University of Mannheim

About: University of Mannheim is a education organization based out in Mannheim, Germany. It is known for research contribution in the topics: Population & European union. The organization has 4448 authors who have published 12918 publications receiving 446557 citations. The organization is also known as: Uni Mannheim & UMA.

Loan growth and riskiness of banks.

Abstract: We investigate whether loan growth affects the riskiness of individual banks in 16 major countries. Using Bankscope data from more than 16,000 individual banks during 1997-2007, we test three hypotheses on the relation between abnormal loan growth and asset risk, bank profitability, and bank solvency. We find that loan growth leads to an increase in loan loss provisions during the subsequent three years, to a decrease in relative interest income, and to lower capital ratios. Further analyses show that loan growth also has a negative impact on the risk-adjusted interest income. These results suggest that loan growth represents an important driver of the riskiness of banks.

Reliable Estimation of Dense Optical Flow Fields with Large Displacements

Abstract: In this paper we show that a classic optical flow technique by Nagel and Enkelmann (1986, IEEE Trans. Pattern Anal. Mach. Intell., Vol. 8, pp. 565–593) can be regarded as an early anisotropic diffusion method with a diffusion tensor. We introduce three improvements into the model formulation that (i) avoid inconsistencies caused by centering the brightness term and the smoothness term in different images, (ii) use a linear scale-space focusing strategy from coarse to fine scales for avoiding convergence to physically irrelevant local minima, and (iii) create an energy functional that is invariant under linear brightness changes. Applying a gradient descent method to the resulting energy functional leads to a system of diffusion–reaction equations. We prove that this system has a unique solution under realistic assumptions on the initial data, and we present an efficient linear implicit numerical scheme in detail. Our method creates flow fields with 100 % density over the entire image domain, it is robust under a large range of parameter variations, and it can recover displacement fields that are far beyond the typical one-pixel limits which are characteristic for many differential methods for determining optical flow. We show that it performs better than the optical flow methods with 100 % density that are evaluated by Barron et al. (1994, Int. J. Comput. Vision, Vol. 12, pp. 43–47). Our software is available from the Internet.

Tree species composition and diversity gradients in white‐water forests across the Amazon Basin

Abstract: Aim Attention has increasingly been focused on the floristic variation within forests of the Amazon Basin. Variations in species composition and diversity are poorly understood, especially in Amazonian floodplain forests. We investigated tree species composition, richness and a diversity in the Amazonian white-water (varzea) forest, looking particularly at: (1) the flood-level gradient, (2) the successional stage (stand age), and (3) the geographical location of the forests. Location Eastern Amazonia, central Amazonia, equatorial western Amazonia and the southern part of western Amazonia. Methods The data originate from 16 permanent varzea forest plots in the central and western Brazilian Amazon and in the northern Bolivian Amazon. In addition, revised species lists of 28 varzea forest inventories from across the Amazon Basin were used. Most important families and species were determined using importance values. Floristic similarity between plots was calculated to detect similarity variations between forest types and over geographical distances. To check for spatial diversity gradients, a diversity (Fisher) of the plots was correlated with stand age, longitudinal and latitudinal plot location, and flood- level gradient. Results More than 900 flood-tolerant tree species were recorded, which indicates that Amazonian varzea forests are the most species-rich floodplain forests worldwide. The most important plant families recorded also dominate most Neotropical upland forests, and c. 31% of the tree species listed also occur in the uplands. Species distribution and diversity varied: (1) on the flood-level gradient, with a distinct separation between low-varzea forests and high-varzea forests, (2) in relation to natural forest succession, with species-poor forests in early stages of succession and species-rich forests in later stages, and (3) as a function of geographical distance between sites, indicating an increasing a diversity from eastern to western Amazonia, and simultaneously from the southern part of western Amazonia to equatorial western Amazonia. Main conclusions The east-to-west gradient of increasing species diversity in varzea forests reflects the diversity patterns also described for Amazonian terra firme. Despite the fine-scale geomorphological heterogeneity of the floodplains, and despite high disturbance of the different forest types by sedimentation and erosion, varzea forests are dominated by a high proportion of generalistic, widely distributed tree species. In contrast to high-varzea forests, where floristic dissimilarity increases significantly with increasing distance between the sites, low-varzea forests can exhibit high floristic similarity over large geographical distances. The high varzea may be an important transitional zone for lateral immigration of terra firme species to the floodplains, thus contributing to

A Theoretical Framework for Convex Regularizers in PDE-Based Computation of Image Motion

Abstract: Many differential methods for the recovery of the optic flow field from an image sequence can be expressed in terms of a variational problem where the optic flow minimizes some energy. Typically, these energy functionals consist of two terms: a data term, which requires e.g. that a brightness constancy assumption holds, and a regularizer that encourages global or piecewise smoothness of the flow field. In this paper we present a systematic classification of rotation invariant convex regularizers by exploring their connection to diffusion filters for multichannel images. This taxonomy provides a unifying framework for data-driven and flow-driven, isotropic and anisotropic, as well as spatial and spatio-temporal regularizers. While some of these techniques are classic methods from the literature, others are derived here for the first time. We prove that all these methods are well-posed: they posses a unique solution that depends in a continuous way on the initial data. An interesting structural relation between isotropic and anisotropic flow-driven regularizers is identified, and a design criterion is proposed for constructing anisotropic flow-driven regularizers in a simple and direct way from isotropic ones. Its use is illustrated by several examples.

The Thought Worlds of Marketing and Sales: Which Differences Make a Difference?:

Abstract: The literature is divided on whether differences between the thought worlds of marketing and sales are deleterious or beneficial. This article empirically investigates various facets of thought-world differences and their effects on various outcomes. It confirms that, in general, differences hamper the cooperation between marketing and sales, which leads to a lower market performance of the business unit. However, some facets of thought-world differences enhance the market performance of the business unit through a direct effect that outweighs the negative effect mediated by the quality of cooperation between marketing and sales. Market performance is enhanced if one side plays the customers' advocate while the other plays the products' advocate. Market performance is also enhanced if one side plays the advocate of short-term considerations while the other plays the advocate of long-term considerations. In contrast, differences between marketing and sales in regard to product knowledge and interp...