The cyclically symmetric anti-plane fracture analysis for the arc-shaped interface in a non-homogeneous bimaterial cylindrical structure

A hollow cylinder, which consists of an inner functionally graded elastic substrate and an outer functionally graded elastic layer with cyclically symmetric cracks (a special case of multiple cracks), is considered under anti-plane shear load. The method of variable separation is employed to reduce the mixed boundary value problems to a Cauchy singular integral equation, which is solved numerically by the Lobatto–Chebyshev quadrature technique. Numerical results are presented to show the effects of geometrical and physical quantities on the stress intensity factors (SIFs). Parametric studies are conducted on the SIFs, and practical guidelines are given for the optimization of the fracture performance: (a) the SIFs depend on the ratio between the outer and inner radii, and the ratio should be at least 1.1; (b) the outer elastic layer should be stiffer than the inner elastic substrate; (c) large non-homogeneity parameter of the outer graded layer and small non-homogeneity parameter of the inner graded substrate are beneficial to SIFs reduction; (d) there is a strong interference between the stress fields around multiple cracks when the cyclically symmetric parameter increases.     

Enriching Context Information for Entity Linking with Web Data

Journal of Computer Science and Technology - Entity linking (EL) is the task of determining the identity of textual entity mentions given a predefined knowledge base (KB). Plenty of existing...     

面向GPU平台的复杂网络core分解方法研究

在复杂网络理论中,core分解是一种最基本的度量网络节点“重要性”并分析核心子图的方法.Core分解广泛应用于社交网络的用户行为分析、复杂网络的可视化、大型软件的代码静态分析等应用.随着复杂网络的图数据规模和复杂性的增大,现有研究工作基于多核CPU环境设计core分解并行算法,由于CPU核数和内存带宽的局限性,已经无法满足大数据量的高性能计算需求,严重影响了复杂网络的分析应用.通用GPU提供了1万以上线程数的高并行计算能力和高于100GB/s访存带宽,已被广泛应用于大规模图数据的高效并行分析,如广度优先遍历和最短路径算法等.为了实现更为高效的core分解,提出面向GPU平台下的复杂网络core分解的两种并行策略.第1种RLCore策略基于图遍历思想,利用GPU高并发计算能力对网络图结构自底向上遍历,逐步迭代设置各节点所属的core层;第2种ESCore策略基于局部收敛思想,对各节点从邻居节点当前值进行汇聚计算更新直至收敛.ESCore相比RLCore能够大大降低遍历过程中GPU线程更新同一节点的同步操作开销,而其算法的迭代次数受收敛率的影响.在真实网络图数据上的实验结果表明,所提出的两个策略在效率和扩展性方面能够大幅优于现有其他方法,相比单线程上的算法高达33.6倍性能提升,且遍历边的吞吐性能(TEPS)达到406万条/s,单轮迭代的ESCore的执行效率高于RLCore.     

Multi-Sensor Estimation for Unreliable Wireless Networks with Contention-Based Protocols

The state estimation plays an irreplaceable role in many real applications since it lays the foundation for decision-making and control. This paper studies the multi-sensor estimation problem for a contention-based unreliable wireless network. At each time step, no more than one sensor can communicate with the base station due to the potential contention and collision. In addition, data packets may be lost during transmission since wireless channels are unreliable. A novel packet arrival model is proposed which simultaneously takes into account the above two issues. Two scenarios of wireless sensor networks (WSNs) are considered: the sensors transmit the raw measurements directly and the sensors send the local estimation instead. Based on the obtained packet arrival model, necessary and sufficient stability conditions of the estimation at the base station side are provided for both network scenarios. In particular, all offered stability conditions are expressed by simple inequalities in terms of the packet arrival rates and the spectral radius of the system matrix. Their relationships with existing related results are also discussed. Finally, the proposed results are demonstrated by simulation examples and an environment monitoring prototype system.     

Improving the Quality of Crowdsourced Image Labeling via Label Similarity

Crowdsourcing is an effective method to obtain large databases of manually-labeled images, which is especially important for image understanding with supervised machine learning algorithms. However, for several kinds of tasks regarding image labeling, e.g., dog breed recognition, it is hard to achieve high-quality results. Therefore, further optimizing crowdsourcing workflow mainly involves task allocation and result inference. For task allocation, we design a two-round crowdsourcing framework, which contains a smart decision mechanism based on information entropy to determine whether to perform the second round task allocation. Regarding result inference, after quantifying the similarity of all labels, two graphical models are proposed to describe the labeling process and corresponding inference algorithms are designed to further improve the result quality of image labeling. Extensive experiments on real-world tasks in Crowdflower and synthesis datasets were conducted. The experimental results demonstrate the superiority of these methods in comparison with state-of-the-art methods.     

