Deterministic quantization theory applied to ADC testing

ADC testing represents one of the most complex and active fields of expertise related to modern instrumentation and measurement. Special care has to be arranged for defining evaluation parameters to access ADC performance. Traditional testing methods based on the well-known accuracy figures (differential and integral non-linearities, gain and offset errors, missing codes, etc. [1–3], reach their limits when dealing with dynamic testing. More advanced statistical methods tried to overcome these limits but the results were not always satisfactory [4–6]. Different methodologies to test ADC performance have been proposed in recent years in order to overcome limits imposed by classical testing procedures. Among the more recent results the Walsh transform-based methods [7] introduced the full dynamic testing condition, considering both the sampling and signal frequencies as evaluation parameters. This technique cannot be considered optimal because of the complexity of the parameter representation. A more convenient approach, from this point of view, can be found by starting from a completely different mathematical basis, by applying the deterministic theory of quantization phenomena. This work opens the way to a dedicated theory of ADC testing when Fourier transform analysis based on deterministic quantization is adopted.     

Effects of dietary carbohydrate sources on degradation kinetics of nitrogen from plant protein sources in the rumen

The effects of the nature of carbohydrate source on in sacco protein degradation of 15 samples of plant protein sources were studied in four mature fistulated rams fed a control diet (C) of meadow hay and soyabean meal (83:15 on dry matter basis) and three diets in which 36, 34 or 40% of diet dry matter was sugar beet pulp, maize or wheat (diets P, M and W respectively). Degradation parameters were estimated from the exponential equation p = a + b[1 ? exp(?ct)]. Diet composition significantly affected (P < 0.001) all the degradation parameters, the effect being more pronounced on the degradation rate (c). This parameter was stimulated (P < 0.05) by beet pulp but depressed (P < 0.05) by cereal inclusion in the diets, in particular when animals were fed the W diet (4.46, 5.65, 3.74 and 3.05% h^?1 for the C, P, M and W diets respectively). An interaction effect between carbohydrate source and incubated plant protein sources was observed (P < 0.001). The reason(s) for these differential effects were not elucidated. The practical consequences of these findings are discussed. Copyright © 2005 Society of Chemical Industry     

Surface acidic properties of alumina-supported niobia prepared by chemical vapour deposition and hydrolysis of niobium pentachloride

Niobia–aluminas were prepared by chemical vapour deposition at 150°C of niobium pentachloride on the surface of γ-aluminas calcined at different temperatures and with controlled degrees of hydration, followed by hydrolysis with water vapour at 150°C and a thermal treatment with steam at 440°C aimed at removing surface chloride contamination. The samples were characterised with respect to chemical composition, surface area, acidity by temperature-programmed desorption of ammonia, nature of acid sites by infrared spectroscopy of adsorbed pyridine and catalytic activity at 370°C in the dealkylation of cumene.

The results showed that, for each alumina calcination temperature, the catalysts with the lowest niobium content have a higher density of acid sites than the alumina support, but the acidity decreased, within each series with an increase in the niobium content. Comparatively to the TPD results, catalytic activity in cumene dealkylation was much more sensitive to the history and composition of the samples. The niobia-alumina samples were much less active than the alumina support, but this was most likely due to the severe hydrothermal treatment for chlorine removal, since their activity was close to that of an alumina submitted to the same treatment. A strong decrease in the acidic activity was observed with increase in the niobium content. A sample of pure niobium oxide had a much higher activity than the niobia-alumina samples. Brønsted acidic sites could only be observed by the IR spectra of adsorbed pyridine on the surface of the pure niobium oxide sample.     

A decision support tool coupling a causal model and a multi-objective genetic algorithm

A significant class of decision making problems consists of choosing actions, to be carried out simultaneously, in order to achieve a trade-off between different objectives. When such decisions concern complex systems, decision support tools including formal methods of reasoning and probabilistic models are of noteworthy helpfulness. These models are often built through learning procedures, based on an available knowledge base. Nevertheless, in many fields of application (e.g. when dealing with complex political, economic and social systems), it is frequently not possible to determine the model automatically, and this must then largely be derived from the opinions and value judgements expressed by domain experts. The BayMODE decision support tool (Bayesian Multi Objective Decision Environment), which we describe in this paper, operates precisely in such contexts. The principal component of the program is a multi-objective Decision Network, where actions are executed simultaneously. If the noisy-OR assumptions are applicable, such a the model has a reasonably small number of parameters, even when actions are represented as non-binary variables. This makes the model building procedure accessible and easy. Moreover, BayMODE operates with a multi-objective approach, which provides the decision maker with a set of non-dominated solutions, computed using a multi-objective genetic algorithm. Ivan Blecic is Assistant Professor of Economic Appraisal and Evaluation at the Faculty of Architecture in Alghero (University of Sassari, Italy) and member of Interuniversity Laboratory of Analysis and Models for Planning (LAMP). He received a Ph.D. in Planning and Public Policies in 2005 from IUAV University of Venice where he has also been a research fellow at the Department of Planning. His current research interests include analysis and modelling for planning, evaluation techniques and modelling, decision support systems and methods for public participation. Arnaldo Cecchini graduated cum laude in Physics at the University of Bologna in 1972. He is Professor of Analysis of Urban Systems at the Faculty of Architecture in Alghero (University of Sassari), Director of the Urban and Environmental Planning Course, Vice-Dean of the Faculty of Architecture in Alghero and Director of the Interuniversity Laboratory of Analysis and Models for Planning - LAMP. He is the author of more than 100 articles and papers published in books and refereed journals and is an expert in techniques of urban analysis and for public participation: simulation, gaming simulation, cellular automata, scenario techniques. Giuseppe A. Trunfio gained a Ph.D. in Computational Mechanics in 1999 at the University of Calabria, Italy. He has been a research fellow at the Italian National Research Council where he has worked extensively on the application of parallel computing to the simulation of complex systems. He is Assistant Professor of Computer Engineering at the Department of Architecture and Planning of the University of Sassari and his current research interests include decision support, probabilistic models, neural networks, evolutionary computation and cellular automata.     

