applied to a general classes of inverse heat conduction problems. Numerical experiments are presented to verify our theoretical prediction.展开更多
精确无源移动目标定位是隧道、矿井巷道等复杂地下空间人员安全、灾后及时施救的关键技术之一。提出一种基于TOA/DOA参数估计的隧道高分辨率无源移动目标定位方法。鉴于隧道巷道内静物回波信号的多径较多且衰落严重,基于特征值分解的零...精确无源移动目标定位是隧道、矿井巷道等复杂地下空间人员安全、灾后及时施救的关键技术之一。提出一种基于TOA/DOA参数估计的隧道高分辨率无源移动目标定位方法。鉴于隧道巷道内静物回波信号的多径较多且衰落严重,基于特征值分解的零陷设计思路给出适合低信噪比条件下的最小范数强干扰抑制方法,抑制直达波和静物回波多径干扰信号,检测接收移动目标反射波;同时,为了克服隧道内的纳秒级密集多径和背景噪声,提出基于互高阶谱的RMCHS参数估计算法(Root Min-norm based on Cross High-order Specture,RMCHS),在低信噪比条件下进行高分辨率的TOA/DOA参数估计,从而实现基于TOA/DOA参数估计的隧道高分辨率无源移动目标定位。仿真实验表明,提出的强干扰抑制方法和RMCHS算法在隧道/巷道环境下有很强的鲁棒性,显著优于比较算法,减小了噪声和纳秒级密集多径对算法性能的影响。展开更多
文摘西方哲学从古希腊发展到现在,已经有2000多年的历史,巴门尼德作为古希腊重点代表人物之一,是学习和了解西方哲学无法绕开的人物,其思想对古希腊哲学家影响深远,被芝诺、柏拉图、亚里士多德等哲学家批判、继承和吸收,其在哲学上的成就或许不如柏拉图和亚里士多德那样深刻,但是也有着不可忽视的作用。“esti”一词作为巴门尼德哲学中最重要的一个概念,标志着哲学从追寻具体的物质形态走向抽象思维,对于巴门尼德残篇2中“esti”一词的翻译,翻译家们众说纷纭,英译者将“esti”一词翻译为“is”,国内对于“esti”一词翻译为“是”还是“存在”产生了长久的讨论。本文主要就国内对“esti”一词不同的翻译进行解析和对比。Western philosophy has a history spanning over 2000 years since its origins in ancient Greece. Parmenides, as one of the most important figures of ancient Greece, is an essential figure in the study and understanding of Western philosophy. His ideas had a far-reaching impact on ancient Greek philosophers and were criticized, inherited and absorbed by philosophers such as Zeno, Plato, and Aristotle. While his philosophical contributions may not be as profound as those of Plato or Aristotle, they are nonetheless significant. The term “esti” is one of the most important concepts in Parmenides’ philosophy, marking the transition of philosophy from the pursuit of concrete material forms to abstract thinking. There has been much debate among scholars regarding the translation of “esti” in Fragment 2 of Parmenides. English translators generally render it as “is,” while in China, there has been a long-standing discussion on whether to translate it as “is” or “exist”. This paper primarily analyzes and compares the different translations of “esti” in China.
基金Supported by the National Natural Science Foundation of China
文摘A novel rotational invariance technique for blind estimates of direction of arrival (I)OA) and Doppler frequency with unknown array manifold due to array sensor uncertainties is proposed, taking Doppler frequency difference between a successive pulses as rotational parameter. The effectiveness of the new method is confirmed by computer simulation. Compared with the existing 2-D DOA-frequeucy estimate techniques, the computation load of the proposed method can be saved greatly.
