Edge Aware Anisotropic Diffusion for 3D Scalar Data

Fig. 1: The left half of the figure demonstrates the consistency in smoothing of our method compared to the existing method. The right half of the figure demonstrates the de-noising capabilities of our method. All the images from (a-c) were obtained byrenderingan iso-surface of 153. (a) Diffused with an existing diffusion model proposed by Krissian et al. [20] with k = 40, and100 iterations (b) The original Sheep’s heart data. (c) Diffused with our method with σ = 1 and the same number of iterations. The yellow circle indicates aregionwheretheiso-surfacehasbothhighandmediumrangegradient magnitude, and the blue circle marks a region where the gradient magnitude is much lower. Note the inconsistent smoothing in (a) inside the yellow circle. (d) The tooth data contaminated with Poisson noise (SNR=12.8) (e)Theoriginaltoothdata(f)Diffusedwithourmethod(SNR=25.76) withσ = 1 and 25 iterations. We used the exact same transfer function to render all the images in(d-f). Abstract—Inthispaperwepresentanovelanisotropicdiffusionmodel targeted for 3D scalar field data. Our model preserves material boundaries as well as fine tubular structures while noise is smoothed out. One of the major novelties is the use of the directional second derivative to define material boundaries instead of the gradient magnitude for thresholding. This results in a diffusion model that has much lower sensitivity to the diffusion parameter and smoothes material boundaries consistently compared to gradient magnitude based techniques. We empirically analyze the stability and convergence of the proposed diffusion and demonstrate its de-noising capabilities for both analytic and real data. We also discuss applications in the context of volume rendering

Biogas in Organic Agriculture: Utopia, Dead-End or Role model? - A Synopsis

Present-day organic biogas production provokes controversy of its role between the poles of societal demands, principles of organic agriculture and economic constraints. By integrating multiple arguments on organic biogas in a meta-level, several future trends are identified. However, only one option seems reasonable, where anaerobic digestion on a confined scale, mainly based on residual substrate input, serves both energy and food security demands while enhancing the productivity of organic farming systems

Einsatz konventionell erzeugter Kosubstrate zur Biogasgewinnung im Öko-Landbau

This article determines type and amount of non-organic substrates used for biogas production on organic farms in Germany. Furthermore, it discusses determinants and problems of non-organic substrate use. Conventional substrate – mainly maize – is extensively used in larger biogas plants on farms without sufficient land area and/or low stocking rates per kWel. These overcapacities of organic biogas plants may represent maladjustment to external preconditions as a result of bad planning as well as carefully considered exploitations of business opportunities on the basis of external inputs. In order to reduce non-organic substrate use due to bad planning, on one hand biogas consulting services which account for the particular conditions of organic agriculture should be enhanced, on the other hand farmers need to seek independent advice before concluding an agreement with an engineering company

Das Öko-Kontrollverfahren in Deutschland aus Sicht von Experten

Qualitative interviews with 13 representatives from the organic sector in Germany agencies, and academia) were conducted to investigate the perceptions and opinions regarding the organic certification process. The focus of our analysis was on (i) the reliability of the system, (ii) the cooperation of the various actors, and (iii) the competency/capacity of control personnel

The Role of Amenities in the Location Decision of Households and Firms

Traditionally, cities have been regarded as centres of production: Firms produce goods in cities because agglomeration economies make them more productive. People live in cities because firms provide jobs and income. The existence of cities and closely related location decisions by households and firms have often been explained by these production linkages. Density is thought to offer agglomeration benefits on the production side but negative congestion effects on the consumption side. More recently, urban scholars have departed from this view and considered cities not only as centres of production but also of consumption (Glaeser et al., 2001). Workers have arguably become more heterogeneous in terms of taste, more educated and their incomes have risen. Firms have become more footloose and goods more diverse (Brueckner et al., 1999; Kolko, 1999; Kotkin, 2000; Glaeser et al., 2001; Florida, 2002; Dalmazzo & de Blasio, 2011; Glaeser, 2011; Bauernschuster et al., 2012; Suedekum et al., 2012; Ahlfeldt, 2013). These developments have left workers with more leisure time and income to spend on the consumption side so that workers and firms are no longer expected to only respond to classic production links but to a wide range of amenities. This dissertation intends to shed further light on the consumer city idea. Motivated by a lack of empirical evidence, I contribute to this young field of research by investigating different aspects of the role of amenities in the location decision of households and firms. The work is structured around the classification of urban amenities as suggested by Glaeser et al. (2001). This classification as well as related literature is presented in Chapter 2. The comprehensive literature review is intended to provide a background for the analyses carried out in this work. Moreover, it shows the field’s methodological development which is characterised by a move from correlations to establishing causality. Chapter 3 investigates the role of cultural amenities in the location decision of firms. I define cultural amenities as localised goods and services, which is one of the four urban amenity categories defined by Glaeser et al. (2001). The idea is that innovative service firms are highly footloose and mainly rely on qualified labour as input factor. At the same time, highly qualified and “creative” individuals have a strong preference for a rich social and cultural life (Florida, 2002). It is therefore expected that firms, following its workers, act as amenity-maximising agents. I empirically test this hypothesis by estimating a location choice model for internet start-ups in Berlin. The identification of the cultural amenity effect is based on the fall of the Berlin Wall which is interpreted as a quasi-natural experiment. Amenities are found to positively impact on the location of web firms. A comparison with other service industries moreover suggests that amenities are significant to the location choice of creative sectors, whereas no effect can be observed for non-creative firms. Chapter 4 is centred around the amenity role of aesthetics and physical setting, and on heritage preservation in particular. Heritage designation is considered to solve an externality problem thus providing benefits to home owners, in terms of a reduction of uncertainty regarding the future of an area, but at the costs of development restrictions. The chapter proposes a simple theory of the designation process, in which it is postulated that the optimal level of designation is chosen so as to Pareto-maximise the welfare of local owners. The implication of the model is that a) an increase in preferences for historic character should increase the likelihood of a designation, and b) new designations at the margin should not be associated with significant house price capitalisation effects. The empirical results are in line with these expectations. In Chapter 5 a third type of urban amenities according to the Glaeser et al. (2001) definition is investigated in further detail, i.e. speed of transportation. Transport’s important role in economics is beyond controversy. The estimation of the impact of a new infrastructure project is, however, not entirely straightforward as the relation between transport and economic development is plagued by a notorious simultaneity problem. The allocation of transport is not completely random and may respond to demand as infrastructure projects usually require large investment costs. Conventional causal inference has approached this problem by only focusing on the uni-directional effect of transport provision. I therefore propose a method, which is well established in macroeconomics, to explore the structure of mutually related endogenous variables. In particular, I run bivariate Panel VAR models using unique historical data for Berlin during a dynamic period when most of today’s public rail network was established (1881-1935). Results do indeed suggest a simultaneously determined relation between transport and urban development. Chapter 6 extends the previous analysis of the Berlin rail sector by applying the Panel VAR methodology to the city of Chicago, Illinois, and the development of the ‘L’ train over a period of over 100 years (1910-2010). The analysis can be interpreted as both an additional robustness test and a comparative study. Results are in line with the findings for Berlin. The dissertation ends with the conclusion in Chapter 7, where I summarise the main findings and stress important contributions to the literature

