Association Rule Mining for Continuous Attributes using Genetic Network Programming

Most of the existing association rule mining algorithms are able to extract knowledge from databases with attributes of binary values. However, in real‐world applications, databases are usually composed of continuous values such as height, length or weight. If the attributes are continuous, the algorithms are commonly integrated with a discretization method that transforms them into discrete attributes. Discretization is a process of transforming a continuous attribute value into a finite number of intervals and assigning each interval into a discrete numerical value. However, the user most often must specify the number of intervals, or provide some heuristic rules to be used while discretization, and then it is difficult to get the highest attribute interdependency and at the same time get the lowest number of intervals. In this paper we present an association rule mining algorithm that is suited for continuous valued attributes commonly found in scientific and statistical databases. We propose a method using a new graph‐based evolutionary algorithm named ‘genetic network programming (GNP)’ that can deal with continuous values directly, that is, without using any discretization method as a preprocessing step. GNP represents its individuals using graph structures and evolves them in order to find a solution; this feature contributes to creating very compact programs and implicitly memorizing past action sequences. In the proposed method using GNP, the significance of the extracted association rules is measured by the use of χ² test, and only important association rules are stored in a pool all together through generations. Results of experiments conducted on a real‐life database suggest that the proposed method provides an effective technique for handling continuous attributes. Copyright © 2008 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Nitrogen solubility in CaO-SiO2, CaO-MgO-SiO2, and BaO-MgO-SiO2 melts

Nitrogen solubility in molten CaO-SiO₂, CaO-MgO-SiO₂, and BaO-MgO-SiO₂ silicate systems was measured as functions of nitrogen and oxygen partial pressures and composition at 1823 K. Experimental findings indicate that nitrogen exists as a free nitride ion or is associated with silicate networks, depending principally on the slag composition. A special analytical technique was developed to separately determine the two species. Its dissolution mechanism, which is similar to that for hydrogen, was proposed, being supported by the detection of a Si-N bond by infrared spectroscopy. Neither the content of free nor incorporated nitrogen was demonstrated to have a very good correlation with the CaO or SiO₂ activity in the melts, probably because the activity coefficient of nitrogen is affected by the slag composition. Formerly Graduate Student, Department of Metallurgy, The University of Tokyo.     

Plant photosensitizers: A survey of their occurrence in arid and semiarid plants from North America

Various plants native to arid and semiarid habitats throughout the southwestern United States, Baja California, and northern Mexico were bioassayed for phototoxic natural products. Approximately 115 species representing 57 genera and eight plant families were assayed for phototoxic activity by standard antimicrobial techniques usingEscherichia coli andSaccharomyces cerevisiae. Phototoxic constituents were extracted from numerous members in the Asteraceae (Compositae) and occurred with highest frequency among species of the subtribe Pectidinae (tribe Heliantheae). Extracts ofPectis, the largest genus in the Pectidinae, had substantial light-activated biocidal action despite the paucity of acetylenic thiophenes, the phototoxins characteristic of most other genera in the subtribe. Leaf resin from the creosote bush [Larrea tridentata (Sesse & Mol. ex DC.) Coville; Zygophyllaceae], a dominant desert shrub, possessed potent antimicrobial activity in the absence of light; however, the toxicity of this extract was slightly enhanced in the presence of UVA irradiation. Phototoxic antimicrobials were not detected in extracts of selected species from the Asclepiadaceae, Chenopodiaceae, Hydrophyllaceae, Lamiaceae, Polygonaceae, or Solanaceae.     

Biohydrogen Production via Dark Fermentation with Pig Manure and Glucose Using pH-Dependent Feeding

Process controls for mesophilic dark fermentation using a pH-dependent feeding strategy without NaOH addition were examined. One reactor utilizing microorganism holdback and two continuously stirred-tank reactors (CSTRs) with the same volume were employed. These were fed with pig manure and glucose as cosubstrates. Different hydraulic retention times were applied. The target pH was 5.5 within a limited range and controlled by varying organic loading rate. When the pH target interval was exceeded, the hydrogen production rate (HPR) decreased, and CH₄ was produced. A pH below the target interval had positive effects on the HPR.     

Durability and chromatic behavior in cement pastes containing ceramic industry milling and glazing by-products

The decay in mortar and concrete induced by extremely aggressive agents is normally the result of the agent-binder reaction. Cement composition and characteristics therefore determine the durability of the mortars and concretes of which they form part. The existing legislation envisages the use of different types of additions in cement, which have a direct effect on the durability of elements in buildings and civil works. This study addressed the inclusion of ceramic industry milling and glazing sludge as an active addition in cement. The reuse of this industrial waste is consistent with environmental policies that seek to reduce or eliminate spoil heaps by recycling industrial waste and byproducts as raw materials, in keeping with circular economy principles. The research conducted makes an innovative contribution to the valorization of this waste, and highlights the resistance of blended cement pastes to chemical agents, further to the Koch-Steinegger method. Water-induced decay in freeze/thaw situations was also studied. The processes involved were identified by analyzing the mineralogical variations detected with X-ray diffraction, the morphological alterations observed with scanning electron microscopy and the mercury porosimetric findings on pore size distribution. The suitability of these binders for aesthetically demanding applications was also explored by measuring the color in pastes exposed to aggressive chemical agents. For the first time, a correlation was established between color parameters and the formation of the reaction products generated during chemical attack.     

