From Susa to Anuradhapura : reconstructing aspects of trade and exchange in bitumen-coated ceramic vessels between Iran and Sri Lanka from the third to the ninth centuries AD

In contrast with artefactual studies of long-distance trade and exchange in South Asia during the Prehistoric and Early Historic periods ( Ardika et al. 1993; Gogte 1997; Krishnan and Coningham 1997; Tomber 2000; Gupta et al. 2001; Ford et al. 2005), few scientifically orientated analyses have focused on artefacts from the region's Historic period. During excavations at the ancient city of Anuradhapura, Sri Lanka, a number of buff ware ceramics with a putative organic coating on the interior were recovered ( Coningham 2006). Dated stylistically to between the third and ninth centuries ad, analysis of the coatings using gas chromatography–mass spectrometry (GC–MS) and stable isotope analysis (carbon and deuterium) confirmed that the coatings are bitumen—an organic product associated with petroleum deposits. There are no known bitumen sources in Sri Lanka, and biomarker distributions and isotopic signatures suggest that the majority of the samples appear to have come from a single bitumen source near Susa in Iran. The relationship between the bitumen coatings and the vessels is discussed, and it is suggested that the coatings were used to seal permeable ceramic containers to allow them to transport liquid commodities. This study enhances our knowledge of networks of trade and exchange between Sri Lanka and western Asia during Historic times

Unstable systems database: A new tool for students, teachers and scientists

The contribution presents a starting project of a site focused on unstable systems. It is a web-based database in the bilingual version (ENG/CZ) which can be used as an information database for models of unstable processes. The site contains mathematical models of such systems including their simulation files together with basic information about stability of dynamical systems. The paper outlines motivation for development of this database, presents its basic structure and discusses several models from the site. Areas of prospective usage are also suggested together with possible directions of further development of this project. © Springer International Publishing Switzerland 2013

Control Of Slowly Varying Lpv Systems: An Application To Flight Control

Recent results in parameter-dependent control of linear parameter-varying (LPV) systems are applied to the problem of designing gain-scheduled pitch rate controllers for the F-16 VISTA (Variable-Stability In-Flight Simulator Test Aircraft). These methods, based on parameter-dependent quadratic Lyapunov functions, take advantage of known a priori bounds on the parameters' rates of variation (the bounds may themselves be parameter-varying). The controller achieves an induced-L 2 -norm performance objective; Level 1 flying qualities are predicted. Suboptimal solutions are obtained by solving a convex optimization problem described by linear matrix inequalities (LMIs). Incorporation of D-K iteration with "constant D-scales" provides robustness to time-varying uncertainty. Parameter-varying performance weights are used to shape the desired performance at different points in the design envelope. 1 Introduction The area of analysis and control of linear parametervarying (LPV) systems has r..