A nodal link perceptron network with applications to control of anonholonomic system

A new perceptron neural network (PNN) for functional approximation and control of a general class of nonlinear systems is introduced. The basic structure of the network along with the conditions for its exponential convergence under a suitable training law are derived. A novel discrete-time control strategy is formulated that employs the PNN for direct online estimation of the feedforward control input. The developed controller can be applied to both discrete- and continuous-time plants. Unlike most of the existing direct adaptive or learning schemes, the nonlinear plant is not assumed to be feedback linearizable. The developed controller is then applied for tracking control of a nonholonomic (free-flying) robot. The simulation results of this application demonstrate a perfect tracking performance after the network is fully trained.     

A novel chelate-assisted C−C bond formation on a Cd(II) complex of an asymmetric heptadentate(N7) tripodal Schiff base ligand

Cadmium(II) complexes of some potentially heptadentate tripodal Schiff base ligands with the general formula N{(CH₂)_nNCHC₅H₄N}₂{(CH₂)_mNCHC₅H₄N}) (where n = m = 2, L₂₂₂; n = 2, m = 3, L₃₂₂; n = 3, m = 2, L₃₃₂) have been studied. These ligands are products of the full condensation of a number of tripodal tetraamines with 2-pyridinecarboxaldehyde. An unusual reaction of an additional 2-pyridine-carboxaldehyde with a methylene group adjacent to the imine bond only during template preparation of [Cd(L₃₃₂)]²⁺ was observed. The latter reaction is a novel chelate-assisted C?C bond formation because it is occurred only where a rigid five-membered chelate ring is present.     

Dynamische Steifigkeit und Dämpfung von Pfahlgruppen

Dynamic stiffness and damping properties of pile groups. The dynamic stiffness and damping properties of pile‐groups have been investigated in this paper. Also, the substantial influence of these properties on an economic structure and foundation design is demonstrated. The analysis has been carried out using the “Thin‐Layer‐Method”, which is a very efficient and powerful analysis procedure in frequency domain.     

Concentrations of polychlorinated biphenyls in indoor air and polybrominated diphenyl ethers in indoor air and dust in Birmingham, United Kingdom: implications for human exposure

Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) were measured in air (using PUF disk passive samplers) in 31 homes, 33 offices, 25 cars, and 3 public microenvironments. Average concentrations of sigmaBDE (273 pg m(-3)) and sigmaPCB (8920 pg m(-3)) were an order of magnitude higher than those previously reported for outdoor air. Cars were the most contaminated microenvironment for sigmaBDE (average = 709 pg m(-3)), but the least for sigmaPCB (average = 1391 pg m(-3)). Comparison with data from a previous spatially consistent study, revealed no significant decline in concentrations of sigmaPCB in indoor air since 1997-98. Concentrations in indoor dust from 8 homes were on average 215.2 ng sigmaBDE g(-1), slightly higher than other European dust samples, but twenty times lower than Canadian samples. Inhalation makes an important contribution (between 4.2 and 63% for adults) to overall UK exposure to sigmaPCB. For sigmaBDE, dust ingestion makes a significant but--in contrast to Canada-a not overwhelming contribution (up to 37% for adults, and 69% for toddlers). Comparison of UK and Canadian estimates of absolute exposure to sigmaBDE suggest that differences in dust contamination are the likely cause of higher PBDE body burdens in North Americans compared to Europeans.     

