Designing for parallel fuzzy computing

As the number of fuzzy logic applications increases, demand for faster architectures will grow. Our design for a VLSI fuzzy processor uses fuzzy inference techniques that optimize processing time. Preprocessing that reduces the number of rules to be processed, parallel computation of active rule degrees of activation, and scalability are major features of this architecture. The journal issue contains a concise summary of this article. The complete article is linked to Micro's home page on the World Wide Web (http://www.computer.org/pubs/micro/micro.htm)     

The effect of support morphology on the reaction of oxidative dehydrogenation of ethane to ethylene at short contact times

The oxidative dehydrogenation of ethane is carried out in short contact time reactors over Pt and LaMnO₃ based catalysts supported on a large number of different ceramic substrates (45, 60 and 80 ppi foam monoliths and 200, 400, 600, 900 and 1200 cpsi honeycomb monoliths). Experimental results, obtained under the same conditions at varying the C₂H₆/O₂ ratio, showed that the highest performance in terms of ethylene selectivity and yield is always attained on LaMnO₃ catalysts. Furthermore, the results are significantly influenced by the morphology and cell density of the support, with 45 and 60 ppi foams and 400 and 600 cpsi honeycombs giving the best performance. The experimental results are explained by means of geometrical and fluid dynamic considerations on the support, and by means of a 2D mathematical model, which clearly indicates an optimal intermediate cell density for maximising ethylene selectivity and yield.     

Order vs. Disorder: Cholesterol and Omega-3 Phospholipids Determine Biomembrane Organization

Lipid structural diversity strongly affects biomembrane chemico-physical and structural properties in addition to membrane-associated events. At high concentrations, cholesterol increases membrane order and rigidity, while polyunsaturated lipids are reported to increase disorder and flexibility. How these different tendencies balance in composite bilayers is still controversial. In this study, electron paramagnetic resonance spectroscopy, small angle neutron scattering, and neutron reflectivity were used to investigate the structural properties of cholesterol-containing lipid bilayers in the fluid state with increasing amounts of polyunsaturated omega-3 lipids. Either the hybrid 1-stearoyl-2-docosahexaenoyl-sn-glycero-3-phosphocholine or the symmetric 1,2-docosahexaenoyl-sn-glycero-3-phosphocholine were added to the mixture of the naturally abundant 1-palmitoyl-2-oleyl-sn-glycero-3-phosphocholine and cholesterol. Our results indicate that the hybrid and the symmetric omega-3 phospholipids affect the microscopic organization of lipid bilayers differently. Cholesterol does not segregate from polyunsaturated phospholipids and, through interactions with them, is able to suppress the formation of non-lamellar structures induced by the symmetric polyunsaturated lipid. However, this order/disorder balance leads to a bilayer whose structural organization cannot be ascribed to either a liquid ordered or to a canonical liquid disordered phase, in that it displays a very loose packing of the intermediate segments of lipid chains.     

An optimal decision-making approach for the management of radiotherapy patients

In this paper, novel integer programming formulations are developed for solving the optimal scheduling of patients waiting for radiotherapy treatment. In this specific clinical domain, the suitable management and control of a patients’ waiting list strongly affect both the quality of the therapeutical outcome, in terms of effectiveness, and the cost-saving use of the overall therapeutical resources, in terms of efficiency. The proposed models allow the best scheduling strategy to be devised by taking into account the quality of the health care service offered to the patient as well as the status and the preferences of the patient. The computational experiments, carried out on realistic scenarios and considering real data, are very promising and show the efficiency and robustness of the proposed models to address the problem under consideration.     

