CMM uncertainty analysis with factorial design

The purpose of this research is to present a method to estimate the Coordinate Measuring Machine (CMM) measurement uncertainty. The approach is based on a performance test using a ball bar gauge and a factorial design technique. A factorial design was applied to carry out a performance test and to investigate CMM errors associated to orientation and length in the work volume. The CMM measurement uncertainty was estimated with components of variance obtained after statistical analysis of variance applied to volumetric measurement errors. An application was performed with a Moving Bridge CMM and the results were compared to the volumetric performance test proposed by ANSI/ASME B89.4.1 standard. The results showed that the proposed method is suitable to investigate CMM hardware performance and determine the contribution of machine variables to measurement uncertainty.     

A negotiation-based scheme for service level pricing for wireless access

The Next Generation Network (NGN) will enable service providers to offer broadband services with differentiated quality to their subscribers. In this way, the providers will be able to satisfy and retain the critical segment of the top-demanding customers, who generate the largest share of the provider’s revenues. However, service pricing is as important as service quality. In order to offer competitive prices, bilateral per service negotiation between the customer and the supplier is an interesting practical solution that can provide better results than rigid offers based on fixed price-rate lists. In the application scenario of Broadband Wireless Access, the supplier can adapt its offer of wireless access bandwidth to the dynamics of customer-generated traffic, giving more bandwidth per session when traffic is low and less bandwidth per session when traffic is high. We present and study the performance of an algorithm for automatic service level pricing in which two agents negotiate over the service transmission rate and the price on behalf of the user and of the provider. The performance of the proposed negotiation scheme is evaluated with simulations. The paper also compares our algorithm to the fixed-price scheme and to an auction-based strategy based on the Vickrey scheme.     

X-ray micro tomography and image analysis as complementary methods for morphological characterization and coating thickness measurement of coated particles

This work demonstrates the potentiality of X-ray micro tomography as a powerful tool for morphological characterization of coated particles and, in particular, of their coating layer. X-ray micro tomography provides a high level of details at both micro and macro-scale. It was, in this work, used in the determination of density, porosity, surface/volume ratio, and thickness of the coating layer. Special emphasis was put on evaluation of the adhesion core/coating shell due to its strong influence on the acceptance and goodness of the final coated compound. Different definitions of coating thickness are evaluated. The variance of these properties is assessed within particles and between particles. A novel protocol was developed in order to segment the coating shell out from the core particles. The segmented out images were used to create 3D models of such coating shells. General aspects of theses models are discussed. The potential and limitations of X-ray micro tomography are finally highlighted based on the experimental work. Image analysis was used to determine the coating thickness applied on the core particles as complementary and reference method. As case study, two series of coated particles, prepared using top-spray fluidized bed coater, were obtained, each one employing three standard well-know coating agents.     

Simultaneous optimization of tracking performance and accommodation of sensor faults

Sensor performance can be monitored using SElf-VAlidating (SEVA) devices. These supply the user with an estimate of the measurement reliability as well as the measurement value. This paper presents a sensor fault-accommodation strategy exploiting information regarding the measurements quality, such that indices of dynamic performance and noise rejection are continuously optimized as the sensor reliabilities vary. An important result proved in this paper is that the minimization of these two indices is completely decoupled and hence noise rejection can be maximized without trading-off dynamic performance. Two further fault-accommodation strategies based on interpolation are then derived with the intent of trading-off optimality for computational simplicity and transparency. Numerical examples are provided showing that one of these ( stabilizing interpolation ) is particularly attractive, being only negligibly suboptimal for the examples considered and much better than a 'do-nothing' strategy.     

A Current-Mode Hysteretic Winner-take-all Network, with Excitatory and Inhibitory Coupling

Winner-take-all (WTA) circuits are commonly used in a wide variety of applications. One of the most used current-mode WTA designs is the one originally proposed by Lazzaro et al. [1]. Several extensions to this design have been suggested in the past. In this paper we present a variant of this current-mode WTA circuit, containing all of the enhancements previously proposed, together with new additional modifications that endow it with interesting hysteretic and lateral inhibition and excitation properties. We compare the performance of this WTA circuit to the original WTA design, providing experimental data obtained from a VLSI chip containing both types of circuits, designed using closely matched layouts. We derive analytically the response properties of the circuit's lateral diffusion network, pointing out the differences to previously proposed diffusion networks, and present experimental data confirming the theoretical predictions. We also describe application domains that can best exploit these types of hysteretic WTA circuits.     

Renewable energy benefits with conversion of woody residues to pellets

In the frame of an Interreg IIIC Network-Operation named RegEnergy, that unites 18 partners from 11 countries of Europe, the feasibility of using the woody by-products for heating purpose in a typical Mediterranean region was investigated. Focusing on the Abruzzo Region as representative sample area, it came out that a significant amount of the above mentioned renewable energetic material is annually available as a consequence of well-consolidated and economically significant agro-industrial activities, forest maintenance and industrial wood production and transformation. In particular, it was found that the total amount of woody residues, as dry substance, are more than 700 kt/a, with 30% resulting from pruning activities related to the cultivation of about 360 km² of vineyards and 450 km² of olive-groves; these residues are concentrated in the hilly part of the region close to the Adriatic sea coast. Starting by this pleasant situation, the feasibility of a properly localized wood pellets production plant was supported by both the economic and energetic analysis. Additional suggestions related to optimal plant localization and to the best use of the woody pellets as substitute of natural gas for heating purposes were reported along with the positive impact of the whole action on the quality of the environment and on the recovery of soil fertility.     

Statistical analysis on Sicilian olive oils

A robust multivariate statistical procedure applied to an accurate gas chromatography (GC) analysis was used to analyze 1004 monovarietal and multivarietal Sicilian extra virgin olive oils coming from 22 cultivars of different geographical areas of Sicily and collected in nine years (1993, 1995, 1996, 1997, 1998, 1999, 2000, 2001 and 2002). The effect of the cultivar, of pedoclimatic conditions as well as of the year of harvesting on the olive oil fatty acid composition and therefore on their classification was investigated. Oleic, linoleic and palmitic fatty acids, important for the nutritional properties of an olive oil, showed a crucial rule in the characterization of olive oils.