利用不稳定压力数据建立碳酸盐岩储集层模型

地质模型通常是根据地质信息,利用地球物理和岩石物理资料来建立.为了建立准确的碳酸盐岩油藏(伊朗海上油田)模型,不仅利用了地震和测井数据,也结合了该油田现有99井次的试井数据.在试井解释过程中观察到了许多特征,如封闭断层、水层、裂缝和分层系统,其中某些特征只能利用压力瞬态数据来识别,如地震数据中观察不到的一条封闭断层在试井曲线上则可识别.除了识别构造特征外,试井解释得到的渗透率数据也可用于绘制渗透率等值线图,而不再采用岩心分析得到的渗透率数据.试井得到的渗透率是泄油区域的有效渗透率,而岩心分析得到的渗透率并不能代表非均质油藏的渗透性.利用非稳态压力分析结果建立油藏模型,可以提高碳酸盐岩油藏建模的准确性.图6表1参8     

A Comparative Investigation on Bioactivity and Antibacterial Properties of Sol-Gel Derived 58S Bioactive Glass Substituted by Ag and Zn

Silicon - The bioactive glass systems of xAg2O-SiO2-P2O5-CaO and xZnO-SiO2-P2O5-CaO (x = 2 and 4% mol) were successfully synthesized through sol-gel method. The effect of silver and...     

Computational Fluid Dynamics versus Experiment: An Investigation on Liquid Weeping of Nye Trays

The weeping phenomenon was investigated using some experimental tests and a numerical model. The tests were performed within a 1.22‐m‐diameter pilot‐scale column including two chimney trays and two Nye test trays with an air‐water system. The rates of weeping were measured in the Nye trays with two heights of the weir and a hole area of 5 %. Moreover, the weeping rates in the outlet and inlet halves of the Nye tray and the total weeping rate were calculated. In the next step, an Eulerian‐Eulerian computational fluid dynamics (CFD) technique was used. The results show good agreement between the attained CFD findings and the experimental data.     

Experimentelle und analytische Untersuchung des out‐of‐plane‐Verhaltens von unbewehrten Mauerwerkswänden unter Erdbebenbelastung

Experimental and analytical investigation of the seismic out‐of‐plane behavior of unreinforced masonry walls In addition to the vertical and horizontal load‐bearing in‐plane, masonry must also withstand out‐of‐plane loads that occur in earthquake scenarios. The out‐of‐plane behavior of unreinforced masonry walls depends on a variety of parameters and is very complex due to the strong non‐linearity. Current design methods in German codes and various international codes have not been explicitly developed for out‐of‐plane behavior and contain considerable conservatism. In the present work, shaking‐table experiments with heat‐insulating masonry walls have been conducted to investigate the out‐of‐plane behavior of vertical spanning unreinforced masonry walls. As shown in previous numerical investigations, important parameters are neglected in existing design and analysis models and the out‐of‐plane capacity is underestimated significantly. In the conducted experiments the results of these numerical investigations are verified. Furthermore, the development of an analytical design model to determine the force‐displacement relationship and the out‐of‐plane load‐bearing capacity considering all significant parameters is presented.     

A new linearly constrained minimum variance beamformer for reconstructing EEG sparse sources

Brain source imaging based on EEG aims to reconstruct the neural activities producing the scalp potentials. This includes solving the forward and inverse problems. The aim of the inverse problem is to estimate the activity of the brain sources based on the measured data and leadfield matrix computed in the forward step. Spatial filtering, also known as beamforming, is an inverse method that reconstructs the time course of the source at a particular location by weighting and linearly combining the sensor data. In this paper, we considered a temporal assumption related to the time course of the source, namely sparsity, in the Linearly Constrained Minimum Variance (LCMV) beamformer. This assumption sounds reasonable since not all brain sources are active all the time such as epileptic spikes and also some experimental protocols such as electrical stimulations of a peripheral nerve can be sparse in time. Developing the sparse beamformer is done by incorporating L1-norm regularization of the beamformer output in the relevant cost function while obtaining the filter weights. We called this new beamformer SParse LCMV (SP-LCMV). We compared the performance of the SP-LCMV with that of LCMV for both superficial and deep sources with different amplitudes using synthetic EEG signals. Also, we compared them in localization and reconstruction of sources underlying electric median nerve stimulation. Results show that the proposed sparse beamformer can enhance reconstruction of sparse sources especially in the case of sources with high amplitude spikes.