Controlled Growth of ZnO Nanowires and Their Optical Properties

This article surveys recent developments in the rational synthesis of single‐crystalline zinc oxide nanowires and their unique optical properties. The growth of ZnO nanowires was carried out in a simple chemical vapor transport and condensation (CVTC) system. Based on our fundamental understanding of the vapor–liquid–solid (VLS) nanowire growth mechanism, different levels of growth controls (including positional, orientational, diameter, and density control) have been achieved. Power‐dependent emission has been examined and lasing action was observed in these ZnO nanowires when the excitation intensity exceeds a threshold (∼40 kW cm^–2). These short‐wavelength nanolasers operate at room temperature and the areal density of these nanolasers on substrate readily reaches 1 × 10¹⁰ cm^–2. The observation of lasing action in these nanowire arrays without any fabricated mirrors indicates these single‐crystalline, well‐facetted nanowires can function as self‐contained optical resonance cavities. This argument is further supported by our recent near‐field scanning optical microscopy (NSOM) studies on single nanowires.     

Reliability enhancement with the aid of transient infrared thermal analysis of smart Power MOSFETs during short circuit operation

The usage of novel measurement techniques enhances the capabilities of researchers and power device manufacturers to understand and address reliability problems in novel Smart Power Devices. Along this line of argument, this work describes a method to improve the reliability of the smart Power MOSFET devices by design. The design optimization process involves Silicon layout, interconnections, packaging and protection strategy as well. Accurate thermal transient analyses, made possible by the unique features of a custom infrared radiometric microscope experimental setup which allows dynamic temperature detection with a bandwidth of 1 MHz over the chip area, indicated the way to minimize peak temperature and to verify the effect of the optimization.     

Influence of loading method and stocking density during transport on meat and dry-cured ham quality in pigs with different halothane genotypes

The effect of loading method and stocking density in transit on meat and dry-cured ham quality was investigated in pigs with different halothane genotypes. A total of 507 Italian heavy pigs, supplied by two farms, were loaded by ramp or lift and transported unmixed for 35–55 min to the abattoir at a stocking density of either <0.4 or >0.6m² per 100 kg pigs. After overnight lairage in separate pens with free access to water, the pigs were slaughtered. Halothane genotype was assessed post mortem. Four hundred and thirty-nine pigs had a homozygous dominant (NN) genotype and 68 pigs were heterozygous (Nn). Carcass skin damage, meat quality traits and ham curing parameters were evaluated. Loading method and stocking density showed a negligible effect on meat and dry-cured ham quality while the predominant factor affecting these was the halothane genotype. Nn pigs produced meat with a faster rate of pH fall and lower water holding capacity as well as ham with higher weight losses in salting and greater incidence of defects in the dry-cured product. There were insignificant interactions between halothane genotype and loading method or stocking density. Overall, irrespective of pre-slaughter treatment, the Nn pigs were less suitable for the production of high quality products such as dry-cured ham.     

Immersive electronic books for surgical training

Immersive electronic books (IEBooks) for surgical training will let surgeons explore previous surgical procedures in 3D. The authors describe the techniques and tools for creating a preliminary IEBook, embodying some of the basic concepts.     

A C/I advantageous satellite system configuration for land mobile applications

A satellite system based on the frequency scanning concept has been recently assessed for L‐band land mobile communications. The study – promototed by ESA/ESTEC for an European application mission – has reached an advanced electrical design phase. The selected configuration is particularly advantageous in terms of Carrier‐to‐Intermodulation ratio (C/I) performance, which constitutes a requirement of key‐importance in the envisaged user applications. The advantage in C/I is due to the proper choice of the on‐board transmitter configuration, which adopts power module pairs where the overall power demand is evenly distributed. The consequent improved C/I is then achievable at both transmitter and radiated far field level. The present paper aims a contribution to the design methodology of frequency scanning satellite systems, by joining two key‐aspects: in fact an analytical approach is proposed to demonstrate the C/I advantage achievable through frequency scanning satellite systems and the methodology is applied to a concrete example, the ESA/ESTEC system, whose feasibility has been fully proved in previous studies. The analysis is performed both at transmitter level and in the far field. The main results achieved are hereinafter presented. This revised version was published online in June 2006 with corrections to the Cover Date.