Acoustic emission from gas-filled coal under triaxial compression

Acoustic emission (AE) experiments have been performed on gas-saturated coal specimens under conventional triaxial compression. The AE characteristics were investigated for a methane gas flow through the coal specimen. One AE parameter, AE count, when normalized by the total count number was used to represent the damage evolution in the gassy coal. It is shown that this AE parameter is a reasonable indicator for damage occurring within the coal specimen since its envelope has almost the same shape as the complete stress–strain curve, except for a short time delay. In addition, the change in AE count is highly consistent with the change in coal permeability. Test results also show that methane containing coal emits a small number of AE events before entering the yield stage. AE activity gradually increases during the yield process up to the peak stress. The lowest permeability corresponds to the highest AE activity, implying failure will soon occur. An AE based constitutive model was constructed and the theoretical results agree well with those of experiments.     

Effects of AMF on soil enzyme activity and carbon sequestration capacity in reclaimed mine soil

A series of pot experiments and field trials were carried out to evaluate the effects of arbuscular mycorrhizal fungi (AMF) on activities of soil enzymes and carbon sequestration capacity in reclaimed mine soil. A complex substrate of coal gangue, fly ash and sludge was used as reclaimed mine soil, and ryegrass was planted with AMF inoculation to construct a plant-complex substrate-microbe ecological restoration system. The changes to the soil organic carbon (SOC), activities of soil enzymes and glomalin-related soil protein (GRSP) were measured and the effects of AMF on activities of soil enzymes and carbon sequestration capacity in reclaimed mine soil were analyzed. The results show that the contents of GRSP (total glomalin (TG) and easily extractable glomalin (EEG)), SOC and activities of enzymes increased, and the increments were higher in the AMF inoculation treated plant-complex substrate-microbe ecological restoration systems than those with no AMF inoculated treatments after 12 months of ryegrass growth. TG, EEG and soil enzyme activity have a significant positive correlation, and the correlative coefficient was 0.427–0.573; SOC and TG, EEG have a significant positive correlation (p < 0.01), indicating that AMF plays an important role in carbon sequestration of reclaimed mine soils.     

Identification of nitrate sources in Taihu Lake and its major inflow rivers in China, using δ(15)N-NO(3)(-) and δ(18)O-NO(3)(-) values

In the present study, δ(15)N and δ(18)O-NO(3)(-) values, as well as concentrations of some major ion tracers were determined in seasonal water samples from Taihu Lake and major watersheds to investigate the temporal and spatial variations of nitrate sources and assess the underlying nitrogen (N) biogeochemistry process. The results lead to the conclusion that the nitrate concentrations in Taihu Lake are lower in summer than that in winter due to the dilution effect of wet deposition. In winter, sewage and manure were the primary nitrate sources in major inflow rivers and North Taihu Lake (NTL), while nitrate sources in East Taihu Lake (ETL) probably derived from soil organic N. In summer, atmospheric deposition and sewage/manure inputs appear to play an important role in controlling the distribution of nitrates in the whole lake. The δ(18)O-NO(3)(-) values suggest that the nitrate produced from microbial nitrification is another major nitrate source during both winter and summer months. The variations in isotopic values in nitrate suggest denitrification enriched the heavier isotopes of nitrate in NTL in winter and in ETL in summer.     

基于差分演化算法的软子空间聚类

软子空间聚类算法的性能主要取决于其目标函数和搜索策略.文中提出了一种基于差分演化算法的软子空间聚类算法DESC.首先,设计了一个结合模糊加权类内相似性和界约束权值矩阵的新目标函数.然后,提出了新的隶属度计算方法.最后,引入了一种有效的全局搜索算法——复合差分演化算法,并运用该算法优化新目标函数和搜索子空间中的聚类.实验表明,新目标函数和复合差分演化算法的引入有效地提高了软子空间聚类算法的性能,新算法较已有软子空间聚类算法有明显优势.     