Oil shale solid waste recycling in the development of new silica fillers for elastomeric composites

The production of Brazilian shale oil gives rise to 6600 ton/day of a solid waste of retorted shale, and larger amounts of dolomitic waste rock are generated during mining. Two vitreous materials were obtained through the melting of different proportions of these two wastes. By leaching these materials with hydrochloric acid at 90°C, two different kinds of silicas (powder and gel, both amorphous) with specific surface areas reaching up to ～ 420 m²/g were generated. These silicas were further modified through an Ostwald‐ripening type of treatment in ammonium hydroxide solution at 80°C. The process eliminated almost completely the deleterious micropores. The obtained silicas were evaluated as reinforcing fillers for SBR‐1502. The employment of one of the modified silicas gave rise to a composite with better mechanical properties than those displayed by the one with untreated silica. Scanning electronic microscopic observation disclosed the existence of great morphological differences between these silicas. Apparently, the aging treatment gave rise to the production of better anchoring sites for the elastomer molecules. NMR studies also showed the reduction of the silanol content of the treated silica. The fracture surface of the composite disclosed a good wetting of this silica by the elastomeric matrix. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2856–2867, 2001     

Cumene hydrocracking and thiophene HDS on niobia-supported Ni, Mo and Ni–Mo catalysts

Results are reported on the XPS characterization and catalytic activity in cumene hydrocracking (2.8 MPa, 623 K) and thiophene HDS (2.8 MPa, 523–573 K) of sulfided Ni, Mo and Ni–Mo catalysts supported on alumina and on pure and phosphated niobia. From the XPS results, evidence was obtained for the formation of a surface niobium sulfide with stoichiometry close to NbS₂ during catalyst sulfidation. Sintering of supported nickel during sulfidation occurred to a much smaller extent with the niobia-supported catalysts than with the alumina-supported ones. The dispersion of alumina-supported molybdenum was little influenced by sulfidation, whereas, with the niobia supports, the molybdenum surface concentration increased with sulfidation. With the alumina support, the Ni–Mo combination caused the dispersion of the sulfided nickel to be improved, possibly due to formation of a NiMoS phase. This was not observed with the niobia-supported catalysts.

Reasonable linear correlations were also found between the intrinsic activity for cumene hydrocracking and the amount of sulfided niobium in the catalysts, but the catalysts supported on phosphated niobia had a higher intrinsic activity than the ones supported on pure niobia. In thiophene HDS, the activity of the niobia-supported nickel catalysts was much larger than the activity of the alumina-supported ones. The activity of the niobia-supported molybdenum catalysts was smaller than that of the alumina-supported catalyst. With the bimetallic catalysts, little or no synergy was observed with the niobia-supported catalysts, in sharp contrast with the alumina case.     

A new method for testing timed systems

Devising formal techniques and methods that can automatically generate test suites for timed systems has remained a challenge. In this paper Timed Input/Output Automata (TIOA) are used as a formal specification model for timed systems. This work proposes and proves the correctness of a new and more general discretization method that can be used to obtain grid automata corresponding to specification TIOA, using almost any granularity of interest. Such flexibility to find a suitable granularity opens the possibility for a more compact construction of grid automata. It is also shown how test purposes can be used together with the specification TIOA in order to generate grid automata that capture the behavior of both the specification and the test purpose. From such grid automata one can algorithmically extract test suites that can be used to verify whether given implementations adhere to the specification and reflect the properties modeled using the test purposes. Copyright © 2011 John Wiley & Sons, Ltd.     

Satisfactory video dissemination on FANETs based on an enhanced UAV relay placement service

The user experience on watching videos transmitted by a flying ad hoc networks (FANETs) should always be satisfactory even under influence of topology changes in reason of the unmanned aerial vehicles (UAVs) mobility. However, one of the main challenges to route packets in FANETs is how to mitigate the effects of UAV mobility to preclude communication flaws, delays, and void area, which hence increase the packet loss over video transmissions. In this way, routing protocols require an efficient relay placement service to find out the ideal location for UAVs that act as relay nodes, and thus mitigating the effects of UAV movements on the quality of experience (QoE) of transmitted videos. In this article, we introduce a massive analysis of our proposed relay placement mechanism, called MobiFANET, in order to diagnose the impact of videos with different characteristics on the QoE and route failure. We also present detailed information about the MobiFANET mechanism, as well as the contributions of each component on the routing performance. Simulation results show how MobiFANET works jointly with a routing protocol for satisfactory multimedia transmission, where it provides better QoE and a reduction of the number of route failures compared to existing routing protocols.     

Cellular automata simulation of urban dynamics through GPGPU

In recent years, urban models based on Cellular Automata (CA) are becoming increasingly sophisticated and are being applied to real-world problems covering large geographical areas. As a result, they often require extended computing times. However, in spite of the improved availability of parallel computing facilities, the applications in the field of urban and regional dynamics are almost always based on sequential algorithms. This paper makes a contribution toward a wider use in the field of geosimulation of high performance computing techniques based on General-Purpose computing on Graphics Processing Units (GPGPU). In particular, we investigate the parallel speedup achieved by applying GPGPU to a popular constrained urban CA model. The major contribution of this work is in the specific modeling we propose to achieve significant gains in computing time, while maintaining the most relevant features of the traditional sequential model.