Properties of thermomechanically rolled Nb/Ti microalloyed steel sheets

Structure and mechanical properties of a Nb/Ti microalloyed steel, thermomechanically rolled on a strip-production facility, are evaluated. Small (0.02%) titanium addition to niobium-containing steel is found to increase precipitation while reducing grain-refining potential of niobium. This effect increases with increasing finish-rolling temperature, and is also reflected in an increased charpy energy transition temperature. A reduced tendency for precipitation in a nitrogen-free austenite together with the short interpass times in the finishing train, is assumed to reduce the tendency for pancaking, which is prerequisite for an effective grain refining.     

RASP—A language with operations on fuzzy set

At the Center for Multidisciplinary Studies, University of Belgrade, Yugoslavia, a high level language for easily manipulating fuzzy set operations was developed. In this paper, after a brief introduction to the theory of fuzzy sets, some features and possibilities are described from the user point of view, and an application in picture enhancement is shown. The language presented was written in BASIC, thus any microcomputer, for personal/home use, should be able to execute RASP.     

A distributed and adaptive signal processing approach to exploiting correlation in sensor networks

We propose a novel approach to reducing energy consumption in sensor networks using a distributed adaptive signal processing framework and efficient algorithm.¹ While the topic of energy-aware routing to alleviate energy consumption in sensor networks has received attention recently [C. Toh, IEEE Commun. Mag. June (2001) 138; R. Shah, J. Rabaey, Proc. IEEE WCNC, March 2002], in this paper, we propose an orthogonal approach to complement previous methods. Specifically, we propose a distributed way of continuously exploiting existing correlations in sensor data based on adaptive signal processing and distributed source coding principles. Our approach enables sensor nodes to blindly compress their readings with respect to one another without the need for explicit and energy-expensive inter-sensor communication to effect this compression. Furthermore, the distributed algorithm used by each sensor node is extremely low in complexity and easy to implement (i.e., one modulo operation), while an adaptive filtering framework is used at the data gathering unit to continuously learn the relevant correlation structures in the sensor data. Applying the algorithm to testbed data resulted in energy savings of 10–65% for a multitude of sensor modalities.     

A numerical study of a utility boiler tangentially-fired furnace under different operating conditions

For prediction of complex processes in two-phase turbulent reactive flows within large-scale boiler furnaces firing pulverized coal, a comprehensive 3D differential mathematical model and CFD computer code have been developed in-house. The model incorporates trade-offs between submodels sophistication and computational practicality. An easy-to-use interface for introducing input data and grid generation has been build within the code. The main purpose of the paper is to present numerical predictions of processes in the case-study furnace under different operating conditions, obtained by the developed model. The paper also provides information on characteristics and evaluation of the model, with a grid refinement study and comparisons with comprehensive data. The effects of different operating conditions on the processes in the case-study furnace are correctly predicted, demonstrating the ability of the developed model to perform parametric studies.     

Model checking: recent improvements and applications

Model checking (Baier and Katoen in Principles of model checking, MIT Press, Cambridge, 2008; Clarke et al. in Model checking, MIT Press, Cambridge, 2001) is an automatic technique to formally verify that a given specification of a concurrent system meets given functional properties. Its use has been demonstrated many times over the years. Key characteristics that make the method so appealing are its level of automaticity, its ability to determine the absence of errors in the system (contrary to testing techniques) and the fact that it produces counter-examples when errors are detected, that clearly demonstrate not only that an error is present, but also how the error can be produced. The main drawback of model checking is its limited scalability, and for this reason, research on reducing the computational effort has received much attention over the last decades. Besides the verification of qualitative functional properties, the model checking technique can also be applied for other types of analyses, such as planning and the verification of quantitative properties. We briefly discuss several contributions in the model checking field that address both its scalability and its applicability to perform planning and quantitative analysis. In particular, we introduce six papers selected from the 23rd International SPIN Symposium on Model Checking Software (SPIN 2016).

