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排序方式: 共有56条查询结果,搜索用时 15 毫秒
1.
Hu Zhaoyang Suo Xufei Shen Yongxing Jiang Yu-Xi Cheng Jun-Bo 《International Journal of Fracture》2022,235(2):231-242
International Journal of Fracture - Adiabatic shear band (ASB) is one of the most important failure modes under high strain-rate deformation. In this work, we propose a hybrid damage model to... 相似文献
2.
Jin-Yuan Wang Jun-Bo Wang Ming Chen Jianxin Dai 《Wireless Personal Communications》2014,75(2):1099-1114
Recently, much attention has been drawn to distributed antenna systems (DAS), which are proposed to improve the performance of mobile communication systems. This paper focuses on the analysis of the average symbol error rate (SER) of DAS over a generic composite channel. Initially, a new composite channel model is considered for DAS, which is a mixture of path loss, lognormal shadowing and generalized-Gamma fast fading. This composite channel model is a generic model, which includes many well-known composite channel models as special cases. Based on the channel model, the cumulative distribution function of the output signal-to-noise ratio is obtained by employing selective transmission scheme. Moreover, by averaging the channel conditions and the positions of the MS in the cell, an approximate expression of the average SER is derived, which is a unified form of expression for many commonly used modulation schemes. Numerical results show that the derived expression of the average SER can provide sufficient precision for evaluating the SER performance of DAS under different modulation schemes. 相似文献
3.
目的建立一种普洱茶中茶多糖的提取工艺。方法以普洱茶为材料,采用水提醇沉法,研究了浸提温度、浸提时间、浸提次数、乙醇浓度4个因素对普洱茶中茶多糖提取率的影响,并通过正交实验确定茶多糖的最佳提取工艺。且用此提取工艺测定市售不同级别普洱茶中茶多糖含量。结果普洱茶中茶多糖的最佳提取工艺为:浸提温度90℃,浸提时间40 min,浸提次数3次,乙醇浓度80%。该提取工艺重复性好,吸光度与葡萄糖含量呈良好的线性关系(n=5),线性范围0.02~0.10 mg/L(r2=0.9999)。实验也发现,普洱茶的嫩度越低,茶多糖的含量越高。结论本方法简便、快捷、重复性好,可作为茶叶多糖原材料和产品质量控制的方法。 相似文献
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提出主元分析PCA(Principal Component Analysis)用于语音检测的方法研究.用主元分析法在多维空间中建立坐标轴,将待处理信号投影到该坐标轴中,通过分析投影结果判断是否为语音信号.通过将语音和非语音分别建立子空间,来区分语音和非语音信号.该方法不同于常规的语音时域、频域处理方法,而是在多维空间中对信号进行分析.实验结果表明,该方法准确率高、简单、容易实现,而且能区分多种非语音信号. 相似文献
6.
容错多处理机中一种高效的实时调度算法 总被引:5,自引:0,他引:5
针对基于主副版本容错的多处理机中独立的、抢占性的硬实时任务,提出了一种高效的调度算法——TPFTRM(task partition based fault tolerant rate-monotonic)算法.该算法将单机实时RM 算法扩展到容错多处理机上,并且调度过程中从不使用主动执行的任务副版本,而仅使用被动执行和主副重叠方式执行的任务副版本,从而最大限度地利用副版本重叠和分离技术提高了算法调度性能.此外,TPFTRM 根据任务负载不同将任务集合划分成两个不相交的子集进行分配;还根据处理机调度的任务版本不同,将处理机集合划分成3 个不相交的子集进行调度,从而使TPFTRM 调度算法便于理解、实现以及减少了调度所需要的运行时间.模拟实验对各种具有不同周期和任务负载的任务集合进行了调度测试.实验结果表明,TPFTRM与目前所知同类算法相比,在调度相同参数的任务集合时不仅明显减少了调度所需要的处理机数目,还减少了调度所需要的运行时间,从而证实了TPFTRM 算法的高效性. 相似文献
7.
The Multi-Carrier Code Division Multiple Access (MC-CDMA) is becoming a very attractive multiple access technique for high-rate data transmission in the future wireless communication systems. This paper is focused on the joint channel and power allocation in the downlink transmission of multi-user MC-CDMA systems and considers the throughput maximization problem as a mixed integer optimization problem. For simple analysis, the problem is divided into two less complex sub-problems: power allocation and channel allocation, which can be solved by a suboptimal Adaptive Power Allocation (APA) algorithm and an optimal Adaptive Channel Allocation (ACA) algorithm, respectively. By combining APA and ACA algorithms, an adaptive channel and power allocation scheme is proposed. The numerical results show that the proposed APA algorithm is more suitable for MC-CDMA systems than the conventional equal power allocation algorithm, and the proposed channel and power allocation scheme can significantly improve the system throughput performance. 相似文献
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9.
Byung-Tak Lee Min-Suk Kwon Jun-Bo Yoon Sang-Yung Shin 《Photonics Technology Letters, IEEE》2000,12(1):62-64
Polymeric large-core (47 μm×41 μm) optical waveguides for optical interconnects have been fabricated by using a rubber molding process. For low-cost low-loss large-core waveguides, our newly developed thick-photoresist patterning process is used for a master fabrication. Also a low-loss thermocurable polymer, perfluorocyclobutane (PFCB), is used in fabricating optical waveguides by rubber molding for the first time. The propagation loss is measured to be 0.4 dB/cm at the wavelength of 1.3 μm, and 0.7 dB/cm at the wavelength of 1.55 μm 相似文献
10.