Distributed measurement systems

In this paper the technologies that permit the development of distributed measurement systems over the internet are discussed. The different concepts of virtual instrumentation are summarized. Two different approaches to measurement system development are compared — the first is based on the commercially available environment , and the second, widely used in the research field, is based on the object-oriented programming.     

Observing the state with componentwise exponentially decaying error

The componentwise exponential asymptotically stable (CWEAS) observer is defined. Its estimation error is componentwise and absolutely bounded by prespecified decaying exponentials. Using the notion of CWEAS introduced earlier, an existence condition for such an observer is proved. Via eigenvalues location and convexity of certain functions one states the maximization problem of the damping factor of the above exponentials and introduces and characterizes the CWEAS detectability. This is an explicit property of the observability pair (A, C), which, under a certain condition involving the pair (B, D), suffices for strong^* detectability and therefore for the existence of a strong observer.     

Studies concerning the course of some acute respiratory diseases in nine districts of south-east area of Romania between November 1994 and April 1995. Epidemiological, virological and serological data

A moderate level of morbidity through acute respiratory diseases (ARD), of the upper tract, viral pneumonia and clinical influenza was recorded during November 1994 and April 1995 in the South-East area of Romania (nine districts). By virological and serological investigation adenosyncytial respiratory, parainfluenza type 3 and influenza type B viruses were found to be the most frequent etiological agents of these infections which affected especially the babies and the children of 1-14 years of age. Sporadic influenza outbreaks were noticed from which influenza strains of virus were isolated, antigenically related to the prototype strain A/Johannesburg 33/94.     

The analytical calculation of journal bearing parameters by means of the finite bearing theory

The present paper proposes an original analytical solution of the thermohydrodynamic lubrication and the validation of the model for journal bearings. The validation consists of comparing the hydrodynamic parameters calculated by means of numerical methods with those calculated analytically for the same journal bearing. Besides providing a higher simplicity of calculations in comparison with numerical methods, the new mathematical model ensures a very good precision for journal bearings having finite dimensions. Copyright © 2011 John Wiley & Sons, Ltd.     

A decentralized approach for convention emergence in multi-agent systems

The field of convention emergence studies how agents involved in repeated coordination games can reach consensus through only local interactions. The literature on this topic is vast and is motivated by human societies, mainly addressing coordination problems between human agents, such as who gets to redial after a dropped telephone call. In contrast, real-world engineering problems, such as coordination in wireless sensor networks, involve agents with limited resources and knowledge and thus pose certain restrictions on the complexity of the coordination mechanisms. Due to these restrictions, strategies proposed for human coordination may not be suitable for engineering applications and need to be further explored in the context of real-world application domains. In this article we take the role of designers of large decentralized multi-agent systems. We investigate the factors that speed up the convergence process of agents arranged in different static and dynamic topologies and under different interaction models, typical for engineering applications. We also study coordination problems both under partial observability and in the presence of faults (or noise). The main contributions of this article are that we propose an approach for emergent coordination, motivated by highly constrained devices, such as wireless nodes and swarm bots, in the absence of a central entity and perform extensive theoretical and empirical studies. Our approach is called Win-Stay Lose-probabilistic-Shift, generalizing two well-known strategies in game theory that have been applied in other domains. We demonstrate that our approach performs well in different settings under limited information and imposes minimal system requirements, due to its simplicity. Moreover, our technique outperforms state-of-the-art coordination mechanisms, guarantees full convergence in any topology and has the property that all convention states are absorbing.     

Bio‐Based,Self‐Condensed Polyols

A new method for the synthesis of high‐molar‐mass (MM), bio‐based polyols for elastic polyurethanes is developed. This process is based on the self‐condensation of low MM polyols (M_n ≈ 1000) and vacuum removal of the resulting glycerol. Self‐condensation products are hyperbranched estolide polyols with average MMs close to 3000 and hydroxyl numbers in the range of 40–95 mg KOH g^?1. Three polyols, one with primary and two with secondary hydroxyls and different functionalities, are studied. The transesterification proceeded much faster with primary hydroxyls, leading to high‐viscosity products. The effect of functionality and reactivity of starting polyols on properties is discussed. Practical applications: The process is useful for upgrading the existing natural oil‐based polyols to higher MM, lower OH number and variable‐functionality polyols, for expanding application in the urethane field. The process is simple, involving just an oil‐based polyol, a catalyst, and heating under vacuum.     

Insights into the In Vitro Formation of Apatite from Mg-Stabilized Amorphous Calcium Carbonate

A protein-free formation of bone-like apatite from amorphous precursors through ball-milling is reported. Mg²⁺ ions are crucial to achieve full amorphization of CaCO₃. Mg²⁺ incorporation generates defects which strongly retard a recrystallization of ball-milled Mg-doped amorphous calcium carbonate (BM-aMCC), which promotes the growth of osteoblastic and endothelial cells in simulated body fluid and has no effect on endothelial cell gene expression. Ex situ snapshots of the processes revealed the reaction mechanisms. For low Mg contents (<30%) a two phase system consisting of Mg-doped amorphous calcium carbonate (ACC) and calcite “impurities” was formed. For high (>40%) Mg²⁺ contents, BM-aMCC follows a different crystallization path via magnesian calcite and monohydrocalcite to aragonite. While pure ACC crystallizes rapidly to calcite in aqueous media, Mg-doped ACC forms in the presence of phosphate ions bone-like hydroxycarbonate apatite (dahllite), a carbonate apatite with carbonate substitution in both type A (OH⁻) and type B (PO₄³⁻) sites, which grows on calcite “impurities” via heterogeneous nucleation. This process produces an endotoxin-free material and makes BM-aMCC an excellent “ion storage buffer” that promotes cell growth by stimulating cell viability and metabolism with promising applications in the treatment of bone defects and bone degenerative diseases.     

A modified matyas algorithm (MMA) for random process optimization

The adaptive random search (ARS) methods for optimization, owing to successive proposed improvements, present some favourable features such as simple handling of difficult functions and implicit non-linear constraints, and a high reliability in obtaining the global optimum. In order to confer more efficiency and reliability on the optimization solution for multimodal problems, the successive strategies of ARS techniques derived from the basic algorithm of Matyas [Automn remote Control 26, 224 (1965)] were coupled. A number of examples previously solved by means of other ARS methods provide an evaluation of the efficiency of the proposed algorithm. The optimum procedure parameter values and their significance for a favourable choice are discussed.