Low-complexity maximum-likelihood decoder for four-transmit-antenna quasi-orthogonal space-time block code

This letter proposes a very low-complexity maximum-likelihood (ML) detection algorithm based on QR decomposition for the quasi-orthogonal space-time block code (QSTBC) with four transmit antennas, called the LC-ML decoder. The proposed algorithm enables the QSTBC to achieve ML performance with significant reduction in computational load for any high-level modulation scheme.     

Microwave power amplification with InP f.e.t.s

InP f.e.t.s were fabricated from v.p.e. layers, with an Al gate of 1.5 ?m × 308 ?m. The power output at 9 GHz, with 4 dB gain, was 1.15 W/mm gate width. This result is believed to be higher than the best published results obtained with equivalent GaAs f.e.t. structures.     

ECG beat recognition using fuzzy hybrid neural network

This paper presents the application of the fuzzy neural network for electrocardiographic (ECG) beat recognition and classification. The new classification algorithm of the ECG beats, applying the fuzzy hybrid neural network and the features drawn from the higher order statistics has been proposed in the paper. The cumulants of the second, third, and fourth orders have been used for the feature selection. The hybrid fuzzy neural network applied in the solution consists of the fuzzy self-organizing subnetwork connected in cascade with the multilayer perceptron, working as the final classifier. The c-means and Gustafson-Kessel algorithms for the self-organization of the neural network have been applied. The results of experiments of recognition of different types of beats on the basis of the ECG waveforms have confirmed good efficiency of the proposed solution. The investigations show that the method may find practical application in the recognition and classification of different type heart beats.     

BPH Sensor Network Optimization Based on Cellular Automata and Honeycomb Structure

Mobile Networks and Applications - The brown planthopper (BPH) is a crucial pest of rice in tropical zones like the Mekong Delta of Vietnam. It economically causes severe loss to the rice harvest...     

On a combination of ground-hook controllers for semi-active tuned mass dampers

This study proposes a semi-active on-off damping controller that is a mix of three conventional ground-hook controllers for semi-active tuned mass damper systems. Three conventional ground-hook controllers are shown to be effective only in a certain frequency range. By taking advantage of all three ground-hook controllers, the mixed controller shows its better performance. More-over, we found an analytical solution of the harmonic vibration of the semi-active controlled system. The accuracy of the analytical solution and the superior performance of the proposed controller are verified by the numerical simulations.     

Fabrication of photocatalytic PVA–TiO<Subscript>2</Subscript> nano-fibrous hybrid membrane using the electro-spinning method

Nano-fiber membranes hold great promise for use in filtration applications. In this study, a photocatalytic polyvinyl alcohol (PVA)/TiO₂ composite polymer membrane was successfully synthesized at different TiO₂ concentrations (20, 30, 40, and 50%) using the electro-spinning method. The parameters of electro-spinning including electrical field, tip-to-collector distance, and feed rate were optimized for fabrication process. The diameter of the electro-spun PVA–TiO₂ fibers and average size of the TiO₂ nano-particles loaded in the PVA nano-fibers ranged from 100 to 150 nm and 15 to 30 nm, respectively. X-ray diffraction analysis indicated that the main crystal structure was of the anatase type even though small rutile peaks were also observed for the PVA–TiO₂ membrane. TiO₂ nano-particles were embedded in the PVA fiber and were dispersed linearly along the fiber direction. As the amount of TiO₂ loaded in PVA increased, the tensile strength also increased while the tensile strain significantly decreased. Also, when the TiO₂ content was increased from 20 to 50%, the photocatalytic activity of the PVA–TiO₂ membranes increased.     

Manufacturing,assembly, and testing of scaled,historic masonry for one-gravity,pseudo-static,soil-structure experiments

In many model-scale experiments, geometric scaling is upheld but kinematic and/or dynamic similitude is not because of the difficulty in manufacturing and assembling small models. This paper describes scaling, manufacturing, assembly, and testing of 1/10th scaled historic masonry materials for one-gravity, pseudo-static, soil-structure testing. Prototype selection, manufacturing limitations, constructability constraints, and testing decisions are presented, alongside details related to model construction. Compressive, tensile, and shear capacities of one-tenth scale prototype values, as well as failure mechanisms, were achieved by adopting traditional brick extrusion and firing methods, in conjunction with modifying mortar products developed for historic restoration. When scaled-masonry structures were subjected to adjacent excavation, resulting displacement and damage patterns were consistent with full-scale, field observations.     

Strength prediction and failure modes of concrete specimens subjected to the split test

This paper deals with modelling and test of concrete specimens subjected to the Brazilian split test. Based on the fictitious crack concept, a simple model for the crack propagation process in the splitting plane is developed. From the model, it is possible to determine the distribution of residual tensile strength as crack propagation take place. The residual tensile strength is thereafter used in a rigid plastic analysis of the splitting failure. Based on this combined approach, the ultimate load may either be governed by crack propagation or by a plastic failure, which then terminates the crack growth process. It is shown that the model is able to replicate a number of experimental observations. This includes size effect and influence of loading width.     

Magnetic Properties of Fe 3 O 4 Nanoparticles Synthesized by Coprecipitation Method

In this paper, we elucidate several specific magnetic properties of Fe ₃ O ₄nanoparticles synthesized by coprecipitation method. The characterizations by X-ray diffraction technique (XRD) and scanning electron microscopy (SEM) showed the particles to be of spinel structure and spherical shapes whose diameter could be controlled in the range from 14 to 22 nm simply by adjusting the precursor salts concentration and coprecipitation temperature. Magnetic properties of the Fe ₃ O ₄ nanoparticles measured by using vibration sample magnetometer (VSM) indicated the saturation magnetization and blocking temperature to increase with the particles size. Fe ₃ O ₄ nanoparticles with crystal size smaller than 22 nm exhibits superparamagnetic behavior at room temperatures. Characteristic magnetic parameters of the particles including saturation magnetization, effective anisotropy constant, and magnetocrystalline anisotropy constant have been determined. The observed decrease of saturation magnetization was explained on the base of core-shell model. A simple analysis indicated that the shell thickness decreases with an increase in particle size.     

Low-noise two-dimensional electron gas FET

Two-dimensional electron gas FETs (TEGFETs) have been fabricated on an N-AlGaAs-GaAs heterojunction. Microwave results at 10 GHz are: NF=2.3 dB, Gass=10.3 dB and Gmax=13.2 dB. These first results obtained on nonoptimised material and processing suggest that TEGFET can be superior to a conventional GaAs FET.