Extraction of Hierarchical Surface Networks from Bilinear Surface Patches

Surface networks capture the topological relations between passes of a continuous surface, the paths of steepest descent and ascent starting at the passes, and the pits and peaks where the steepest paths end. Surface networks represent the topology of surfaces in a compressed form and allow fast investigation of the surfaces' convex and concave shapes. They are applied, for instance, for enhancing algorithms for surface analysis, for surface model simplification, and for surfaces visualization. Furthermore, they are themselves subjects of analysis as they are closely coupled to the intrinsic geometrical concepts and rules of continuous surfaces.
This article extends the topology of surface networks in four ways: (i) objects at the edge of the surface model are introduced; (ii) intersections between valley and ridge lines are found to be possible, and such intersections are incorporated into the topology; (iii) horizontal areas may represent passes, pits, or peaks, and therefore must be detected and explicitly incorporated; and (iv) valley and ridge line hierarchies are recognized as inherent components of the surface network. They are extracted and explicitly represented.
To ensure consistency and completeness of the surface network, a zero-order continuous surface is specified from the raster data prior to the extraction. This article presents a method to represent and derive valley and ridge line hierarchies. The results are illustrated with two examples. The extracted networks are found to be consistent and complete. However, the extraction method tends to produce spurious pits, peaks, and passes, which form a drawback if the surface data are affected by noise.     

How Does Economic Development in Eastern Europe Affect Austria's Regions? A Multiregional General Equilibrium Framework

The paper quantifies regional welfare effects arising from the increasing trade flows between Austria and its Eastern neighbors after the opening up of Eastern Europe. We calibrate a static multiregional Computable General Equilibrium (CGE) model with benchmark data from 1994 for Austria, subdivided into nine Federal Provinces. The regions are linked by trade flows with the four Eastern neighboring countries and with the rest of the world. We simulate the effects of the increase of trade interpenetration as observed between 1989 and 1999 in a comparative static analysis. Regional welfare effects under fixed and flexible wages are presented. We also compare national CGE results with estimates obtained in a simple partial equilibrium approach.     

Expectations of scatter in equivalent-dose distributions when using multi-grain aliquots for OSL dating

In the OSL dating of sediment, the scatter in equivalent dose (D _e) between grains is almost always larger than would be expected due to counting statistics alone. Some scatter may be caused by insufficient (partial) bleaching of some of the grains prior to deposition. In order to date partially bleached sediment, it is essential to estimate the amount of scatter caused by other processes (e.g. grain-to-grain variability in the natural dose rate). Measurements of such scatter are performed at the single-grain level; by contrast, most OSL dating is performed on multi-grain subsamples, for which grain-to-grain scatter is reduced through averaging.     

Punishment Policy in the American States from 1890 to 2008: Convergence,Divergence, Synchronous Change,and Feed‐Forward Effects

This analysis of the patterns of change in the use of incarceration by the American states from 1890 through 2008 focuses on multiple themes particularly relevant to an understanding of policy arenas in which the social constructions of target populations play an important role. Specifically, the study examines whether the states have adopted more similar incarceration levels over time (converged), whether they tend to change in the same direction at the same time (synchronous change), and whether they tend to stay in the same relative positions vis‐à‐vis one another, such that the historical policy position has long‐term implications for later policy positions (“feed‐forward” effects). The results indicate that, in spite of a century of social, political, and economic integration, the policy positions of the states have not exhibited a sustained convergence toward a common level of incarceration, but have undergone cycles, with some periods of convergence followed by periods of divergence. Change has generally been synchronous—as states tend to move in the same direction at the same time as if propelled by national forces even though incarceration levels are determined by state and local policy and the use of discretion by criminal justice officials. The results also indicate a profound “feed‐forward” effect in that the position of the states vis‐à‐vis one another historically has substantial predictive power for their position in subsequent years.     

Evidence for glass ‘recycling’ using Pb and Sr isotopic ratios and Sr-mixing lines: the case of early Byzantine Sagalassos

The secondary production (working) of glass from imperial to early Byzantine times has been proven at the ancient city of Sagalassos (SW Turkey) by the existence of glass chunks, fuel ash slag and kiln fragments related to glass processing. It had been previously suggested that local green glass might have been recycled from two other locally found glass types (blue glass vessels and chunks and HIMT glass chunks). This paper provides analytical evidence for the recycling of glass next to the use of imported raw glass. The heterogeneous lead isotopic composition of the green and HIMT vessel glass at Sagalassos, with as end members on the one hand the isotopic composition of local blue glass vessels and chunks and on the other hand that of the HIMT glass chunks, could indicate the production of ‘recycled’ glass, although heterogeneous raw materials could have been used. However, the use of Sr-mixing lines confirms local recycling. It is clear that the Sr in the green and HIMT vessels is a mixture of the Sr in the aforementioned end members. It cannot be proved whether the green ‘recycled’ glass was produced from a mixture of chunks alone, or from a mixture of cullet and chunks. Suggestions are made towards the possible origin of the raw materials for the blue and HIMT glass on the basis of Sr isotopic signatures and absolute Sr contents in the glass.