A supervisory observer is a multiple-model architecture, which estimates the parameters and the states of nonlinear systems. It consists of a bank of state observers, where each observer is designed for some nominal parameter values sampled in a known parameter set. A selection criterion is used to select a single observer at each time instant, which provides its state estimate and parameter value. The sampling of the parameter set plays a crucial role in this approach. Existing works require a sufficiently large number of parameter samples, but no explicit lower bound on this number is provided. The aim of this work is to overcome this limitation by sampling the parameter set automatically using an iterative global optimisation method, called DIviding RECTangles (DIRECT). Using this sampling policy, we start with 1 + 2np parameter samples where np is the dimension of the parameter set. Then, the algorithm iteratively adds samples to improve its estimation accuracy. Convergence guarantees are provided under the same assumptions as in previous works, which include a persistency of excitation condition. The efficacy of the supervisory observer with the DIRECT sampling policy is illustrated on a model of neural populations.

AbstractThis paper explores the accidents that occurred in the railway system of Serbian Railways from 2006 to 2012. The total number of the sample observed includes 3983 accidents, of which 2725 or 68.41% were caused by the human factor. One of the major contemporary problems – global climate change and the increase of average temperatures – has not yet been considered in the context of external factors for increasing the risk of accidents. The air pressure has become accepted as an external factor, in addition to the air temperature. It is assumed that temperature and air pressure have a significant impact on the risk of railway accidents occurrence (taking only accidents caused by a human factor into account). This assumption was made based on reduced cognitive abilities of railway staff as a result of extreme differences in temperature and air pressure. In this paper, the emphasis is put on Railway Crossings (RC) as sites where two forms of traffic intersect, since it is noticed that certain weather c...

Mechanical milling of commercial ZnO and SnO2 was used to produce a ZnO/SnO2 composite with a high density of surface defects; in particular, zinc interstitials (Zni) and oxygen vacancies (VO). To determine the impact of surface defects on photocatalytic activity, the relative concentration ratio of bulk defects to surface defects was modified by annealing at 400 and 700 °C. The possible application of the ZnO/SnO2 composite as a natural sunlight and UV-light driven photocatalyst was revealed via de-colorization of methylene blue. In both cases the ZnO/SnO2 composite exhibited enhanced photocatalytic activity as compared to the pristine ZnO. In order to investigate the origin of the enhancement, the pristine metal oxides and composites were characterized using a variety of techniques, including X-ray diffraction (XRD), Raman and Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), laser diffraction particle size analysis, Brunauer–Emmett–Teller, UV-Vis diffuse reflectance and photoluminescence spectroscopy. High-resolution transmission electron microscopy (HRTEM) and elemental mapping analyses were used to reveal the presence of SnO2 nanocrystallites on the surface of larger ZnO particles. The enhanced photocatalytic activity of the composite can be attributed to the synergetic effect of the surface defects and the ZnO/SnO2 heterojunction particles, which facilitated charge separation, thereby hindering the recombination of photogenerated carriers. This study draws attention to mechanical activation as an inexpensive and environmentally friendly technique for the large-scale production of the composite with an enhanced photocatalytic activity under illumination of either UV or sunlight.

Original scientific paper The paper presents analysis of the influence of cutting parameters on surface roughness during CO2 laser cutting process of tungsten alloy by using nitrogen as assist gas, based on control charts made by statistical process control (SPC) approach. Dependent variable is surface roughness, while independent variables are laser power and cutting speed. The control chart used within this paper is a variation of the moving means chart of experimental data samples, that calculates mean and range values using the three consecutive individual values. Applying the criteria often used in the SPC methods for the assessment of "out of control" situations, it may be inferred that increasing the cutting speed leads to worsening of control status for the process with lower laser power used.

Total phenolic (TPC), flavonoid (TFC) and tannin (TTC) contents, total SO2, total acids, pH, and reducing sugars were measured in twenty five Slovenian red wines from three key wine producing regions, Podravje, Posavje and Primorska. The results were chemometrically analysed and the wines were classified according to wine growing region and vine variety. Principal component analysis proved that TPC, TFC and TTC contents were primarily responsible for variation in the wines. Additionally, linear discriminant analysis (LDA) was performed and resulted in the satisfactory classification of samples by both vine variety and region.

The institutes of contemporary family law are rooted in Roman law, including the property relations of marital partners. From the historical perspective, the property-legal relations of marital partners in Bosnia and Herzegovina (BiH) were subject to religious regulations and the rules of the General Civil Code and Family Law of the Socialist Republic of Bosnia and Herzegovina. The article analyzes the solutions applied during the Roman, the Ottoman, and the AustroHungarian rule as well as the solutions included in the currently valid Basic Law on Marriage and Family Laws in BiH. The authors focus on the development of family law in terms of property relations of marital partners and provide historical-legal overview of the development of family law from the absolute power of pater familias to the full equality of marital partners.

Article history: Received 8 June 2017 Received in revised form 27 July 2017 Accepted 29 July 2017 The purpose of the paper was to show an idea how numerical simulations of flow around a stationary irregularly shaped body can be used to estimate instability of the body during a real-world motion of such a body (e.g. a metal fragment). To the best of our knowledge, there is no evidence that such an analysis is available in literature for irregularly shaped bodies. The novelty is in the introduced method for the stability analysis and the fact that a realworld fragment shape was digitized and used for the analysis. However, the disadvantage is in necessity that real fragments need to be scanned and digitized for the analysis, but the future work should give improvements in this direction. The focus was on the rotational part of the motion, particularly on obtaining the period of the motion when the body rotates, but the solving for angles of rotation was not the objective. We showed an idea on how to estimate the period of instability when continuous rotation occurs after the initial projection of the fragment. We assumed that relatively high angular velocity occurs at the initial condition (initial projection of the fragment), which provided an opportunity to assume further that the axis of rotation remains unchanged during the motion. By analyzing the kinetic energy of rotation, we estimated the period of body rotation until it reached a stable orientation during the high velocity motion. To employ this approach that uses the mechanical energy, it was necessary to obtain the work done by the (aerodynamic) moments of resistance forces about the center of mass. These resistance (aerodynamic) moments were obtained for various orientations of the body using simulations of fluid flow around the real geometry of the body, which was obtained by scanning a real-world fragment, digitizing it, and importing it in a CAD software, which provided the inertial properties through moments of inertia. At each rotation, the kinetic energy of rotation is dissipated through work of the aerodynamic moment which was the basis for calculation when the body takes a steady orientation for the rest of the motion.