     

Output‐based H2 optimal controllers for a class of discrete‐time stochastic linear systems with periodic coefficients

The aim of the paper is to present a design procedure of the optimal controller minimizing the H₂‐type norm of discrete‐time stochastic linear systems with periodic coefficients simultaneously affected by a nonhomogeneous but periodic Markov chain and state and control multiplicative white noise perturbations. Firstly, two H₂‐type norms for the linear stochastic systems under consideration were introduced. These H₂‐type norms may be viewed as measures of the effect of the additive white noise perturbations on the regulated output of the considered system. Before deriving of the state space representation of the optimal controller, some useful formulae of the two H₂‐type norms were obtained. These formulae are expressed in terms of periodic solutions of some suitable linear equations and are derived in the absence of some additional assumptions regarding the Markov chain other than the periodicity of the sequence of the transition probability matrices. Further, it is shown that the optimal H₂ controller depends on the stabilizing solutions of some specific systems of coupled Riccati equations, which generalize the well‐known control and filtering equations from linear time invariant case. For the readers convenience, the paper presents iterative numerical algorithms for the computations of the stabilizing solutions of these Riccati type systems. The theoretical developments are illustrated by numerical examples. Copyright © 2014 John Wiley & Sons, Ltd.     

Modelling effects of S3D visual discomfort in human emotional state using data mining techniques

Multimedia Tools and Applications - In recent years, the rapid development of diverse media has been evident in disparate fields such as consumer electronics, automotive infotainment and healthcare...     

Frequency and time domain comparison of selective polynomial filters with corrected phase characteristics

Two solutions to the polynomial filter’s transfer function synthesis problem are considered for comparison in the frequency and time domain: the broad class of filters with a critical monotonic amplitude characteristic (CMAC) in the passband and filters which use Chebyshev (C) polynomials. To complete the synthesis procedure for linear phase applications, group delay correctors are considered, for which a convenient approximation procedure is proposed here. Comparisons of the original functions and the corrected ones are performed in the frequency and time domain. It is shown that when CMAC and C are compared as such, the latter is by no means preferable from the selectivity point of view, while the opposite stands when the comparison is based on passband amplitude distortions. When phase-corrected filtering functions are compared, based on circuit complexity and time domain performance, the CMAC are shown to be preferable.     

Assessing and Modelling the Influence of Household Characteristics on Per Capita Water Consumption

Sustainable urban water supply management requires, ideally, accurate evidence based estimations on per capita consumption and a good understanding of the factors influencing the consumption. The information can then be used to achieve improved water demand forecasts. Water consumption patterns in the developed countries have been extensively investigated. However, very little is known for the developing world. This paper investigates per capita water consumption resulting from water use activities in different types of households typically found in urban areas of the developing world. A data collection programme was executed for 407 households to extract information on household characteristics, water user behaviour and intensity and the nature of indoor and outdoor water use activities. The rigorous statistical analysis of the data shows that per capita water consumption increases with income: 241, 272 and 290 l/capita/day for low, medium and high income households, respectively. Additionally, the results suggest that per capita consumption increases with the number of adult female members in the household and almost one-third of consumption is via taps. The collected data has been used to develop statistical models using two different regression techniques: multiple linear (STEPWISE) and evolutionary polynomial regression (EPR). The inclusion of demographic parameters in the developed models considerably improved the prediction accuracy. Two of the best performing models are used to forecast the water demand for the city, using four future scenarios: market forces, fortress world, policy reform and great transition. The results suggest that the domestic water demand would be highest in the fortress world scenario due to the increase in population and size of built-up area.     

Antioxidant activity of strawberry (Fragaria × ananassa Duch.) leaves

Antioxidant activity of aqueous extracts from two cultivated strawberry leaves, Senga Sengana and Mount Everest, obtained by maceration, reflux extraction and ultrasonic extraction, was investigated. Antioxidant activity of extracts was assessed by DPPH, FRAP, FIC and H₂O₂ test; total phenolics and flavonoids were assessed by Folin–Ciocalteu and aluminium chloride methods, respectively. Extract obtained from Senga Sengana by reflux extraction, containing higher amounts of extractive matter, total phenolics and flavonoids, has shown higher antioxidant activity (EC_50(DPPH) = 10.4 μg/mL; FRAP = 258.61 mgFe²⁺/g dry extract.; FIC activity = 62.6% in concentration of 2 mg/mL; H₂O₂ scavenging = 25.43% in concentration of 0.5 mg/mL) compared to extracts obtained by other extraction techniques. Rutin, coumaroyl-galloyl-glucopyranoside, hydroxyphenylethyl-coumaroyl-glucopyranoside, derivates of hydroxyphenylethyl-coumaroyl-glucopyranoside, chlorogenic acid and p-coumaroylhexose have been identified by UHPLC–DAD–HESI–MS analysis.