缫丝排序算法

文中提出一种改进的排序算法,弥补了快速排序在大规模下堆栈低效及合并排序在小规模下优势不明显的问题.算法扩展了合并排序思想,从一种特殊的蚕茧缫丝工艺得到启发,使用2～6个滚轴分离待排序列中的有序片段,在滚轴始末端扩展新数据,从而达到在合并操作前增加有序子序列长度的目的.理论推导表明,缫丝排序中的基本操作数量较合并排序减少4.75N,相当于将待排序列缩小至原有规模的1/4;效率测试实验表明,缫丝排序在各种规模下均能获得相比最快经典排序算法10％～15％的稳定优势,相比前人的改进排序算法具备相当的互补性,并能有效降低排序库函数自适应选择算法的实现复杂度.     

基于嵌入式及ZigBee技术的居室环境监测系统

设计了一套智能家居环境监测系统。系统通过ZigBee终端节点采集居室传感器数据信息,在居室内部建立ZigBee无线网络,并将传感器信息由ZigBee协调器模块传给系统的嵌入式家庭网关,由家庭网关对所接收的数据协议处理后,进行数据融合和模糊处理,最后将其转化成日常生活语言式的直观信息,显示到QT界面系统中。该网关也可以通过无线网络给各个终端节点发送指令信息或Internet网络与外部进行信息的沟通。系统具有手持可移动的特点,不仅可以随意增减节点数,也可将采集节点随意放置,应用于超市或者其他环境中。     

基于非负矩阵分解的鲁棒哈希函数验证性研究

矩阵分解是实现大规模数据处理与分析的一种有效工具。矩阵的非负矩阵分解NMF(Non-Negative Matrix Factorization)变换是一种正交变换,是在矩阵中所有元素均为非负的条件下对其实现的非负分解。鲁棒哈希技术利用密钥提取多媒体内容的某些鲁棒特征,通过进一步压缩产生哈希值,通过比较跟随媒体内容传送来的哈希和接收端产生的哈希,实现对媒体内容的真实性认证。     

Aggregate keyword search on large relational databases

Keyword search has been recently extended to relational databases to retrieve information from text-rich attributes. However, all the existing methods focus on finding individual tuples matching a set of query keywords from one table or the join of multiple tables. In this paper, we motivate a novel problem of aggregate keyword search: finding minimal group-bys covering a set of query keywords well, which is useful in many applications. We develop two interesting approaches to tackle the problem. We further extend our methods to allow partial matches and matches using a keyword ontology. An extensive empirical evaluation using both real data sets and synthetic data sets is reported to verify the effectiveness of aggregate keyword search and the efficiency of our methods.     

基于MAX263的带通跟踪滤波设计

介绍了MAX263滤波芯片性能,分析了其软件设计方法及其工作原理,结合锁相环频率跟踪原理设计了针对转子不平衡量电信号的带通跟踪滤波器,实验证明该方法滤波效果十分明显,能够有效滤除干扰信号,且电路简单,具有很高的应用价值。     

Reshaping 3D facial scans for facial appearance modeling and 3D facial expression analysis

3D face scans have been widely used for face modeling and analysis. Due to the fact that face scans provide variable point clouds across frames, they may not capture complete facial data or miss point-to-point correspondences across various facial scans, thus causing difficulties to use such data for analysis. This paper presents an efficient approach to representing facial shapes from face scans through the reconstruction of face models based on regional information and a generic model. A new approach for 3D feature detection and a hybrid approach using two vertex mapping algorithms, displacement mapping and point-to-surface mapping, and a regional blending algorithm are proposed to reconstruct the facial surface detail. The resulting models can represent individual facial shapes consistently and adaptively, establishing facial point correspondences across individual models. The accuracy of the generated models is evaluated quantitatively. The applicability of the models is validated through the application of 3D facial expression recognition using the static 3DFE and dynamic 4DFE databases. A comparison with the state of the art has also been reported.