The paper addresses the problem of constrained pole placement in discrete-time linear systems. The design conditions are outlined in terms of linear matrix inequalities for the Dstable ellipse region in the complex Z plain. In addition, it is demonstrated that the D-stable circle region formulation is the special case of by this way formulated and solved pole placement problem. The proposed principle is enhanced for discrete-lime linear systems with polytopic uncertainties.
The paper presents kinematic characteristics of the double 4-link coupler system, used in actual powertrain of low-floor trams (NGT6-Kr). The spatial kinematic model of the couplings was formulated assuming ideal joints and rigid members. The constraints equations of the mechanism were solved iteratively and differentiated to obtain the Jacobian matrix. The mobility and singularity analysis of the coupler mechanism was performed on the basis of the Jacobian matrix. Kinematic characteristics of the single and double coupler system were analyzed for gross angular and linear axle displacements (misalignments), taking the advantage of the fully nonlinear model. The coupling system was evaluated based on criteria describing homokinetics, balancing and clearance demands, and angular displacements in the joints. These criteria were determined for different design parameters like: coupler proportions, platform shift and angle, middle shaft length.
The article is a follow-up and an extension to previously published papers by HolzerŻelażewska & Holzer (1997) and Holzer-Żelażewska & Tymicki (2009). Fristly, we have added new cohorts to the cohort analysis based on the individual data from births registration for the years 2009–2015. Secondly, we have extended the scope of the study by taking into account the context of postponement and recuperation to analyses of cohort fertility of Polish women. The approach applied to the fertility postponement and recuperation on the cohort data refers to the method which was originally proposed by Frejka (2011) and Lesthaeghe (2001) and further developed by Sobotka et al. (Sobotka et al., 2011). This method allows for calculation of fertility postponement and recuperation measures with respect to a benchmark cohort chosen as the one that first experiences an onset of the increase in the mean age of motherhood at first birth. The results show the remarkable changes in the fertility patterns in Poland. The main driving forces behind the change in fertility patterns in Poland are related to the postponement of first births along with a relatively good recuperation. The magnitude of recuperation for Polish cohorts dropped significantly for second births and was almost non-existent for third and higher births. Therefore, the pattern of fertility in Poland observed till 2015 could be characterized by postponement and recuperation of first births along with a significant decrease in second births with perpetual postponement of third and higher births.
Both sarcoidosis and primary Sjögren syndrome (pSS) are multisystem disorders of unknown etiology, which share certain clinical features, making the diff erential diagnosis a real challenge in clinical practice. Several published case reports and case series have posed the question as to whether there is a real association — mimicry between the two diseases or it is just coincidence. We attempt, aft er systematic and comprehensive research of the relevant published literature, to present all those data, clinical or paraclinical, which could be useful in the diagnostic approach and the distinguishment of the two diseases. It is certain that, besides the classic diagnostic methods, emerging is the role of immunology and genetics on this direction, although not established yet.