基于压缩感知的水下图像去噪

水下环境复杂,水下摄像得到的图像较为模糊。采集数据时会采集到大量不包含任何有用信息的数据,噪声影响更严重。压缩感知理论提出,能用较低采样率高概率重构信号。为研究压缩感知对水下图像噪声的抑制作用,采用OMP,SP,COSAMP不同贪婪重构算法对水下图像进行不同采样率重构分析。实验结果表明,选取合适采样率既可以以少量数据重构图像,又可以抑制水下噪声,且OMP算法效果最好。     

Local adaptive shrinkage threshold denoising using curvelet coefficients

A new local adaptive shrinkage denoising approach based on neighbourhood windows and the scale of curvelet coefficients is presented. Mean filtering and median filtering according to the local characteristic of curvelet coefficients and noise level define the threshold function. Experimental results show that the proposed method outperforms the exiting curvelet shrinkage threshold method.     

Measurement of second-order nonlinear optical susceptibility of cBN crystal synthesized at high pressure and high temperature

We demonstrate a transverse electro-optical modulator based on a tiny and irregular octahedral wafer of cubic boron nitride (cBN) crystal that is prepared by hexagonal boron nitride at high pressure and high temperature using nitride as the catalyst. A continuous wave semiconductor laser at the wavelength of 650 nm is used as a light source. A novel electrode fabrication is designed, a developed method different from the conventional transverse electro-optical modulator is introduced and the expression of the intensity of output beam is thought over. We obtain the half-wave voltage based on experiments of transverse electro-optical modulation. The second-order nonlinear optical susceptibility χ_ijk⁽²⁾(ω,0)=1.919×10⁻¹² m/V of cBN crystal is calculated by means of the half-wave voltage.     

Efficient Pattern Generation for Small-Delay Defects Using Selection of Critical Faults

Testing for small-delay defects (SDDs) has become necessary as technology further scales. Existing tools and methodologies for generating SDD patterns suffer from: limited long-paths sensitization capability, overwhelming pattern volume, time-consuming pattern generation process, and vague evaluations of pattern quality. Such situation places patterns in a dilemma where the generation and application effort are huge yet the results cannot reflect the physical phenomena clearly enough for correct binning and diagnosis. In this paper, we focus on establishing a pattern generation flow that produces patterns of high application value. Firstly, critical faults are identified in order to generate high-quality original pattern repository with n-detect ATPG.A novelpattern evaluation and selection method that further minimizes pattern count while maintaining the SDD detection ability is then presented. Top-off ATPG is then performed to ensure meeting the target fault coverage. Along with the flow, multiple evaluation metrics are also proposed to measure the pattern’s efficiency on SDD coverage, unique SDD detection, detectable SDD size, long path distribution, etc. Experimental results demonstrate that the proposed critical fault-based method improves long path sensitization efficiency by 2.5× without impairing its average delay and saves approximately 80 % CPU runtime compared with total fault-based method. Comparing with timing-aware ATPG, the generated pattern set detects equivalent or even more SDDs with significantly reduced pattern count.     

Joint multi-radio multi-channel assignment, scheduling, and routing in wireless mesh networks

The IEEE 802.11 DCF and EDCA mechanisms based on CSMA/CA are the most widely used random channel access mechanisms in wireless mesh networks (WMNs), but unfortunately these cannot effectively eliminate hidden terminal and exposed terminal problems in multi-hop scenarios. In this paper, we propose a set of efficient multi-radio multi-channel (MRMC) assignment, scheduling and routing protocols based on Latin squares for WMNs with MRMC communication capabilities, called “M4”, i.e., the Multiple access scheduling in Multi-radio Multi-channel Mesh networking. M4 uses nodal interference information to form cliques for inter-cluster and intra-cluster inWMNs, and then applies Latin squares to map the clique-based clustering structure to radios and channels for communication purposes. Then, M4 again applies Latin squares to schedule the channel access among nodes within each cluster in a collision-free manner. From a systematic view, we also design the corresponding MRMC routing to support M4 communication. Extensive simulation results show that M4 achieves much better performance than IEEE 802.11 standards and other channel access control protocols.     

无线POS行业应用在EGPRS网络中的解决方案

重点讨论运营商在维护集团客户的GPRS无线POS业务中发现的问题,并给出相关改进建议,以及升级至EGPRS网络后需要考虑的问题。     

阻焊塞孔工艺改善

通过改良阻焊塞孔工具、规范网印塞孔操作、修改后固化参数,改善公司阻焊塞孔质量不稳定的问题。     

分子氧氧化环己烷制环己酮催化剂的研究进展

综述了分子氧氧化环己烷制备环己酮催化剂的最新进展,重点介绍了在仿生催化剂、光催化剂和分子筛催化剂3方面的研究成果,指出负载型的金属卟啉催化剂有望在工业上得到应用。     

计算机与GPS-OEM板之间的通讯研究

以MOTOROLA公司生产的GT接收机为例，着重研究了计算机与GPS－OEM板之间的串行通讯，为GPS接收机的具体开发应用打下基础。     

Environmental controls of cadmium desorption during CO₂ leakage

Geologic carbon sequestration represents a promising option for carbon mitigation. Injected CO(2), however, can potentially leak into water systems, increase water acidity, and mobilize metals. This study used column experiments to quantify the effects of environmental controls on cadmium desorption during CO(2) leakage in subsurface systems without ambient flow. Results show that fast leakage rates are responsible for earlier and larger amounts of Cd desorption. Long weathering time of Cd laden clay leads to low Cd desorption. Calcite content as low as 10% can mitigate the effect of pH reduction and result in zero Cd desorption. Increasing the salinity of the leaking fluid has a relatively minor effect, primarily due to the offsetting impacts of an increased extent of ion exchange and the decrease in CO(2) solubility (and therefore acidity). This work systematically quantifies, for the first time, the effects of environmental controls on Cd desorption and points to key parameters for risk assessment associated with metal mobilization during CO(2) leakage.