Minor maintenance actions and their impact on diagnostic and prognostic CBM models

Minor maintenance actions can affect condition-monitoring measurements, which may in turn affect the accuracy of diagnostic and prognostic techniques used in condition-based maintenance (CBM). Outputs of a CBM model include the calculation of optimal maintenance decisions, conditional reliability, and the calculation of remaining useful life, among other measures. It is necessary to have a model for the manner in which the condition monitoring data changes over time to produce these output measures; many models have been developed to do so. It is also common to record minor maintenance actions carried out on critical assets, with lubricant changes being one of the most common, but it is unusual for models to consider the impact of such maintenance actions that affect the condition monitoring data. In this paper we discuss the impact of minor maintenance on CBM models. A dataset on a collection of gearboxes, consisting of reliability and oil analysis information, including data on oil changes and oil additions, is used to illustrate the benefit of modelling minor maintenance actions.     

A new approach for kinetic modeling and optimization of rubber molding

Although extensive research has been carried out on the understanding of the complex vulcanization process, the influence of reversion through exposure time and temperature on the vulcanization degree remains unclear. Therefore, the main aim of this study was a novel optimization approach that can help the industrial practitioners to select the optimal operating parameters, exposure time, and molding temperature, to achieve desired vulcanization degree of selected product. Spheres of four different diameters (2.5, 5, 10, and 20 cm) were selected as test geometry for simulation and optimization of rubber molding. Obtained vulcanization rheometer data for commercially available rubber blend (NR/SBR) were fitted by a new modeling approach, dividing vulcanization curve into two fitting sets: curing and reversion. The heat transfer equations for chosen geometry were coupled with proposed kinetic model. A new temperature-dependent kinetic parameter x, as the maximal reversion degree, was introduced, enabling determination of the lowest operating molding temperature (T_min = 132.36 °C), preventing high reversion and overheating of the rubber product. The final optimization goal was assessment of the optimal temperature and vulcanization time dependence on the rubber products dimensions. Proposed models have precise prediction with R² values greater than 0.8328 and MAPE less than 2.3099%.     

Calculation of the paired Haar transform through shared binary decision diagrams

A concept of paired Haar transform (PHT) for representation and efficient optimization of systems of incompletely Boolean functions has recently been introduced. In this article, a method to calculate PHT for incompletely specified switching functions through shared binary decision diagrams (SBDDs) is presented. The algorithm converts switching functions in the form of SBDDs into their paired Haar spectra and can operate on functions with many variables.     

Fighting Cancer with Bacteria and Their Toxins

Cancer is one of the most important global health problems that continues to demand new treatment strategies. Many bacteria that cause persistent infections play a role in carcinogenesis. However, since bacteria are well studied in terms of molecular mechanisms, they have been proposed as an interesting solution to treat cancer. In this review, we present the use of bacteria, and particularly bacterial toxins, in cancer therapy, highlighting the advantages and limitations of bacterial toxins. Proteomics, as one of the omics disciplines, is essential for the study of bacterial toxins. Advances in proteomics have contributed to better characterization of bacterial toxins, but also to the development of anticancer drugs based on bacterial toxins. In addition, we highlight the current state of knowledge in the rapidly developing field of bacterial extracellular vesicles, with a focus on their recent application as immunotherapeutic agents.     

The asymptotic behavior of the stability radius for a singularly perturbed linear system

In this paper we study the asymptotic behavior of the stability radius of a singularly perturbed system when the small parameter ε tends to zero. It is proved that for such systems the stability radius tends to the min(r₁,r₂), where r₁ is the inverse of the H_∞-norm of the reduced slow model and r₂ is the stability radius of the boundary layer system. © 1998 John Wiley & Sons, Ltd.     

Piezoelectricity and Phase Transitions of the Mixed-Layer Bismuth Titanate Niobate Bi7Ti4NbO21

The piezoelectiric properties of the bismuth titanate niobate Bi₇Ti₄NbO₂₁ have been studied. The two phase transitions at 677° and 856°C are anlayzed based on the measured piezoelectric properties. It is shown that the Bi₇Ti₇NbO₂₁ compound is a ferroelectric until 856°C. Bi₃TiNbO₉ clusters are shown to exist within Bi₇Ti₇NbO₂₁ granis. These clusters may be responsible for the small additional piezoelectric activity of the studied material at temperatures higher than 856°C.     

The investigation of the lower limb geometry using 3D sonography and magnetic resonance

The main aim of this work was to test the developed system of a free hand sonographic probe in the clinical conditions. The measuring system consists of navigation system tracking the position of a linear ultrasound probe and the self-developed software to control the tools and analyse the recorded data. It enables both measurement of geometrical parameters according to the self-designed template and the identification of the three dimensional shape of bone. Moreover the software provides virtual planning of surgery and supports the surgeon to execute the planned scenario in the reality.     

Fusion of Map and Sensor Data in a Modern Car Navigation System

The main tasks of car navigation systems are positioning, routing, and guidance. This paper describes a novel, two-step approach to vehicle positioning founded on the appropriate combination of the in-car sensors, GPS signals, and a digital map. The first step is based on the application of a Kalman filter, which optimally updates the model of car movement based on the in-car odometer and gyroscope measurements, and the GPS signal. The second step further improves the position estimate by dynamically comparing the continuous vehicle trajectory obtained in the first step with the candidate trajectories on a digital map. This is in contrast with standard applications of the digital map where the current position estimate is simply projected on the digital map at every sampling instant.

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New Graph Classes of Bounded Clique-Width

The clique-width of graphs is a major new concept with respect to the efficiency of graph algorithms; it is known that every problem expressible in a certain kind of Monadic Second Order Logic called LinEMSOL(τ_1,L) by Courcelle et al. is linear-time solvable on any graph class with bounded clique-width for which a k-expression for the input graph can be constructed in linear time. The notion of clique-width extends the one of treewidth since bounded treewidth implies bounded clique-width. We give a complete classification of all graph classes defined by forbidden one-vertex extensions of the P₄ (i.e., the path with four vertices a,b,c,d and three edges ab,bc,cd) with respect to bounded clique-width. Our results extend and improve recent structural and complexity results in a systematic way.