Codebook design for uplink of densely small cells

The shrinking of cell-size brings significant changes to the wireless uplink of densely small cells （DSCs）. A codebook design is proposed that utilizes the strong line of sight （LOS） chan- nel component existing in a DSC system for uplink of the DSC system. To further improve the uplink performance, the high-rank codebook is designed based on singular value decomposition （SVD） due to the unnecessary preservation of strict constant modulus in the DSC system. And according to the simulation result, the proposed codebook leads to significant sum-rate gain and appreciable block error rate （BLER） performance improvement in the DSC system.     

Further results on limitations of sampled-data feedback

To control continuous-time uncertain dynamical systems with sampled data-feedback is prevalent today,but the sampling rate is usually not allowed to be arbitrarily fast due to various physical and/or computational constrains.In this paper,the authors examine the limitations of sampled-data feedback control for a class of uncertain systems in continuous-time,with sampling rate not necessary fast enough and with the unknown system structure confined to a set of functions with both linear and nonlinear growth.The limitations of the sampled-data feedback control for the uncertain systems are established quantitatively,which extends the existing related results in the literature.     

Backstepping approach to the adaptive regulator design for a one-dimensional wave equation with general input harmonic disturbance

This paper considers the parameter estimation and stabilization of an unstable one-dimensional wave equation with matched general harmonic disturbance at the controlled end. The backstepping method for infinite-dimensional system is adopted in the design of the adaptive regulator. It is shown that the resulting closed-loop system is asymptotically stable. Meanwhile, the estimated parameter is shown to be convergent to the unknown parameter as time goes to infinity.     

Risk reduction in a project portfolio

The positive impacts of managing projects as a portfolio are quantified by comparing the value of the integrated risk of a project portfolio and the aggregation of single project risks implemented separately. Firstly, the integrated risk is defined by proposing risky events based on set theory. Secondly, as projects interact with each other in a project portfolio, the integrated risk is evaluated by using a Bayesian network structure learning algorithm to construct an interdependent network of risks. Finally, the integrated risk of a practical case is assessed using this method, and the results show that the proposed method is an effective tool for calculating the extent of risk reduction of implementing a project portfolio and identifying the most risky project, so as to assist companies in making comprehensive decisions in the phase of portfolio selection and portfolio controlling.     

Simulation research on scattering characteristics by complex targets

A simulation approach based on a full-wave numerical method is presented to study electromagnetic characteristics by complex targets. How to validate simulation results is considered thoroughly under no analytical and measured data, where a double-check criterion is designed for our simulation approach. As an example, the scattering of F-117A is studied by using our simulation approach under all polarizations, different frequency bands, incident and scattering directions, etc., some of which, such as cross-polarization, bistatic RCS, have not been considered in the previous literature.     

玻璃纤维改性相变沥青混合料路用性能

为研究玻璃纤维对聚乙二醇(PEG)沥青混合料性能的增强效果,探究玻璃纤维掺量对其性能的影响规律,通过车辙试验、半圆弯拉试验、冻融劈裂试验研究了玻璃纤维PEG沥青混合料的高温稳定性、低温抗裂性和水稳定性,并利用室外调温试验研究掺加玻璃纤维前后PEG在沥青混合料中的降温效果.结果表明:玻璃纤维掺量为0.2％时,PEG沥青混...     

生物炭改性填埋场覆盖粉土的甲烷氧化能力试验研究

试验采用一种填埋场覆盖粉土作为土料,分别以木屑和水稻秸秆为原料热解的生物炭作为土料的改良剂,通过30天的甲烷氧化培养瓶试验研究了粉土以及两种不同生物炭改性土的甲烷氧化能力,同时研究了土样含水率对其甲烷氧化能力的影响。试验结果表明：两种生物炭均能提高粉土的甲烷氧化能力2.5倍左右。试验中所有土样在含水率在10%时几乎没有甲烷氧化能力,粉土以及两种生物炭改性土的甲烷氧化适宜含水率范围也各不相同,掺入生物炭能够增大粉土的甲烷氧化适宜含水率范围;本文运用击实曲线估计了试验中土样的水气双开敞(即水气都连通)条件的含水率范围,其结果表明：土样的水气双开敞条件含水率界限差值越大,土样的甲烷氧化适宜含水率界限差值也越大。掺入生物炭增大了粉土土样的水气双开敞条件的含水率范围,因此增大了其甲烷氧化适宜含水率范围。     

专业术语新词自动发现技术

从特定领域的科技文献中发现新词,不断地丰富词表,以保证词表的容量是信息检索的一个很重要的基础工作.介绍了专业术语新词自动发现技术中术语提取及词表丰富工作中采取的关键步骤：英文标题串的规范化、标题串中专业术语新词的提取、确定新词对应的概念.最后,文中对实验结果进行了统计和比较,解释了统计结果中出现的一些现象,并得出了结论.     

基于恒温晶体实现对纳秒级时间间隔的精确测量

采用恒温晶体震荡器作为时基,用高速分频器和单片机CTC组成计数器,实现对短时间瞬态变化,如瞬爆过程、保险丝熔断等微秒级乃至纳秒级过程进行精确,稳定的测量.     

A recording phase lag between ocean and continent climate changes: Constrained by the Matuyama/Brunhes polarity boundary

The Matuyama/Brunhes polarity boundary (MBPB) is recorded in Chinese loess L8, which is associated with the glacial period. It is proved that loess L8 is capable of recording earth’s secular variation, and the lock-in depth in Chinese loess is no more than that of marine sediments. Comparison with the location of MBPB in Chinese loess and marine sediments, it is put forward that there is a recording phase lag between ocean and continent climate changes.