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211.
Case-cohort design usually requires the disease rate to be low in large cohort study,although it has been extensively used in practice.However,the disease with high rate is frequently observed in many clinical studies.Under such circumstances,it is desirable to consider a generalized case-cohort design,where only a fraction of cases are sampled.In this article,we propose the inference procedure for the additive hazards regression under the generalized case-cohort sampling.Asymptotic properties of the proposed estimators for the regression coefcients are established.To demonstrate the efectiveness of the generalized case-cohort sampling,we compare it with simple random sampling in terms of asymptotic relative efciency.Furthermore,we derive the optimal allocation of the subsamples for the proposed design.The fnite sample performance of the proposed method is evaluated through simulation studies. 相似文献
212.
In this note, we discuss a class of so-called generalized sampling functions. These functions are defined to be the inverse Fourier transform of a family of piecewise constant functions that are either square integrable or Lebegue integrable on the real number line. They are in fact the generalization of the classic sinc function. Two approaches of constructing the generalized sampling functions are reviewed. Their properties such as cardinality, orthogonality, and decaying properties are discussed. The interactions of those functions and Hilbert transformer are also discussed. 相似文献
213.
Consensus of heterogeneous multi-agent systems based on sampled data with a small sampling delay
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In this paper, consensus problems of heterogeneous multi-agent systems based on sampled data with a small sampling delay are considered. First, a consensus protocol based on sampled data with a small sampling delay for heterogeneous multi-agent systems is proposed. Then, the algebra graph theory, the matrix method, the stability theory of linear systems, and some other techniques are employed to derive the necessary and sufficient conditions guaranteeing heterogeneous multi-agent systems to asymptotically achieve the stationary consensus. Finally, simulations are performed to demonstrate the correctness of the theoretical results. 相似文献
214.
Epidemiologic studies use outcome-dependent sampling (ODS) schemes where, in addition to a simple random sample, there are also a number of supplement samples that are collected based on outcome variable. ODS scheme is a cost-effective way to improve study efficiency. We develop a maximum semiparametric empirical likelihood estimation (MSELE) for data from a two-stage ODS scheme under the assumption that given covariate, the outcome follows a general linear model. The information of both validation samples and nonvalidation samples are used. What is more, we prove the asymptotic properties of the proposed MSELE. 相似文献
215.
A high channel-count comb filter based on multi-concatenated sampled chirped fiber Bragg gratings(MC-SCFBGs) is proposed and optimally designed by using several chirped gratings with different fundamental grating periods,instead of non-grating sections of SCFBGs.The numerical simulations of the reflection spectra show that the channel spacing and the channel bandwidth in MC-SCFBGs are smaller than those in multi-concatenated chirped fiber Bragg gratings(MC-CFBGs) and that the spectral bandwidth of MC-SCFBGs can be greatly broadened by increasing the cascade number of the grating sections in each sampling period. 相似文献
216.
将PdCl2与ZIF-8的反应原料ZnO和2-甲基咪唑按照一定的比例,采用机械化学法原位将Pd2+负载在ZIF-8上(Pd2+/ZIF-8)。然后用NaBH4将Pd2+/ZIF-8进行还原,得到均匀分散的Pd纳米颗粒(Pd/ZIF-8)。通过XRD、N2吸附、透射电镜、ICP-AES、XPS等对Pd/ZIF-8的结构、形貌、价态等进行了表征。结果表明用机械化学法原位制备的Pd/ZIF-8具有分散均匀、容易大量制备的优点。该催化剂不仅能高效催化Suzuki-Miyaura交叉偶联反应,并且能够多次循环利用。 相似文献
217.
利用Gauss消元法原理,提出了线性DEDS研究中方程求解、传递矩阵求取、矩阵伪逆运算的机械化方法,为DEDS的建模、分析、计算提供了新的途径. 相似文献
218.
219.
提出了一种适用于DPSK调制的盲均衡算法。通过对接收信号的过采样,使原单信道等价为多信道。通过对信迫的辩识,采用简单决策反馈均衡器(DFE)实现信道的盲均衡。模拟结果显示,该方法具有较好的均衡效果。 相似文献
220.