The weight hierarchies of some product codes

We determine the weight hierarchies of the product of an n-tuple space and an arbitrary code, the product of an m-dimensional even-weight code and the [24,12,8] extended Golay code, and the product of an m-dimensional even-weight code and the [8,4,4] extended Hamming code. The conjecture d_r=d*_r is proven for all three cases     

Thermally stable crosslinked NLO materials based on maleimides

A series of thermally stable second-order nonlinear optical (NLO) polymeric materials based on bismaleimide chemistry have been developed. Two maleimide containing chromophores with excellent thermal stability were incorporated into the bismaleimide polymer matrices to form interpolymer networks. Moreover, a full interpenetrating polymer network (IPN) was formed through simultaneous addition reaction of the bismaleimide, and sol-gel process of alkoxysilane dyes (ASD). Atomic force microscopy results indicate that the inorganic networks are distributed throughout the polymer matrices on the molecular scale. The silica particle sizes are well under 200 nm. Second harmonic coefficients, d₃₃ of 6.9-57.0 pm/V have been obtained for the organic and organic/inorganic materials. Excellent temporal stability was obtained for these NLO materials at 100 °C. The dynamic thermal and temporal stabilities of the IPN system were much better than those of the crosslinked organic systems.     

The interface properties of Ar-annealed nitrided oxides

The gate–oxide interface properties as well as the oxide–substrate interface properties of MOS capacitors with various nitridation conditions were studied. For comparison, samples were annealed in O₂ and Ar ambients. Experimental results show that both annealing ambients yield similar interface density and electron traps on the oxide–substrate interface. However, Ar-annealed nitrided oxides have higher capacitance and fewer electron traps on the gate–oxide interface.     

Androgen receptor YAC transgenic mice carrying CAG 45 alleles show trinucleotide repeat instability

BACKGROUND: The functional significance of the anterograde and retrograde filling of coronaries on angiography is controversial. METHODS AND RESULTS: Eighteen patients with 27 severe lesions (> 85% diameter stenosis) after previous extensive myocardial infarction were selected. The left ventricle was divided into 33 segments for regional comparison of epicardial flow (as assessed by angiography) and tissue perfusion as well as metabolism (as measured by 13NH3- and 18FDG-PET). Viability was defined as normal perfusion (> 80% relative of maximum 13NH3 activity) or mismatch defect (> 1.2 metabolism/flow ratio). A method has been developed to register the 'lesion predicted region', determined on the basis of angiography, in the same polar map as derived from the positron emission tomography data. Distal to the lesion, the anterograde epicardial flow was evaluated by Thrombolysis in Myocardial Infarction (TIMI) criteria (TIMI flow 0-3), and retrograde filling was graded on a 0-3 scale (collateral grade 0-3). TIMI flow grade and retrograde collateral grade in every lesion predicted region segment were summed to indicate the total segmental epicardial flow. Out of the 594 segments, 369 were associated with a severe lesion. Among them, significantly higher average perfusion and metabolic activities were found in segments of good epicardial filling (summed epicardial flow > or = 3) than in the territories of limited epicardial flow (summed score < 3): 65.4 +/- 17% vs 45.6 +/- 10 (P = 0.001%) and 68.6 +/- 16% vs 47.4 +/- 11% (P = 0.0004), respectively. However, when we analysed the predictive value of angiographically detectable good epicardial flow for positron emission tomography viability criteria then the positive predictive value was found to be as low as 0.5, while the negative predictive value was considerably higher (0.82). CONCLUSION: After myocardial infarction, angiographically detectable limited epicardial flow reveals scarred segments while good epicardial contrast filling does not necessarily indicate maintenance of nutritive function.     

The performance evaluation of spatial–temporal algorithms in W‐CDMA systems

Differing from FDMA, TDMA, and CDMA, space division multiple access (SDMA) uses space resources to improve communication system performance. Utilizing the smart antenna system is an approach to realize the SDMA technique. Smart antenna systems using the beamforming technique can reduce the co‐channel interference and multipath fading to increase the channel capacity and communication quality. In this study the smart antenna system and rake receiver are integrated. The performance of spatial–temporal structure applied to the W‐CDMA system is evaluated. From the cumulative distribution function simulation results, W‐CDMA system with spatial–temporal algorithm can exactly provide SINR gain to improve the system performance and capacity. Copyright © 2005 John Wiley & Sons, Ltd.     

