面向ARM平台的音视频编码优化研究

ARM是性价比很高的嵌入式内核,非常适合作音视频编码系统的CPU。ARM硬件上支持复杂的DSP操作,通常可以在一个时钟周期内完成,极大地提高了音频编码程序的运行速度。在视频编码的数据处理指令中,使用捅形移位器进行移位预处理可以增加代码密度,从而减少取指令次数;而充分利用ARM的16个通用寄存器进行数据操作,也可以减少内存存取操作。实验证明,ARM可以有效提高音视频编码的运行性能。     

Implicit relation-aware social recommendation with variational auto-encoder

World Wide Web - Integrating social networks as auxiliary information shows effectiveness in improving the performance for a recommendation task. Typical models usually characterize the user trust...     

输气管线直埋全焊接球阀的结构特点及应用

阐述了适用于天然气高压管道的直埋全焊接球阀的结构特点，安装及日常运行维护的方法。     

可重配置无线网络中联合无线资源管理研究

对可重配置网络进行资源管理的研究是当前无线领域内的一个热点问题,而其中联合无线资源管理机制和算法是影响网络协同性能的最关键因素之一.本文介绍了可重配置系统的联合无线资源管理研究领域的最新成果和进展,并对研究热点和未来发展方向进行了分析展望.     

Document image retrieval based on multi-density features

The development of document image databases is becoming a challenge for document image retrieval techniques. Traditional layout-reconstructed-based methods rely on high quality document images as well as an optical character recognition (OCR) precision, and can only deal with several widely used languages. The complexity of document layouts greatly hinders layout analysis-based approaches. This paper describes a multi-density feature based algorithm for binary document images, which is independent of OCR or layout analyses. The text area was extracted after preprocessing such as skew correction and marginal noise removal. Then the aspect ratio and multi-density features were extracted from the text area to select the best candidates from the document image database. Experimental results show that this approach is simple with loss rates less than 3% and can efficiently analyze images with different resolutions and different input systems. The system is also robust to noise due to its notes and complex layouts, etc. Translated from Journal of Tsinghua University (Science and Technology), 2006, 46(7): 1 231–1 234 [译自: 清华大学学报 (自然科学版)]     

铌酸钾钠基透明上转换陶瓷材料制备及性能

采用热压烧结工艺, 以LiBiO₃作为烧结助剂, 制备了铌酸钾钠基透明上转换陶瓷K_0.5(1-y)Na_0.5(1-y)Li_yNb_1-yBi_yO₃- Er_0.005Yb_0.005x(Er³⁺/Yb³⁺:KNNLB, x=0~3, y=0~0.09)。并对其微观结构、光学透光率和上转换效应等进行了研究。结果表明该透明陶瓷具有正交钙钛矿型结构, 晶粒尺寸约0.5 μm, 致密度较高。该材料在红外区和可见光区有良好的透明性, 但是随着铒镱掺杂量的增加, 可见光区透光率呈明显的下降趋势。当y=0.06、x=0时, 在可见光范围内透过率可达到45%(样品厚度为0.5 mm), 红外光区域透过率达到95%以上。铒镱共掺杂透明陶瓷实现了在波长900 nm氙灯光源激发下的上转换效应。     

In situ formed two-phase metallic glass with surface fractal microstructure

The alloy La_27.5Zr_27.5Al₂₅Cu₁₀Ni₁₀ was found to phase separate during quenching from the melt into (La–Cu)-rich and (Zr–Ni)-rich glassy phases with compositions close to those of Zr–Ni–Al and La–Cu–Al bulk metallic glasses. As-quenched samples consist of two amorphous phases in spherical shape with a wide range of length scales from tens of micrometers to a few nanometers. Several self-similar generations of spheres in spheres were observed using scanning electron microscopy and transmission electron microscopy. Small angle X-ray scattering results show an exponential dependence to the power of −3.4 of the intensity on the scattering vector, indicating a surface fractal microstructure of dimension 2.6. The selected area diffraction patterns obtained from two-phase regions show two clearly distinguishable halo rings and the high resolution electron microscope image shows isotropic maze patterns with two different length scales corresponding to the difference in the average atomic distance of the two amorphous phases.     

自组织特征映射网络在建筑工程分类中的应用

针对传统建筑工程造价估算方法耗时量大、计算繁琐、误差频出的问题,提出了一种用自组织特征映射(SOFM)网络对建筑工程量样本量化后的值进行聚类的方法。该方法不需要手动标识训练数据集就可以实现不同类型的建筑样本自动分类,有助于提高传统建筑工程造价估算的效率。最后,通过实例验证了该方法的实用性和有效性。实验结果表明,改进的方法用于建筑工程造价估算较传统方法而言具有更高的准确率和更低的误报率。     

Existing forms of REE in gold-bearing pyrite of the Jinshan gold deposit,Jiangxi Province,China

Rare earth element(REE) is widely used in various fields of geology.Study of the existing forms of REE in geological objects is a necessity for us to solve geological problems related with REE.This paper tried to make it clear the existing forms of REE in gold-bearing pyrite in Jinshan gold deposit by stepwise dissolution test with ICP-MS analysis.Results showed that content of REE in fluid-inclusions of gold-bearing pyrite was very low,which only took about 0.07%-0.70% of the ΣREE,and that of pyrite phase ...     

Effect of Nb addition on the subsurface deformation behavior in Cu47Ti34Zr11Ni8 bulk metallic glasses through Vickers indentation

In this paper, 3 mm diameter (Cu₄₇Ti₃₄Zr₁₁Ni₈)_100−xNb_x (x = 0,1,2) glass forming alloys were fabricated by water-cooled copper mould cast. Microstructural characterization reveals that the monolithic Cu₄₇Ti₃₄Zr₁₁Ni₈ bulk metallic glass exhibits homogenous amorphous structure. While the alloys with Nb addition exhibit a composite structure. For alloys with x = 1, micro-scaled crystalline particles were found to distribute in the glassy matrix. For alloys with x = 2, the microstructure is dominated by a high density of dendritic phase embedded in the glassy matrix. Bonded interface technique was adopted to study the deformation behavior of the alloys underneath the Vickers indentation. It reveals that the subsurface shear patterns are significantly affected by the precipitated phases. The different deformation mechanism of the alloys resulted from the minor Nb addition was put forward and discussed.