航拍图像的无线传感网节点识别与定位算法

为提高节点定位精度并减少能量耗费,提出一种基于航拍图像处理的节点识别与定位算法.该算法主要思想是将基于深度学习模型的图像识别技术应用到节点识别与定位中.首先通过一个携带GPS的航拍器在节点部署区域自主采集节点图像,利用图像识别技术精确识别定位航拍器所拍摄节点,然后利用贝叶斯平均模型为已识别节点匹配节点编号.最后,将被定位节点升级为锚节点,结合经典定位算法确定未被拍摄的节点位置.通过大量的仿真证明了该算法的有效性.此外,利用25 Micaz节点和一个航拍器进行了实验,实验结果表明,该算法具有较好的鲁棒性、扩展性及定位精度,与传统定位算法相比定位精度提高约10%~30%.     

Value-added utilization of yak milk casein for the production of angiotensin-I-converting enzyme inhibitory peptides

Yak (Bos grunniens) milk casein derived from Qula, a kind of acid curd cheese from northwestern China, was hydrolysed with alcalase. The hydrolysates collected at different hydrolysis times (0 min, 60 min, 120 min, 180 min, 240 min, 300 min, 360 min) were assayed for the inhibitory activity of angiotensin-I-converting enzyme (ACE), and the one obtained at 240 min hydrolysis showed the highest ACE inhibitory activity. The active hydrolysate was further consecutively separated by ultrafiltration with 10 kDa and then with 6 kDa molecular weight cut-off membranes into different parts, and the 6 kDa permeate showed the highest ACE-inhibiting activity. This active fraction was further purified to yield two novel ACE-inhibiting peptides, whose amino acid sequences were Pro–Pro–Glu–Ile–Asn (PPEIN)(κ-CN; f156–160) and Pro–Leu–Pro–Leu–Leu (PLPLL) (β-CN; f136–140), respectively. The molecular weight and IC₅₀ value of the peptides were 550 Da and 566.4 Da, and 0.29 ± 0.01 mg/ml and 0.25 ± 0.01 mg/ml, respectively.     

常压干燥制备TiO2气凝胶及光催化降解含油污水性能研究

以钛酸四丁酯(TBT)为原料,利用溶胶–凝胶法、小孔干燥和老化液浸泡工艺在常压下制备出了完整、无开裂的TiO2气凝胶块体.研究了小孔干燥和老化液浸泡技术对常压制备TiO2气凝胶的影响,研究结果表明:小孔干燥能够降低TiO2醇凝胶干燥过程中所受的不均匀收缩应力,而TBT醇溶液和TEOS醇溶液浸泡处理,能够增强凝胶的骨架强度,有助于减轻凝胶在干燥过程中的收缩和开裂,制备出完整的高性能TiO2气凝胶块体.基于小孔干燥和TEOS乙醇溶液浸泡老化处理,制备得到的高性能完整TiO2气凝胶块体,其密度为0.184 g/cm3,比表面积达389.5 m2/g.用高温煅烧后的锐钛矿相TiO2气凝胶催化降解渤海原油污水模拟溶液,在TiO2气凝胶加入量为400 mg/L的情况下,90 min内对渤海原油污水的去除率最高可达91%.     

Determination of tertiary butylhydroquinone in edible vegetable oil by liquid chromatography/ion trap mass spectrometry

A simple, sensitive and accurate analytical method for quantification of tertiary butylhydroquinone (TBHQ) in edible vegetable oil was established by liquid chromatography/ion trap mass spectrometry (LC/ITMS). After extraction, 5 μl of the extracts was directly injected into LC/ITMS for TBHQ determination. Ethanol was selected as the extraction solvent. The optimized fragmentation amplitude was 1.70 V and electrospray ionization (ESI) was more suitable than atmospheric pressure chemical ionization (APCI) for TBHQ detection. The calibration curve showed good linearity (R² = 0.9990) and recoveries from spiked samples ranged from 81.9% to 110.5%. Relative standard deviations of intra-day and inter-day were in the ranges 2.5–5.7% and 3.9–13.8%, respectively. The procedure allows the detection of 0.3 mg/kg TBHQ in edible vegetable oil. Typical edible vegetable oils in the market were detected for TBHQ by the proposed method. As results, TBHQ was detected in blend oil, soybean salad oil and camellia oil samples.     

Corrosion Resistance of AZ91 Mg Alloy Modified by High-Current Pulsed Electron Beam

The high-current pulsed electron beam(HCPEB) treatment with current density 6 J/cm~2 was applied on AZ91 Mg alloy to improve its corrosion resistance. Results showed that the net-like Mg_(17)Al_(12) disappeared on the surface of AZ91 Mg alloy after irradiation by HCPEB, which was instead of supersaturated Al element on the surface. Nevertheless, the application of HCPEB also led to the formation of crater-like and groove-like structures as well as micro-cracks on the surface of AZ91 Mg alloy. After HCPEB treatment by 3, 5 and 10 pulses, the AZ91 Mg alloy exhibited better corrosion resistance.However, the increasing amount of micro-cracks reduced the anti-corrosive properties of AZ91 Mg alloy as the pulse increased to 20 and 30.