Integrated Planar HTS SQUID Gradiometer for NDE Application

The performance of a SQUID NDE probe with integrated planar SQUID gradiometers was compared to that with an electronic axial SQUID gradiometer. A circular excitation coil was used for the SQUID NDE probe with the planar gradiometer, whereas a differential excitation coil was adopted for the one with the axial gradiometer. These NDE systems are used to detect a buried flaw in aluminum plates, and the phase-depth relations of the buried flaw were found to show similar linear dependences. Overall, the SQUID NDE system with the planar gradiometer is relatively simple and practical for unshielded operations.     

Auto-tune system using single-run relay feedback test and model-based controller design

In this paper, a systematic approach for auto-tune of PI/PID controller is proposed. A single run of the relay feedback experiment is carried out to characterize the dynamics including the type of damping behavior, the ultimate gain, and ultimate frequency. Then, according to the estimated damping behavior, the process is classified into two groups. For each group of processes, model-based rules for controller tuning are derived in terms of ultimate gains and ultimate frequencies. To classify the processes, the estimation of an apparent deadtime is required. Two artificial neural networks (ANNs) that characterize this apparent deadtime using the ATV data are thus included to facilitate this estimation of this apparent deadtime. The model-based design for this auto-tuning makes uses of parametric models of FOPDT (i.e. first-order-plus-dead-time) and of SOPDT (i.e. second-order-plus-dead-time) dynamics. The results from simulations show that the controllers thus tuned have satisfactory results compared with those from other methods.     

Quick Seismic Response Estimation of Prestressed Concrete Bridges Using Artificial Neural Networks

Seismic early warning has been very important and has become feasible in Taiwan. Perhaps because of the lack of quick and reliable estimations of the induced structural response, however, the triggering criteria of almost all of the existing earthquake protection or early warning systems in the world are merely based on the collected or estimated data of the ground motion, without any information regarding the structural response. This paper presents a methodology of generating quick seismic response estimations of a prestressed concrete (PC) bridge using artificial neural networks (ANNs), which may be incorporated in a seismic early warning system for the bridge. In the methodology ANNs were applied to model the critical structural response of a PC bridge subjected to earthquake excitation of various magnitudes along various directions. The objective was to implement a well-trained network that is capable of providing a quick prediction for the critical response of the target bridge. The well-known multilayer perception (MLP) networks with back propagation algorithm were employed. A simple augmented form of MLP that can be quantitatively determined was proposed. These networks were trained and tested based on the analytical data obtained from the nonlinear dynamic finite fiber element analyses of the target PC bridge. The augmented MLPs were found to be much more efficient than the MLPs in modeling the critical bending moments of the piers and girder of the PC bridge.     

Effects of reactive low‐profile additives on the properties of cured unsaturated polyester resins. I. Volume shrinkage and internal pigmentability

The effects of reactive poly(methyl methacrylate) (PMMA) and poly(vinyl acetate)‐block‐PMMA as low‐profile additives (LPAs) on the volume shrinkage characteristics and internal pigmentability for low‐shrink unsaturated polyester (UP) resins during curing at 110°C were investigated. These reactive LPAs, which contained peroxide linkages in their backbones, were synthesized by suspension polymerization with polymeric peroxides as initiators. Depending on the LPA composition and molecular weight, the reactive LPAs led to a considerable volume reduction or even to a volume expansion after the curing of styrene (ST)/UP/LPA ternary systems; this was attributed mainly to the expansion effects of the LPAs on the ST‐crosslinked polyester microgel structures caused by the reduction in the cyclization reaction of the UP resin during curing as well as to the repulsive forces between the chain segments of UP and LPAs within the microgel structures. The experimental results were explained by an integrated approach of measurements for the static phase characteristics of the ST/UP/LPA system, reaction kinetics, cured sample morphology, and microvoid formation with differential scanning calorimetry, scanning electron microscopy, optical microscopy, and image analysis. With the aid of the Takayanagi mechanical model, the factors leading to both a good volume shrinkage control and acceptable internal pigmentability for the molded parts were also explored. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 264–275, 2005     

Real-time traffic parameter extraction using entropy

A vision-based traffic monitoring system that can perform real-time traffic parameter extraction is proposed. The entropy measurement, which is commonly adopted as an important feature to describe the degree of disorder in thermodynamics, is used as an underlying feature in this work. Based on an entropy measurement, a number of important traffic parameters, such as traffic flow, space mean speed and traffic queue, can be determined in real time. The experimental results clearly show that the proposed system is highly effective.