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51.
52.
Michela Antonelli Pietro Ducange Beatrice Lazzerini Francesco Marcelloni 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2011,15(10):1981-1998
Interpretability of Mamdani fuzzy rule-based systems (MFRBSs) has been widely discussed in the last years, especially in the
framework of multi-objective evolutionary fuzzy systems (MOEFSs). Here, multi-objective evolutionary algorithms (MOEAs) are
applied to generate a set of MFRBSs with different trade-offs between interpretability and accuracy. In MOEFSs interpretability
has often been measured in terms of complexity of the rule base and only recently partition integrity has also been considered.
In this paper, we introduce a novel index for evaluating the interpretability of MFRBSs, which takes both the rule base complexity
and the data base integrity into account. We discuss the use of this index in MOEFSs, which generate MFRBSs by concurrently
learning the rule base, the linguistic partition granularities and the membership function parameters during the evolutionary
process. The proposed approach has been experimented on six real world regression problems and the results have been compared
with those obtained by applying the same MOEA, with only accuracy and complexity of the rule base as objectives. We show that
our approach achieves the best trade-offs between interpretability and accuracy. 相似文献
53.
Vincenzo Calemma Chiara Gambaro Wallace O. Parker Rosa Carbone Roberto Giardino Pietro Scorletti 《Catalysis Today》2010,149(1-2):40-46
A light cobalt catalyzed Fischer–Tropsch (FT) wax was subjected to hydrocracking in the range of temperature 319–351 °C and hydrogen pressure between 3.5 and 6.0 MPa. The catalyst used was platinum on amorphous silica–alumina. Hydrocracking reaction led to an increase of middle distillate yield up to 85% with a contemporary increase of iso-paraffins concentration which resulted in a remarkable improvement of cold flow properties of the products. The freezing point of C10–C14 fraction passed from ?23 to ?45 °C while the pour point of C15–C22 fraction decreased from 13 to ?23 °C. The latter fraction displayed high cetane numbers ranging between 75 and 80. Changes in carbon distribution and molecular structure of products during hydrocracking have been rationalized in the light of the accepted hydrocracking mechanism where n-paraffins undergo to consecutive isomerization reactions leading to isomers with progressively higher branching degree and concomitant cracking reaction. Experimental evidences support the view that apparent reactivity of n-paraffins is chain length dependent, increasing with the molecular weight. Detailed characterization by NMR and GC showed that branching groups abundance in the middle distillate products was the following: methyl ? ethyl > propyl.Emission tests carried out with FT diesel and commercial ultra low sulfur diesel showed that FT diesel has excellent combustion properties and leads to a reduction of emissions. 相似文献
54.
The definition of suitable case-base maintenance policies is widely recognized as a major key to success for case-based systems; underestimating this issue may lead to systems that either do not fulfill their role of knowledge management and preservation or that do not perform adequately under performance dimensions, namely, computation time and competence and quality of solutions. The goal of this article is to analyze some automatic case-base management strategies in the context of a multimodal architecture combining case-based reasoning and model-based reasoning. We propose and compare two different methodologies, the first one, called replace , is a competence-based strategy aimed at replacing a set of stored cases with the current one, if the latter exhibits an estimated competence comparable with the estimated competence of the considered set of stored cases. The second one, called learning by failure with forgetting (LFF), is based on incremental learning of cases interleaved with off-line processes of forgetting (deleting) cases whose usage does not fulfill specific utility conditions. Results from an extensive experimental analysis in an industrial plant diagnosis domain are reported, showing the usefulness of both strategies with respect to the maintenance of suitable performance levels for the target system. 相似文献
55.
We study the best OSPF style routing problem in telecommunication networks, where weight management is employed to get a routing configuration with the
minimum oblivious ratio. We consider polyhedral demand uncertainty: the set of traffic matrices is a polyhedron defined by a set of linear constraints, and a routing is
sought with a fair performance for any feasible traffic matrix in the polyhedron. The problem accurately reflects real world networks, where
demands can only be estimated, and models one of the main traffic forwarding technologies, Open Shortest Path First (OSPF)
routing with equal load sharing. This is an NP-hard problem as it generalizes the problem with a fixed demand matrix, which
is also NP-hard. 相似文献
56.
