Fault handling in large water networks with online dictionary learning

Fault detection and isolation in water distribution networks is an active topic due to the nonlinearities of flow propagation and recent increases in data availability due to sensor deployment. Here, we propose an efficient two-step data driven alternative: first, we perform sensor placement taking the network topology into account; second, we use incoming sensor data to build a network model through online dictionary learning. Online learning is fast and allows tackling large networks as it processes small batches of signals at a time. This brings the benefit of continuous integration of new data into the existing network model, either in the beginning for training or in production when new data samples are gathered. The proposed algorithms show good performance in our simulations on both small and large-scale networks.     

Excited-state absorption of meso-tetrasulfonatophenyl porphyrin: Effects of pH and micelles

The influence of the environment on the excited state transitions of meso-tetrakis(p-sulfonatophenyl) porphyrin (TPPS) is reported. TPPS was investigated in protonated and non-protonated forms, and in the presence of the cationic cetyltrimethylammonium bromide (CTAB) micelles. The singlet excited-state absorption spectra were measured by using the white-light continuum Z-scan technique and the triplet–triplet absorption spectra were acquired employing an association of laser flash photolysis and Z-scan techniques. Our results show that the perseveration of the molecular symmetry, upon excitation, depends on the state of multiplicity of the molecules, as well as on the environment and structural characteristics of the porphyrin. Additionally, it was observed that for excited molecules, the ring distortion caused by the protonation of porphyrin ring has great influence on the changes observed for the symmetry and vibronic structure. The results clearly show that the porphyrin investigated is a promising candidate for optical limiting applications for all investigated environments.     

Structure and electrical properties of Ca2+-doped (Na0.47Bi0.47Ba0.06)TiO3 lead-free piezoelectric ceramics

The lead-free piezoelectric ceramics (Na_.47Bi_.47Ba_.06)_1-xCa_xTiO₃ (x?=?0, 0.01, 0.02, 0.03, 0.05, and 0.08, abbreviated as BNBTC/0, BNBTC/1, BNBTC/2, BNBTC/3, BNBTC/5, and BNBTC/8, respectively) were obtained using the solid-state reaction method. The structure, electric conductivity, and dielectric, ferroelectric, and piezoelectric properties of the Ca²⁺-doped (Na_.47Bi_.47Ba_.06)TiO₃ ceramics were thoroughly investigated. The ceramics sintered at 1200?°C exhibit dense microstructures, having relative densities higher than 96%. The X-ray diffraction results demonstrate that all ceramics have a pure perovskite structure. The mean grain sizes of the ceramics are related to the Ca²⁺ quantity. A small quantity of Ca²⁺ ions (x?≤?0.03) improves the piezoelectric and ferroelectric properties of the samples. The dielectric behavior of the samples is sensitive to the Ca²⁺ content and electric poling. The results demonstrate that the electrical properties of the (Na_.47Bi_.47Ba_.06)TiO₃ lead-free ceramics can be well tuned by varying the Ca²⁺ quantity.     

Silver nanocluster formation in silicate glass by single step ion-exchange

We report the formation of silver nanoclusters of average size ∼ 1.1 nm in a single step ion-exchanged silica glass. Silver clusters are formed in a glass during ion-exchange by fine-tuning the ion-exchange parameters such as salt composition, temperature and time. Such nanocluster formation during ion-exchange preserves the waveguiding properties of the ion-exchanged surface of the glass making them suitable for nonlinear waveguide device fabrication.     

Application of an electronic nose for quality assessment of modified atmosphere packaged poultry meat

The applicability of an electronic nose for the quality control of modified atmosphere (MA) packaged broiler chicken cuts was evaluated in different temperature regimes. The electronic nose results were compared with those obtained by microbiological, sensory and headspace GC analyses. The electronic nose could clearly distinguish broiler chicken packages with deteriorated quality from fresh packages either earlier than or at the same time as the sensory quality deteriorated. Concerning the microbiological quality, the counts of Enterobacteriaceae and hydrogen sulphide-producing bacteria were most consistent with the electronic nose results. The results indicated that the electronic nose was capable of detecting even early signals of spoilage in MA packed poultry meat.     

Antibacterial effect of phenolic compounds from different wines

The antimicrobial properties of pure phenolic compounds and polyphenols of different wines against pathogens were investigated. It was observed that bacterial species exhibited different sensitivities towards the different concentrations of phenolic compounds. Escherichia coli was the most sensitive bacterium and Flavobacterium sp. was resistant against all phenolic compounds tested. All wine samples showed antimicrobial properties and the inhibition increased when the polyphenols concentration of wines increased. Clarified wines were inactive against all bacteria, indicating that polyphenolic compounds present in red wines, are responsible for the antimicrobial effects observed. The different concentrations of polyphenols in wines could have an important impact on consumers with the consequent increase in wine commercialization.     

MPEG-2／4AAC音频编码模块的验证

先进音频编码（AdvancedAudioCoding,AAC）以其多声道、多采样率、高压缩比、音质好等特点被广泛使用。文中首先介绍了MPEG-2／4AAC音频编码技术;接着基于MPEG-2／4AAC音频编码原理,开发了时钟复位、寄存器配置和音频数据收发的BFM模型,搭建了音频编码模块的RTL级虚拟验证平台,同时归纳了验证项;最后基于此验证平台和验证项,对设计进行了全面的仿真验证。实践证明该验证方法效率高、收敛快、覆盖率高,取得了较好的效果,为后续的FPGA平台验证和芯片应用提供了有力的保证。     

基于SoPC的智能监控卡设计与实现

针对机载机电管理计算机传统监控板卡智能化不高、集成度低的缺点,介绍了一种基于s0PC（SystemonProgram-mableChip）方案实现的智能监控卡。该卡使用FPGA内嵌的PPC处理器管理本地各种资源,主机通过PCI接口完成与PPC处理器的指令及数据交互。在FPGA片内集成了多个成熟IP产品,提高了系统集成度,缩短了产品开发周期。着重阐述了FPGA核心电路的系统架构设计、各功能模块的逻辑设计与实现、软硬件协同验证等。实际的系统测试表明该产品具有功能丰富、集成度高、扩展性强的特点。     

Bio-inspired self-organized cooperative control consensus for crowded UUV swarm based on adaptive dynamic interaction topology

Applied Intelligence - Cooperative control is currently a challenging topic of crowded unmanned underwater vehicle (UUV) swarm. However, individual behavior conflict and chain-avalanche collision...     

基于时变自回归模型的非平稳数据预测方法研究

针对现有的自回归（Autoregressive,AR）模型对非平稳数据预测效果不佳的问题,提出了基于时变自回归（Time-Varying Autoregressive,TVAR）模型的时序预测方法.针对某型国产飞机发动机的低压转速信号,使用TVAR模型分别进行点预测和区间预测,并与AR模型的点预测结果进行对比.研究结果表明,TVAR模型能够很好地反映非平稳数据的变化趋势.在给定置信水平下,TVAR预测区间能够包含真实数据,因此TVAR模型在时序预测中具有更好的预测效果.