基金supported by the Fundamental Research Funds for the Central Universities(No.YWF-14-ZDHXY-16)
文摘Dynamic time-varying operational conditions pose great challenge to the estimation of system remaining useful life （RUL） for the deteriorating systems. This paper presents a method based on probabilistic and stochastic approaches to estimate system RUL for periodically moni- tored degradation processes with dynamic time-varying operational conditions and condition- specific failure zones. The method assumes that the degradation rate is influenced by specific oper- ational condition and moreover, the transition between different operational conditions plays the most important role in affecting the degradation process. These operational conditioqs are assumed to evolve as a discrete-time Markov chain （DTMC）. The failure thresholds are also determined by specific operational conditions and described as different failure zones. The 2008 PHM Conference Challenge Data is utilized to illustrate our method, which contains mass sensory signals related to the degradation process of a commercial turbofan engine. The RUE estimation method using the sensor measurements of a single sensor was first developed, and then multiple vital sensors were selected through a particular optimization procedure in order to increase the prediction accuracy. The effectiveness and advantages of the proposed method are presented in a comparison with exist- ing methods for the same dataset.
基金The Major State Basic Research Program (19871051) of China and the NNSP (19972039) of China.
文摘In this paper, we establish the maximum norm estimates of the solutions of the finite volume element method （FVE） based on the P1 conforming element for the non-selfadjoint and indefinite elliptic problems.
文摘This paper studies the Galerkin finite element approximations of a class of stochas- tic fractionM differential equations. The discretization in space is done by a standard continuous finite element method and almost optimal order error estimates are obtained. The discretization in time is achieved via the piecewise constant, discontinuous Galerkin method and a Laplace transform convolution quadrature. We give strong convergence error estimates for both semidiscrete and fully discrete schemes. The proof is based on the error estimates for the corresponding deterministic problem. Finally, the numerical example is carried out to verify the theoretical results.
基金Supported by the National Key Basic Research and Development (973) Program of China (No. 2007CB310601)
文摘A carrier frequency offset （CFO） estimator was developed based on an interference cancellation scheme for an orthogonal frequency division multiplex access uplink. An initial CFO estimate was first ob- tained based on the received training signals at each user＇s prescribed subcarder positions. Then, the re- ceived training signals were compensated by using the initial CFO estimates in the frequency domain and the multi-user interferences were estimated. Finally, the interference-cancelled training signals were used to reliably estimate each user＇s CFO. The CFO estimator performance was evaluated by the bit error rate per- formances of the CFO compensation-based receivers at the base station. Simulations show that with this optima CFO compensation receiver, the performance gain with the esti- mated CFO values is approximately 3 dB better at the 0.1% bit error rate than the initial CFO estimates.
文摘This paper is concerned with a priori error estimates of a finite element method for numerical reconstruction of some unknown distributed flux in an inverse heat conduction problem. More precisely, some unknown distributed Neumann data are to be recovered on the interior inaccessible boundary using Dirichlet measurement data on the outer ac- cessible boundary. The main contribution in this work is to establish the some a priori error estimates in terms of the mesh size in the domain and on the accessible/inaccessible boundaries, respectively, for both the temperature u and the adjoint state p under the lowest regularity assumption. It is revealed that the lower bounds of the convergence rates depend on the geometry of the domain. These a priori error estimates are of immense interest by themselves and pave the way for proving the convergence analysis of adaptive techniques applied to a general classes of inverse heat conduction problems. Numerical experiments are presented to verify our theoretical prediction.
文摘精确无源移动目标定位是隧道、矿井巷道等复杂地下空间人员安全、灾后及时施救的关键技术之一。提出一种基于TOA/DOA参数估计的隧道高分辨率无源移动目标定位方法。鉴于隧道巷道内静物回波信号的多径较多且衰落严重,基于特征值分解的零陷设计思路给出适合低信噪比条件下的最小范数强干扰抑制方法,抑制直达波和静物回波多径干扰信号,检测接收移动目标反射波;同时,为了克服隧道内的纳秒级密集多径和背景噪声,提出基于互高阶谱的RMCHS参数估计算法(Root Min-norm based on Cross High-order Specture,RMCHS),在低信噪比条件下进行高分辨率的TOA/DOA参数估计,从而实现基于TOA/DOA参数估计的隧道高分辨率无源移动目标定位。仿真实验表明,提出的强干扰抑制方法和RMCHS算法在隧道/巷道环境下有很强的鲁棒性,显著优于比较算法,减小了噪声和纳秒级密集多径对算法性能的影响。