Ilaria Adamo Valeria Diella Alessandro Pavese Pietro Vignola Fernando Francescon 《Journal of the European Ceramic Society》2013,33(15-16):3387-3395
The system Na-feldspar (F) and kaolinite (K) was investigated at temperatures of interest in ceramic applications (1200–1280 °C) to study the effects of F/K ratios by weight and crystallinity degree of kaolinite on the final product, micro-structural features and mullite-glass Gibbs energy of formation (ΔGeff). Mullite and glass are the dominant phases; in general, the higher the temperature, the larger the former. An F/K increase promotes the formation of glass and secondary mullite, appearing along with the primary one. ΔGeff was modelled by α(T) × (F/K)2 + β(T) × F/K + γ(T), α, β and γ being linear functions of temperature whose coefficients were determined by fitting the ΔGeff-theoretical to the ΔGeff-obtained from the measured phase compositions. ΔGeff is less affected by temperature than by F/K, whose increase shifts equilibrium towards glass phases. The ΔGeff-curves for ordered and disordered kaolinite intersect one another at F/K ~0.5, a ratio close to that used in industrial practice. 相似文献
57.
Pietro Altimari Erasmo Mancusi Lucia Russo Silvestro Crescitelli 《American Institute of Chemical Engineers》2012,58(3):899-913
Networks of N identical catalytic reactors with periodically switched inlet and outlet sections are studied for first‐order irreversible exothermic reactions. Switching strategies with inlet and outlet sections periodically jumping a fixed number ns of reactors are considered and the mechanisms governing the formation of traveling temperature wave‐trains are analyzed as ns and N are varied. To this aim, a geometric approach to the analysis of the network energy balance is developed. Based on this approach, infinite domains of traveling temperature wave‐trains are predicted for any ns and N. Analytical approximations are derived for the stability limits and the spatiotemporal patterns of these regimes. Stability boundaries predicted analytically include for any solution the largest part of the stability region computed by numerical simulation. Moreover, good agreement is found between the structure of the spatiotemporal patterns computed numerically and that predicted based on the proposed approach. © 2011 American Institute of Chemical Engineers AIChE J, 2012 相似文献
58.
Circuit ageing degradation is becoming worse in advanced technologies, while application fields like military, medical and energy demand more reliability. Thus, reliability is one of the most important challenges of the semiconductor industry [1]. In this work, we review the physical ageing phenomena, their simulation model, and how they can be avoided. Then, we propose a synthesis methodology composed of classical circuit optimization with the reliability analysis in earlier stages. Also, the variability of the integration process technology is taken into account. We compare a classical and a reliable designed digital controlled oscillator (DCO) in order to show a reduction of 16% in the oscillation frequency ageing degradation. In this way, the reliable design makes the circuit lifetime five times longer, if we fix the maximum frequency ageing degradation at 2.0%. Finally, we present the reliability as a design criterion, advantages and disadvantages of our methodology. 相似文献
59.
Mario Gleria Francesco Minto Lucia Flamigni Pietro Bortolus 《Journal of Inorganic and Organometallic Polymers》1992,2(3):329-344
The synthesis and photochemical behavior both in solution and in the solid state of poly[bis(4-isopropylphenoxy)0.8 (4-benzoylphenoxy)1.2 phosphazene] is described. The main reaction of this material under illumination with light of a wavelength longer than 340 nm is the intramolecular abstraction of an hydrogen atom by the excited benzophenone substituent from the 4-isopropylphenoxy moiety geminally substituted on the same phosphorus of the phosphazene chain. In this way highly reactive radical species are produced which induce very efficient photo-cross-linking of the phosphazene copolymer and insolubilization. The efficiency of this process in the solid state is examined in view of the potential application of this material as a polyphosphazene-based negative photoresist. 相似文献
60.
D'Arco G Blasi F Cossignani L Di Giacomo F Ciavardelli D Ventura F Scipioni S Simonetti MS Damiani P 《Journal of the science of food and agriculture》2012,92(4):952-959
BACKGROUND: Rabbit meat has excellent nutritive properties. The purpose of this study was to characterize rabbit meat and offal; in particular, the lipid fraction was studied in order to evaluate total and positional fatty acid (FA) compositions of triacylglycerol (TAG) and phosphatidylcholine (PC) fractions. Eight samples of weaned and eight of fattened rabbits were considered. RESULTS: Fattened rabbit meat contained slightly higher protein percentage content (P < 0.05) in comparison to weaned (20.1% versus 18.0%). Calcium content was higher in meat than in offal, unlike sodium, iron, zinc, manganese and copper. The cholesterol content in offal was much higher than in meat. FA profiles of total lipid showed a high percentage of unsaturated fatty acids and an n‐6/n‐3 ratio of 10.3 for fattened rabbit meat. Stereospecific analysis of TAG and PC was carried out on an eight‐sample pool of each meat and offal from weaned and fattened rabbits. In all samples the sn‐2‐position was prevalently esterified with oleic and linoleic acids in TAG, with polyunsaturated fatty acids in PC. CONCLUSION: Lipids from rabbit meat presented higher content of monounsaturated FA and lower n‐6/n‐3 ratio in comparison to offal, which was characterized by higher cholesterol and mineral levels. Copyright © 2011 Society of Chemical Industry 相似文献