STRUCTURE AND DEVELOPMENT OF SCIENTIFIC JOURNAL PUBLICATIONS ON ORGANIC AGRICULTURE: A SCIENTOMETRIC REVIEW

Basic scientometric indicators are used to analyze the corpus of 2,801 peer-reviewed scientific journal articles on organic agriculture obtained from the so-called ‘Web of Science’ databases and to compare their dynamic with the general agricultural literature (136,712 articles). Apart from the development and publication growth we review bibliometric data on author, institution, country and language in order to produce insights on the structure of international publishing on organic farming

Toward high-quality gradient estimation on regular lattices

Abstract—In this paper, we present two methods for accurate gradient estimation from scalar field data sampled on regular lattices. The first method is based on the multidimensional Taylor series expansion of the convolution sum and allows us to specify design criteria such as compactness and approximation power. The second method is based on a Hilbert space framework and provides a minimum error solution in the form of an orthogonal projection operating between two approximation spaces. Both methods lead to discrete filters, which can be combined with continuous reconstruction kernels to yield highly accurate estimators as compared to the current state of the art. We demonstrate the advantages of our methods in the context of volume rendering of data sampled on Cartesian and Body-Centered Cubic lattices. Our results show significant qualitative and quantitative improvements for both synthetic and real data, while incurring a moderate preprocessing and storage overhead. Index Terms—Approximation theory, Taylor series expansion, normal reconstruction, orthogonal projection, body-centered cubic lattice, box splines. Ç

Praxisforschungsnetzwerke - Eine explorative Studie mit Akteuren der ökologischen Landwirtschaft in Hessen

In der Praxisforschung werden LandwirtInnen als aktiv Handelnde in den Forschungsprozess eingebunden. LandwirtInnen, BeraterInnen und ForscherInnen gestalten Fragen und Inhalte gemeinsam. Dadurch entstehen Synergieeffekte, die Innovationen für eine nachhaltige Landwirtschaft hervorbringen. Durch langjährige Zusammenarbeit in Netzwerken kann erfolgsentscheidenes Vertrauen zwischen den Akteuren aufgebaut werden. In der vorliegenden Untersuchung wurden im April 2018 acht Akteure aus Hessen (LandwirtInnen, BeraterInnen und ForscherInnen) zur Praxisforschung in Hessen befragt. Hierzu wurde die Methode der Fokusgruppendiskussion genutzt. Die befragten Akteure nehmen eine Expertenstellung innerhalb ihrer Akteursgruppe ein. Die Analyse der Fokusgruppendiskussion zeigt, dass zur Zeit nur wenig Praxisforschung in Hessen betrieben wird und die Akteursgruppen schlecht untereinander vernetzt sind. Die Rahmenbedingungen für intensivere Zusammenarbeit sind sehr gut: Finanzmittel stehen zur Verfügung (Ökoaktionsplan), es gibt motivierte Akteure, es sind viele Universitäten ansässig und erfolgreiche EIP-Projekte bieten eine gute Ausgangsbasis. Um Praxisforschung im ökologischen Landbau in Hessen zu etablieren, werden AnsprechpartnerInnen und eine entsprechende Institutionalisierung benötigt. Die VÖL (Vereinigung Ökologischer Landbau in Hessen e.V.) bietet interessante Voraussetzungen für die Koordination eines Praxisforschungsnetzwerks. Die zur Zeit limitierte Versuchstechnik, eingeschränkte zeitliche Kapazitäten und räumliche Distanzen müssen dabei ebenso realistisch berücksichtigt werden wie eine faire Kostenverteilung