Vertical and horizontal integration systems in Industry 4.0

Wireless Networks - Industrial and technological growth, sponsored by the new organizational systems generated by the fourth industrial revolution, require adapt new business management ways in the...     

Photocatalytic cyclohexane oxidehydrogenation on sulphated MoOx/γ-Al2O3 catalysts

The photocatalytic oxidative dehydrogenation of cyclohexane on sulphated MoO_x/γ-Al₂O₃ catalysts has been studied in a two-dimensional fluidized bed photoreactor. The influence of Mo loading at similar sulphate content and the effect of catalyst preparation method have been investigated.Considering the influence of Mo loading at similar sulphate content, the highest photoactivity at 2.4 SO₄ wt% was found at MoO₃ loading of 8 wt%. Selectivity to cyclohexene was 100%, irrespective of the Mo content.At fixed MoO_x content, in particular at 50% of theoretical monolayer coverage, the preparation method of catalysts strongly affected the photocatalysts performances, showing in addition a slight decrease in selectivity to cyclohexene due to side-production of benzene. All the catalysts showed a similar equivalent band gap energy. Thermogravimetric analysis evidenced the presence of surface sulphate species of different thermal stabilities. A linear correlation of photoactivity with the surface sulphates amount of lower thermal stability has been found for all sub-monolayer MoO_x sulphated catalysts. The neighboring of surface sulphates to octahedral polymolybdate species appears to be a key parameter for the photoactivity of the catalysts.The catalyst selectivity was related to surface acidity. Higher acidity resulted in increased cyclohexene dark adsorption and consequently in enhanced benzene formation.     

Borehole stability analysis considering spatial variability and poroelastoplasticity

Typically, stability analysis of oil-producing wells is carried out considering that both the hydraulic and mechanical parameters of the rock mass are deterministic. When analyzing borehole stability, two failure mechanisms are generally considered, namely, failure due to either tensile or compressive (shear) stresses. These mechanisms are produced, respectively, by either too high or too low drilling fluid pressure. Mechanical and hydraulic properties of rock masses, and in particular sedimentary rock masses, may show a considerable degree of spatial variability. This paper focuses on the evaluation of the limits for the internal pressure associated with a target probability of failure, taking into account both the spatial variability of hydraulic and mechanical properties, and the simple variability of the initial pore pressure and in-situ stresses. The analysis is performed with a finite element program that incorporates coupled fluid-mechanical effects and elastoplastic behavior of the rock. In this way, the proposed borehole stability analysis can be set into a reliability-based framework described in the paper. Examples are shown, using stochastic data from the literature, and conclusions are drawn regarding the effect of spatial variability on the borehole stability.     

Characterization of phenolics by LC-UV/vis, LC-MS/MS and sugars by GC in Melicoccus bijugatus Jacq. 'Montgomery' fruits

Fruits of the native South American tree Melicoccus bijugatus Jacq. (Sapindaceae) are consumed for both dietary and medicinal purposes, but limited information is available about the phytochemistry and health value of M. bijugatus fruits. Fruit tissues of the Florida Montgomery cultivar were assessed for sugars, using gas chromatography, and for total phenolics, using UV spectroscopy. Reverse phase high performance liquid chromatography (HPLC) fingerprints of crude methanolic pulp, embryo and seed coat extracts were obtained at 280 nm. Phenolics were characterised by both HPLC UV/vis analysis and HPLC electrospray ionization tandem mass spectrometry. Major sugars detected in the pulp and embryo extracts were sucrose, followed by glucose and fructose. The glucose:fructose ratio was 1:1 in the pulp and 0.1:1 in the embryo. Total phenolic concentrations of the fruit tissues were in the order: seed coat > embryo > pulp. Phenolic acids were identified mostly in pulp tissues. Phenolic acids, flavonoids, procyanidins and catechins were identified in embryo tissues, and higher molecular weight procyanidins were identified in seed coat tissues. This study provides new information about the phytochemistry and the potential health value of the Montgomery cultivar M. bijugatus fruit tissues.     

Experimental verification of various methods for biological hydrogen production

The aim of the work was to compare two different biological methods for hydrogen production: fermentative and photosynthetic based upon the modality of batch cultures. For testing of fermentative bio-hydrogen production four mixed cultures representing anaerobic microorganisms (dominant strain Clostridium) were selected. The kinetic parameters on the intensity of bio-hydrogen production were established. The efficiency coefficient of transformation ranged from 1.65 mol H₂/mol glucose in the pectin culture up to 2.45 in the mixed culture. The bio-hydrogen concentration never exceeded 30%. The carbon dioxide was produced in a ratio of CO₂ to H₂ (0.5–0.67)/1. The testing of green algae proved that the most effective was the algae species Scenedesmus. High bio-hydrogen purity was analytically verified. The fermentative method of H₂ production is more efficient; it does not need light, has a longer efficiency of one charge and enables effective use of different biological wastes.